Luminous Landscape Forum
Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: eronald on November 14, 2007, 04:21:27 pm
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Hi Guys,
I have lengthwise striations in my P45+ images at high ISO, attached a pushed ISO 800 which shows them clearly. Is this usual for this back, or should I send it to Phase for repair ?
Edmund
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You should not push (I reckon you mean you have underexposed and pushed up via curves or levels?) a file that has been shot at ISO800. Nasty stuff happens. Not sure whether it is usual with the P45 but I have had it on all the backs I used. Never bothered to send them back. Fact of life, I figured. Maybe I am wrong?
With the Leaf I got weird greenish funky stuff, lines & patterns when lifting an underexposed file on ISO400. With the Hasselblad it is mostly magenta funky stuff.
Not sure how you took this and how far you needed to raise the exposure slider?
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Looks pretty bad. Somethings wrong with it.
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Hi Guys,
I have lengthwise striations in my P45+ images at high ISO, attached a pushed ISO 800 which shows them clearly. Is this usual for this back, or should I send it to Phase for repair ?
Edmund
[a href=\"index.php?act=findpost&pid=152818\"][{POST_SNAPBACK}][/a]
Hi Edmund,
Is the image you posted representive of the processed image or the preview? The noise reduction and other "clean up" functions do not take place until the processing takes place.
Also... very important.... was this image viewed/processed in Capture One software or with another program?
Tim
Tim Palmer
Techncal Services
Capture Integration
tim@captureintegration.com
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Tim,
I'm posting the image processed with C1 below. Above it was Photoshop CS3. The image in each case has been resized for the web. You will note the C1 version too has striations.
I actually like the rendition of the back at this Pushed ISO a lot, and would love to be able to use it for available light and night photography as it holds the highlights nicely- the random noise in itself does NOT pose a problem to me for this type of imagery, in fact I find it quite limited, but the striations wreck the pictures.
Edmund
Hi Edmund,
Is the image you posted representive of the processed image or the preview? The noise reduction and other "clean up" functions do not take place until the processing takes place.
Also... very important.... was this image viewed/processed in Capture One software or with another program?
Tim
Tim Palmer
Techncal Services
Capture Integration
tim@captureintegration.com
[a href=\"index.php?act=findpost&pid=152850\"][{POST_SNAPBACK}][/a]
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Looks Pretty Bad...
Can you maybe answer one of the question someone ask, which was did you underexpose then push the curve up to "normal" or was metering on...?
Looks like you over developed it from an under exposed file?
Snook
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Looks Pretty Bad...
Can you maybe answer one of the question someone ask, which was did you underexpose then push the curve up to "normal" or was metering on...?
Looks like you over developed it from an under exposed file?
Snook
[a href=\"index.php?act=findpost&pid=152881\"][{POST_SNAPBACK}][/a]
The image I show is manually underexposed -to get the picture- , and then pushed by pushing the exposure slider up.
Unfortunately, now that I know what to look for I am noticing the same striations in dark areas of ISO 400 images. I have just developed the FIRST picture I took with this back, the one of the gentleman who sold it to me. It's 400 ISO, and when processed then curved slightly in PS, with the same curve I always use, and sharpened, clearly shows striations in the dark areas (see reduced crop).
I guess I have answered my own question, this back is probably broken.
Edmund
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edmund...if i understand this correctly (and after reading your email) you expect the files to be clean when shot at 800 and underexposed 2 stops (which really means you are shooting at 3200)....it's just not going ot work....my P30 behaves at 100, i can really open the shadows, use all sliders in LR and everything stays clean, but the higher up you go the uglier it gets and the less you can do to the files....i am sure the P+ files give you an extra stop, the P30+ would give you better performance then the P45+ but either way you are asking too much....
BTW someone here mentioned the canons...don't even try underexposing 2 stops with any canon even at 100....the little detail that is in the shadows with a correct exposure will be totally gone....
you can shoot the pshase backs at high asa, i love the "grain" but you have to be much more careful with your exposure....
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Paul,you hit the nail on the head!
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Actually, I wondered whether the P45+ Phase backs can be shot at 1600. You only know if you try. So I shot a set of images in available darkness to test the back and my ability to focus. And the answer seems to be yes, for lifestyle stuff 1600 is ok and probably 3200 barely IF your back is ok.
My back appears to have a defect so that even properly exposed 400 is damaged a bit. As far as file quality is concerned (without striations) 400 ISO when well exposed is good enough for anything I plan to do with the back. I now need to get that striation problem sorted out.
I do realize that my point of view is different from that of most members of this forum. However, most of the shots I've had run in magazines have run at quarter-page size, full page max, and some grain is acceptable in my catwalk shooting as it is essentially photojournalism. As for the arty stuff which I mostly do for my own amusement, grain is really not a problem.
Edmund
edmund...if i understand this correctly (and after reading your email) you expect the files to be clean when shot at 800 and underexposed 2 stops (which really means you are shooting at 3200)....it's just not going ot work....my P30 behaves at 100, i can really open the shadows, use all sliders in LR and everything stays clean, but the higher up you go the uglier it gets and the less you can do to the files....i am sure the P+ files give you an extra stop, the P30+ would give you better performance then the P45+ but either way you are asking too much....
BTW someone here mentioned the canons...don't even try underexposing 2 stops with any canon even at 100....the little detail that is in the shadows with a correct exposure will be totally gone....
you can shoot the pshase backs at high asa, i love the "grain" but you have to be much more careful with your exposure....
[a href=\"index.php?act=findpost&pid=152896\"][{POST_SNAPBACK}][/a]
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Actually, I wondered whether the P45+ Phase backs can be shot at 1600. You only know if you try. So I shot a set of images in available darkness to test the back and my ability to focus. And the answer seems to be yes, for lifestyle stuff 1600 is ok and probably 3200 barely IF your back is ok.
My back appears to have a defect so that even properly exposed 400 is damaged a bit. As far as file quality is concerned (without striations) 400 ISO when well exposed is good enough for anything I plan to do with the back. I now need to get that striation problem sorted out.
Edmund
[a href=\"index.php?act=findpost&pid=152904\"][{POST_SNAPBACK}][/a]
I think PSS was right on...
and I am sure if you go to the Moyen Format shop he'll tell you the same.
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I think PSS was right on...
and I am sure if you go to the Moyen Format shop he'll tell you the same.
[a href=\"index.php?act=findpost&pid=152905\"][{POST_SNAPBACK}][/a]
David,
My impression after spending the evening looking at these shots is that my problem appears at ISO 400, where it is NOT supposed to happen. The ISO 400 shot already has problems, and that one is well exposed. I expect usable ISO 400 from this back, grain is not a problem, lines are a problem.
Edmund
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My P25 (not +) looks much better than that at 800.
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David,
My impression after spending the evening looking at these shots is that my problem appears at ISO 400, where it is NOT supposed to happen. The ISO 400 shot already has problems, and that one is well exposed. I expect usable ISO 400 from this back, grain is not a problem, lines are a problem.
Edmund
[a href=\"index.php?act=findpost&pid=152907\"][{POST_SNAPBACK}][/a]
have you tried long expo to see what you get...
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That is the classic result of gross underexposure, coupled with boosting the exposure slider in processing the raw file.
Were you at the limits of open aperture, and long shutter? (IE: f1.8 and 1/30s)
If so, you've simply exceeded the capabilities of the sensor.
I get the same results when I push an underexposed Canon 1Ds image by 3 stops (and the majority of the image is still in the bottom 1/4 tone).
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have you tried long expo to see what you get...
[a href=\"index.php?act=findpost&pid=152911\"][{POST_SNAPBACK}][/a]
David
No, I haven't tried it. My only real "exceptional" need is for filmlike 400 ISO for fashion (and the grain on this back is ok for me if the striations weren't there). With Canon I have done exposures of 2 mins in the past for interior design catalogs, but I have no imperative need to go there again.
Edmund
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No, I haven't tried it. My only real "exceptional" need is for filmlike 400 ISO for fashion (and the grain on this back is ok for me if the striations weren't there). With Canon I have done exposures of 2 mins in the past for interior design photos, but I think I will leave that to specialists in the future.
Edmund
[a href=\"index.php?act=findpost&pid=152915\"][{POST_SNAPBACK}][/a]
may be it worth to try long expo low iso to see how it behaves.
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may be it worth to try long expo low iso to see how it behaves.
[a href=\"index.php?act=findpost&pid=152916\"][{POST_SNAPBACK}][/a]
David,
On second thoughts, I guess you're right. I'll dig out a tripod tomorrow and let down the blinds
Edmund
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These lines shouldn't be there, sure an incorrectly exposed file will have certain noise problems but lines, I dont think so. When you pay 30 grand for something you deserve to have it work correctly. And by the way, I heard from a little birdy in one of the major phase one dealers that strange lines on high iso files with the plus backs is a known issue. I'd demand a refund or a back that didnt have the problem, the non plus backs dont have this issue I heard, mine certainly doesnt, what a great upgrade eh?
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I have seen my dealer and given him example images. He is sending reports to Phase One. We will see how they answer.
Gotfred sent me some images he made with his back @ISO 800 (Thank You!), I haven't yet fully checked them out.
One unfortunate fact is that once you have noticed the lines your eyes pick them out on every image that has them. I guess if an AD gets one really bad image she might then start to get picky even about the acceptable ones.
Based on some conversations I have had with industry insiders, I am starting to wonder whether this is not a signal processing issue linked to the speed at which the CCD is clocked in the new P+ backs. I don't think it's really a sensor issue. Pure conjecture of course.
The good new in this story is that the current generation of non-microlens sensors with the current electronics in the P+ backs appear to be capable of images processed to at least 1600 ISO if you were happy with the grain of 1600 ISO film and if they fix this striation/banding issue.
Edmund
These lines shouldn't be there, sure an incorrectly exposed file will have certain noise problems but lines, I dont think so. When you pay 30 grand for something you deserve to have it work correctly. And by the way, I heard from a little birdy in one of the major phase one dealers that strange lines on high iso files with the plus backs is a known issue. I'd demand a refund or a back that didnt have the problem, the non plus backs dont have this issue I heard, mine certainly doesnt, what a great upgrade eh?
[a href=\"index.php?act=findpost&pid=153029\"][{POST_SNAPBACK}][/a]
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I am not much having much luck with the local Phase One agent Prophot, so far. They did not contact me or my dealer to say what was happening. Calling them elicited a blank, then a callback where they claimed that their sole technician did send my files on to Phase One - this tech is now on vacation.
Edmund
I have seen my dealer and given him example images. He is sending reports to Phase One. We will see how they answer.
Edmund
[a href=\"index.php?act=findpost&pid=153206\"][{POST_SNAPBACK}][/a]
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I am not much having much luck with the local Phase One agent Prophot, so far. They did not contact me or my dealer to say what was happening. Calling them elicited a blank, then a callback where they claimed that their sole technician did send my files on to Phase One - this tech is now on vacation.
Edmund
[a href=\"index.php?act=findpost&pid=154823\"][{POST_SNAPBACK}][/a]
Is after-sales-service a sore point with Phaseone for owners of P backs? I seem to get that impression when reading on Phase forum.
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I think Phase One just insists that you go through a dealer, If you have a responsive dealer you won't have any trouble. In the US anyway, you have your choice of different ones to work with.
I have been very happy with mine, and I have had to deal with some issues too.
I have tried underexposing at 800 on my 45+ and bringing the exposure compensation up. The results are not that great, lots of grain and magenta green stuff in the shadows. I don't however see the kind of striation or lines that Edmund is getting.
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I thought it common knowledge that under exposing and pushing caused this effect. Personally I Find the Dalsa chips to look even worse. I'd love to the see the unpushed histogram, and I'd bet its all lumped to the left. I'll also, bet that a PROPERLY exposed shot at this iso will look fine (if it looks like this send it back). Even properly exposed images at hi iso will have "clean" hi-light and mid-tones with slightly less pleasing shadows. Personally, I find Phase handles this situations better than most. Underexposing any digital device and pushing always looks bad no matter how much you pay.
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For further entertainment, here is another ISO 800 pushed image.
Not only does this one show more stripes the more you look, but it also falls apart nicely into a left half and a right half (look at the bottom to spot the break).
I'd be very happy with this back's Hi_ISO performance if it didn't show these artefacts.
Edmund
I thought it common knowledge that under exposing and pushing caused this effect. Personally I Find the Dalsa chips to look even worse. I'd love to the see the unpushed histogram, and I'd bet its all lumped to the left. I'll also, bet that a PROPERLY exposed shot at this iso will look fine (if it looks like this send it back). Even properly exposed images at hi iso will have "clean" hi-light and mid-tones with slightly less pleasing shadows. Personally, I find Phase handles this situations better than most. Underexposing any digital device and pushing always looks bad no matter how much you pay.
[a href=\"index.php?act=findpost&pid=154854\"][{POST_SNAPBACK}][/a]
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what a great upgrade eh?
[a href=\"index.php?act=findpost&pid=153029\"][{POST_SNAPBACK}][/a]
I never did upgrade my P45....... never saw the value. I agree with your analysis, but I still am a loyal customer of phase.
Victor
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Edmund, you could have contacted phase directly with your files and then gone to your dealer if they told you you needed to send the back in. They were pretty quick to get back to me, with my experience dealing with my dealer (calumet) i definitely got things done quicker this way.
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For further entertainment, here is another ISO 800 pushed image.
Not only does this one show more stripes the more you look, but it also falls apart nicely into a left half and a right half (look at the bottom to spot the break).
I'd be very happy with this back's Hi_ISO performance if it didn't show these artefacts.
Edmund
[a href=\"index.php?act=findpost&pid=154859\"][{POST_SNAPBACK}][/a]
Even without the striations (is that the right word? ) I cannot see the usefullness of this image as there is zero zilch zip shadow detail???
Jo S. x
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For further entertainment, here is another ISO 800 pushed image.
Not only does this one show more stripes the more you look, but it also falls apart nicely into a left half and a right half (look at the bottom to spot the break).
I'd be very happy with this back's Hi_ISO performance if it didn't show these artefacts.
Edmund
[a href=\"index.php?act=findpost&pid=154859\"][{POST_SNAPBACK}][/a]
Pushing the shadows so much won't give you any satisfactory result, specially if the shadows are just pure black. Could you post a sample of the original exposure? The image is sharp so I suppose you're getting really dark images aren't you? How about a flash?
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Based on some conversations I have had with industry insiders, I am starting to wonder whether this is not a signal processing issue linked to the speed at which the CCD is clocked in the new P+ backs. I don't think it's really a sensor issue. Pure conjecture of course.[a href=\"index.php?act=findpost&pid=153206\"][{POST_SNAPBACK}][/a]
It depends on how you define "sensor". It is definitely not an issue with the photosites themselves; they seem quite capable of providing a usable image here. These are offsets in the blackpoint of entire lines from the two sensors. That means that is has something to do with the reading and digitization of entire lines from each of the two sensors in the camera, and is therefore an issue in the readout electronics at the edge of the sensor or somewhere down the chain in the camera. It is especially noticeable with Tungsten white balance, because the blue channel is usually multiplied by 3x to 5x for very warm light sources, while green is anchored and red is already very close to being balanced in the RAW state for warm lighting. Where you see blue bands, the blackpoint that the camera has for that line is too low, IOW true black might not be 0, but what registers as 0.8 or 1.7 for that line (and the discrepancy is further magnified by the white balance process).
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Even without the striations (is that the right word? ) I cannot see the usefullness of this image as there is zero zilch zip shadow detail???
[a href=\"index.php?act=findpost&pid=155250\"][{POST_SNAPBACK}][/a]
Maybe you'd see subtle detail if there weren't striations?
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I can't understand what all the fuss is about. Edmund has posted an ISO 800 image on another current thread, 'High ISO versus Underexposure' at http://luminous-landscape.com/forum/index....pic=20997&st=40 (http://luminous-landscape.com/forum/index.php?showtopic=20997&st=40) where it is demonstrated that the image showing banding and striations in the shadows, as well as a lot of noise, is in fact drastically underexposed.
The only uncertainty in my mind is the degree to which the image is underexposed. My estimate from ACR is 1.7 stops. Others seem to think it's as much as 4 stops. Whether it's 4 stops underexposed or only 1.7 stops underexposed, I would say an additional 1.7 stops of exposure would have been sufficient to remove that banding and a lot of the noise.
If you want a film-like texture, wouldn't it be better to expose correctly in the first place and then add grain later in Photoshop.
Banding, striations and heavy noise are always a consequence of underexposure when the scene has a fairly high dynamic range, whatever the ISO, in my experience at least.
If I take a shot of a sunset with my Canon 5D at ISO 100 and neglect to give a full exposure to the right, I'll likely get very ugly banding in the deepest shadows.
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Here's a link to a Raw file EXPOSED TO THE RIGHT at 400 ISO, in DAYLIGHT.
http://download.yousendit.com/D9E8BE575BC4D993 (http://download.yousendit.com/D9E8BE575BC4D993)
Push it through C1 3.77 with no adjustments and you will be able to see a light line just under the stem of the pear, leading to the right. The streaking I complain about is present but less noticeable with normal exposure, but a fashion person, or color consultant will see it immediately.
Edmund
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I just downloaded the file but by no means it has been exposed to the right. In ACR it can be pushed up anywhere between 1 and 2 stops before it gets acceptable. It would have needed almost 2 stops more to be exposed to the right.
Indeed I see magenta and green Gremlins especially in the dark parts but nothing that is really upsetting considering on how much I had to adjust exposure.
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Edmund,
What on earth are you doing? Another image that's underexposed even by my very conservative standards. Here's the ACR window showing a +1.75 stop correction.
[attachment=4007:attachment]
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Edmund,
What on earth are you doing? Another image that's underexposed even by my very conservative standards. Here's the ACR window showing a +1.75 stop correction.
[attachment=4007:attachment]
[a href=\"index.php?act=findpost&pid=155473\"][{POST_SNAPBACK}][/a]
I just downloaded the file but by no means it has been exposed to the right. In ACR it can be pushed up anywhere between 1 and 2 stops before it gets acceptable. It would have needed almost 2 stops more to be exposed to the right.
Indeed I see magenta and green Gremlins especially in the dark parts but nothing that is really upsetting considering on how much I had to adjust exposure.
[a href=\"index.php?act=findpost&pid=155450\"][{POST_SNAPBACK}][/a]
Exposing to the right in ACR and C1 are two different things. ACR will consistently show 1-2 stops less exposure in my experience. If you run the files through C1 the histogram will be very different.
If you change the default curve in C1 from film standard to Linear response, the result is akin to ACR but will not look good... I'm a newbie to C1, so I don't know how other users deal with this.
The image is exposed too low anyway, as ACR is correct and C1 is not... so you are both right.
-axel
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Exposing to the right in ACR and C1 are two different things. ACR will consistently show 1-2 stops less exposure in my experience. If you run the files through C1 the histogram will be very different.
If you change the default curve in C1 from film standard to Linear response, the result is akin to ACR but will not look good... I'm a newbie to C1, so I don't know how other users deal with this.
The image is exposed too low anyway, as ACR is correct and C1 is not... so you are both right.
-axel
[a href=\"index.php?act=findpost&pid=155498\"][{POST_SNAPBACK}][/a]
So, is this contretemp really all about differences in the way C1 and ACR handle images? A one and 2/3rds stop difference to me is so significant I find it difficult to believe that any major program like C1 could operate like that.
Does the ACR image not look good? There are hundreds of adjustments in ACR you can make if you think the image is not quite right.
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When evaluating exposure, one should always have the RAW converter's TRC set to linear. Otherwise it's too easy to misjudge whether or not you've exposed correctly when looking at the image in the RAW converter. Once exposure is set correctly, then tweak the TRC as needed/desired. This is probably the root of the controversy over whether expose to the right works with MFDBs.
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These lines shouldn't be there, sure an incorrectly exposed file will have certain noise problems but lines, I dont think so. When you pay 30 grand for something you deserve to have it work correctly. And by the way, I heard from a little birdy in one of the major phase one dealers that strange lines on high iso files with the plus backs is a known issue. I'd demand a refund or a back that didnt have the problem, the non plus backs dont have this issue I heard, mine certainly doesnt, what a great upgrade eh?
[a href=\"index.php?act=findpost&pid=153029\"][{POST_SNAPBACK}][/a]
I have never owned phase but would guess that this is just horrible underxposure
whithout seeing the under unprocessed levels it is really impossible to judge
it is fundamentally a 100ISO or 50ISO chip and the fact that is works at 400 or well exposed 800 makes it a fantastic tool and a leap from the generatation of backs that crap out at about 100
It will never be a D3 or whatever
Choose the right tool for the job ??
S
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When evaluating exposure, one should always have the RAW converter's TRC set to linear. Otherwise it's too easy to misjudge whether or not you've exposed correctly when looking at the image in the RAW converter. Once exposure is set correctly, then tweak the TRC as needed/desired. This is probably the root of the controversy over whether expose to the right works with MFDBs.
[a href=\"index.php?act=findpost&pid=155514\"][{POST_SNAPBACK}][/a]
TRC? Are you referring to this?
[attachment=4013:attachment]
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Flexcolor also does tend to underexpose slightly compared with ACR, so does Leaf Capture but there we are talking in the range of about half a stop not 2. I always take this into consideration and overexpose slightly while working with Flexcolor (as I did with LC as well).
With Flexcolor I once made the mistake of not setting my exposure back to normal (0), I also once made the mistake of not setting my levels back to default. This resulted in images way off. Could something like this have happened to C1?
I have tried a demo version of C1 about a year ago. I did not like it and have not looked at it again so I cannot say anything about it.
Looking at this I am convinced this image would have looked excellent if it had about 2 more stops.
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No Problem with your Back - just don't underexpose at a high iso - I shoot MOST
of the time with my 30+ at iso800, very clean files, as long as I do not underexpose.
David,
On second thoughts, I guess you're right. I'll dig out a tripod tomorrow and let down the blinds
Edmund
[a href=\"index.php?act=findpost&pid=152918\"][{POST_SNAPBACK}][/a]
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I find it quite extraordinary that such professional photographers who spend so much on their equipment should be so ignorant of these basic principles of ETTR.
My mind boggles. Should they all be sacked and sent off to Siberia?
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No, but it does demonstrate that just because you photograph models that have a $10000 day rate doesn't automatically mean you have a good grasp of the technical side of things. I find this rather amusing after all of the pomposity posted in the MFDB/ETTR thread. This is an excellent example of why ETTR is a good idea, even for MFDB shooters.
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I somehow knew you would bring that up again.
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You still have +1.85 step for this image to be exposed "to the right". Still, the blue channel is clipped in the shadow areas. This is because I'm recovering the exposure and this details has been lost. If you continue to underexpose your captures you'll always find this problem and a lot of noise.
(http://www.samuelaxelsson.com/temp/p45.jpg)
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Samuel, I can see the stripes on your screenshot - has anyone else seen this type of fault ?
I think the fruit file ends up with around 230,230, 230 RGB values on the business card, if it is pushed through C1 with the standard film curve (not linear). This is certainly not severe underexposure.
I would be sure, but C1 just crashed on me yet again. It really doesn't like files from my back somehow. I have tried downloading C1 again, but that hasn't helped, it just crashed again. I can post my saved copy of the rendered Tiff if that helps.
I really wonder whether my files aren't corrupted somehow. I have tried using a different memory card but that didn't change much.
Edmund
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Edmund,
Try exposing for ACR and see how that ends up. In the fruit file the Orange clips first with ACR (the spectacles on the orange that is ofcourse) ! While the business card is still below 255,255,255.
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TRC? Are you referring to this?
Yes. You want the TRC set to linear while adjusting the Exposure slider because if you have a curve set to give a smoother rolloff to the highlights and shadows, a large exposure adjustment may make only small adjustments to the white and black points, which makes it much more difficult to tell if you got exposure correct in-camera or not. OTOH, with a linear TRC the movement of the white and black points correlates much more closely with movement of the exposure slider and the amount of exposure in the camera, and it's a lot easier to tell from the RAW converter histogram whether the shot should have had more or less exposure. Once exposure is set optimally, then one can tweak the TRC as needed to get whatever look is desired from the image.
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No, but it does demonstrate that just because you photograph models that have a $10000 day rate doesn't automatically mean you have a good grasp of the technical side of things. I find this rather amusing after all of the pomposity posted in the MFDB/ETTR thread. This is an excellent example of why ETTR is a good idea, even for MFDB shooters.
[a href=\"index.php?act=findpost&pid=155535\"][{POST_SNAPBACK}][/a]
Not going again into this topic, but this is just false again. In medium format digital you need to "expose right". Two stops under clipping is an underexposed image. It has nothing to do with ETTR. The histogram of a correct exposure in MFD looks centered.
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This image, CF000965, is less underexposed:
(http://www.panopeeper.com/Demo/Edmund_CF000965_raw_histogram.gif)
compared to the former one, CF000598:
(http://www.panopeeper.com/Demo/Edmund_CF000598_raw_histogram.gif)
However, it still tops out at level 7500. In fact, only 0.0168% of the green pixels are over 7300.
If the DNG converter's information is true, namely that the numerical range is de facto 0-65535, then it is still 2.95 stops away from the right end.
However, the dark end is not as bad as the other image is: "only" 10.5% of the pixels are zero (i.e. totally lost), but 47% of the pixels are under level 50. This makes the greyish cloth of this jacket or whatever not only noisy but off-color.
Anyway, is the streak you are referring to the one between the arrows here?
Crop of streaky area (http://www.panopeeper.com/Demo/Edmund_CF000965_streak.jpg)
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Panopeeper, are you sure your software is processing the files in a way similar to the standard Raw converters ????
In the C1 histogram one can clearly distinguish the black cloth, at the left, and the fruit at the center, and the business card more to the right.
(http://edmundronald.googlepages.com/Picture14.jpg)
Edmund
This image, CF000965, is less underexposed:
(http://www.panopeeper.com/Demo/Edmund_CF000965_raw_histogram.gif)
[a href=\"index.php?act=findpost&pid=155547\"][{POST_SNAPBACK}][/a]
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Panopeeper, are you sure your software is processing the files in a way similar to the standard Raw converters ????
I am sure it does not. It is not a raw processor but a raw analyzer. The histogram I posted reflects the unadultered raw data, that what your camera created, not how it is interpreted. The histogram after setting the white point for the card, white balancing on the card and mapping to sRGB without any other adjustment would look so:
(http://www.panopeeper.com/Demo/Edmund_CF000965_mapped_histogram.gif)
The histogram you see with C1 shows the outcome of the conversion.
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Panopeeper
It would seem that using linear scales will push all low-key imagery well into the left 10% of any linear graph. After all, every low-key image has most data 4 stops below the max.
Maybe some base-2 log scales (f-stops) - on the x axis- would be more appropriate to photographic usage, albeit less spectacular ?
Edmund
I am sure it does not. It is not a raw processor but a raw analyzer. The histogram I posted reflects the unadultered raw data, that what your camera created, not how it is interpreted. The histogram after setting the white point for the card, white balancing on the card and mapping to sRGB without any other adjustment would look so:
(http://www.panopeeper.com/Demo/Edmund_CF000965_mapped_histogram.gif)
The histogram you see with C1 shows the outcome of the conversion.
[a href=\"index.php?act=findpost&pid=155559\"][{POST_SNAPBACK}][/a]
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Ronald,
Go back and open up 1 1/2 stops at ISO 800 and then post that raw file.
I'm really stunned that you don't understand that when you underexpose an image nearly two stops with any digital camera that you're going to get all sorts of funkiness.
Furthermore, the concept of pushing and pulling development might work with film but I've never seen it work the way you're wanting it to with digital.
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Show us a straight curve on the pic of the woman..
Theses images are way under by the look of it
I am a flash and reflector nut because IMO most scenes need the DR compessing to get a good file ie to lift the shadows that you want to keep
With the card and fruit pic the card needed to be scraping the top of the curve or even 'recovered' by doing HDR
Do some test on recovering highlights - exellent in sinar - dont know about phase
Low key look is created by making a deep S in the Raw Curve not be exposing like that
I assume you expose by chimping the histo not checking the camera meter
and base you noise expectations that the 100ISO base of the P45 is being pumped up with EIGHT times less light than the sweet spot
I have friend who is very happy that his 45 is good at 200
My calculations on getting clean 800 revolve around the D3 which is being trumpeted as 25000000 ISO
S
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So, is this contretemp really all about differences in the way C1 and ACR handle images? A one and 2/3rds stop difference to me is so significant I find it difficult to believe that any major program like C1 could operate like that.
Does the ACR image not look good? There are hundreds of adjustments in ACR you can make if you think the image is not quite right.
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I started out not believing what my eyes told me in C1, but compared to ACR and Flex, it pushes midtones and highlights upwards between 1 and 2 stops. I frequently push midtones in Flex about 1,05 to 1,15 on the levels adjuster to get a pleasant "modern" result, but don't blow any highlights etc. The same is not true for C1 where i have to "pull back" instead. I have used the H3D-39 since its release date, as well as the H2+CFH-39 before that. I am now in my 3rd week using C1 and my P45+ (not a long time, I know). Yet as far as defaults go, C1 pushes midtones and highlights a lot, and I'm beginning to wonder if this is not the reason why so many users find the C1 conversions pleasing. Its a "fully pushed and pulled" file straight away, contrary to Flex where you start more closely to zero, and work your way up.
-axel
EDIT: See the attatched files for examples of what I mean using Edmunds file as a basis. I can see how someone could be fooled by the histogram in C1 if using it as a basis for determining exposure, as I was initially. The furthermost left part with information in it, is just a stop or two shy of white clipping, but in reality is quite a lot more underexposed.
[attachment=4025:attachment]
[attachment=4026:attachment]
[attachment=4028:attachment]
[attachment=4027:attachment]
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Axel,
Seeing you have a P45+, could you post some underexposed shots at hi iso please ?
Edmund
I started out not believing what my eyes told me in C1, but compared to ACR and Flex, it pushes midtones and highlights upwards between 1 and 2 stops. I frequently push midtones in Flex about 1,05 to 1,15 on the levels adjuster to get a pleasant "modern" result, but don't blow any highlights etc. The same is not true for C1 where i have to "pull back" instead. I have used the H3D-39 since its release date, as well as the H2+CFH-39 before that. I am now in my 3rd week using C1 and my P45+ (not a long time, I know). Yet as far as defaults go, C1 pushes midtones and highlights a lot, and I'm beginning to wonder if this is not the reason why so many users find the C1 conversions pleasing. Its a "fully pushed and pulled" file straight away, contrary to Flex where you start more closely to zero, and work your way up.
-axel
[a href=\"index.php?act=findpost&pid=155638\"][{POST_SNAPBACK}][/a]
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Even in C1 you are clipping the blacks.
Probably get away with it on 50 ISO but on 800... No chance!
Reshoot!
Jo S.x
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Even in C1 you are clipping the blacks.
Probably get away with it on 50 ISO but on 800... No chance!
Reshoot!
[a href=\"index.php?act=findpost&pid=155735\"][{POST_SNAPBACK}][/a]
There is no such thing as "clipping the blacks", as far as user expsoure is concerned. A RAW histogram is not a symmetrical entity; the left side is anchored, and the right side is scalable.
However, bad cameras and converters can clip black, but that is independent of exposure.
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There is no such thing as "clipping the blacks", as far as user expsoure is concerned. A RAW histogram is not a symmetrical entity; the left side is anchored, and the right side is scalable.
However, bad cameras and converters can clip black, but that is independent of exposure.
[a href=\"index.php?act=findpost&pid=155747\"][{POST_SNAPBACK}][/a]
I'm going to bake up some tools myself, and take the Raw file apart - these black values shown by Panopeeper's tool sound preposterous, except if there is some very strong massaging of the data before the Raw file gets written. I'm also going to shoot @ISO 200 and push, just to see what happens.
Edmund
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these black values shown by Panopeeper's tool sound preposterous, except if there is some very strong massaging of the data before the Raw file gets written.
1. the black values are unquestionable,
2. the relative values are questionable. I suggested you to shoot a white board with at least four stops overexposure and post the resulting raw; then I can determine the true clipping points (do this with several ISO, because it *may* depend on the ISO, I don't know your camera).
If it turns out, that the clipping points are at 16000, then the underexposure is only one stop away from the right edge. If the clipping points are somewhere else, the "distance to the right" changes.
Adobe DNG converter gets it wrongly with my Canon 40D as well: it always shows 13600, while the actual clipping is between 12700 and 16383, depending on the ISO.
(I mentioned clipping points in plural, because the different "colored" pixels may have different clipping points, though the difference won't be much.)
3. Why don't you shoot a "normal" daylight scenery with ISO 100 as high as you think you can go (and another one with +1 EV) and post those, for verification
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Panopeeper,
1. First of all, we have no idea what actually comes off the sensor of a Phase One camera. At least I don't at this point, if we had signed an NDA we wouldn't be talking. All we are seeing is what gets written to file.
2. Then we don't *really* know what is in this file, because, again, we only know what Dcraw is squeezing out of it, and Dave doesn't necessarily have a *complete* map to all the tricks of the format.
3. I do think you should change the x scales so one look would be enough to compare data with the histograms we see in the Raw converters, and this would tell us what the black box Raw converters like C1 are doing to the data.
4. I would really like to see what is going on with the *dark* pixels. Tracing these, maybe via a color map around a thumbnail would be *VERY VERY INTERESTING*
Edmund
1. the black values are unquestionable,
2. the relative values are questionable. I suggested you to shoot a white board with at least four stops overexposure and post the resulting raw; then I can determine the true clipping points (do this with several ISO, because it *may* depend on the ISO, I don't know your camera).
If it turns out, that the clipping points are at 16000, then the underexposure is only one stop away from the right edge. If the clipping points are somewhere else, the "distance to the right" changes.
Adobe DNG converter gets it wrongly with my Canon 40D as well: it always shows 13600, while the actual clipping is between 12700 and 16383, depending on the ISO.
(I mentioned clipping points in plural, because the different "colored" pixels may have different clipping points, though the difference won't be much.)
3. Why don't you shoot a "normal" daylight scenery with ISO 100 as high as you think you can go (and another one with +1 EV) and post those, for verification
[a href=\"index.php?act=findpost&pid=155871\"][{POST_SNAPBACK}][/a]
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All we are seeing is what gets written to file
That's right, but isn't it irrrelevant, what the camera is doing with the raw data before writing the file, if we have to live with the file?
Then we don't *really* know what is in this file, because, again, we only know what Dcraw is squeezing out of it
I am not using DCraw. At this point I am working with DNG converted from your images by the Adobe DNG converter, because I don't know the characteristics of the original raw file (it is very messy).
I do think you should change the x scales so one look would be enough to compare data with the histograms we see in the Raw converters
I think you don't understand the problem. If one wants to know, how far the exposure is from the very right (i.e. from clipping), one has to know, where the clipping occurs. This can not be determined from the images you presented, because there is none clipping there.
The fact, that the camera delivers 16bit data does not mean, that the actual values go up to 64K.
Anyway, do it as you see it fit, it's your problem.
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I find it quite extraordinary that such professional photographers who spend so much on their equipment should be so ignorant of these basic principles of ETTR.
My mind boggles. Should they all be sacked and sent off to Siberia?
[a href=\"index.php?act=findpost&pid=155534\"][{POST_SNAPBACK}][/a]
Well, how is he supposed to know where the right is? How do you know where it is?
What kind of feedback is his camera giving?
Where is the clipping point in the P45+ RAW data?
Are the higher ISOs actually unique digitizations or just logistics?
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Well, how is he supposed to know where the right is? How do you know where it is?
What kind of feedback is his camera giving?
Where is the clipping point in the P45+ RAW data?
Are the higher ISOs actually unique digitizations or just logistics?
[a href=\"index.php?act=findpost&pid=155964\"][{POST_SNAPBACK}][/a]
Perhaps I'm making incorrect assumptions based upon the way 35mm DSLRs operate. I rely upon the flashing highlight warning and the appearance of the histogram to tell me how close I am to full exposure. But first I have the camera's jpeg picture options set to minimum contrast such that a very small area of 'apparent' highlight clipping indicates exposure is a correct ETTR. Without that minimum contrast setting, I'd be underexposing all the time when shooting RAW, which is fine for out-of-the-box jpeg images of course which have to be underexposed to avoid highlight clipping.
There seems to be an unavoidable but small degree of guesswork here. Even with contrast at a minimum, a histogram and review image with no highlight flashing at all is still likely to be underexposed by a small amount, perhaps 1/2 a stop.
One more accurate approach, which unfortunately is a bit slow and cumbersome which is why I don't use it, is to take a spot meter reading of the brightest part of the scene and then increase exposure by 4 stops. But it's so long since I used this approach I can't be sure if it's 4 stops or less. Whatever it was, it worked just fine.
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Perhaps I'm making incorrect assumptions based upon the way 35mm DSLRs operate
You certainly are, if you believe, that it has to do with 35mm DSLR.
The issue is, that the histogram the camera displays is based on the resulting JPEG image (in case of raw recording, there is a JPEG image embedded in the raw file).
That JPEG has been created from the raw data based on the camera settings:
- contrast
- saturation
- sharpening
- color tone
but the single biggest factor is the white balance (which is not always a setting, it may have been evaluated by the camera).
I posted some raw histograms on this thread, and later the corresponding RGB histogram without de-mosaicing but after white balancing. You may notice, that the raw green values are over twice as high as the reds, but in the resulting image they end up as high as the green (the brightest part of that image is the white card, i.e. red, green and blue has to be equal at the right end).
There are some enviable cameras (or cameras of some enviable owners), which accept coefficients as setting. Some Nikons do that; in Canons only the very top models are on par.
Otherwise you have to experiment a lot with your camera to find out a WB setting (not only temperature but tint as well), which results in coefficients 1.0, 1.0, 1.0.
I rely upon the flashing highlight warning and the appearance of the histogram to tell me how close I am to full exposure
It is unreliable without the right guessing of WB.
There are some downsides of such a "raw setting":
- the image appears off-color on the camera,
- the thumbnail is off-color,
- the embedded JPEG is useless,
- you can not reasonably combine raw with in-camera JPEG
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You certainly are, if you believe, that it has to do with 35mm DSLR.
The issue is, that the histogram the camera displays is based on the resulting JPEG image (in case of raw recording, there is a JPEG image embedded in the raw file).
[a href=\"index.php?act=findpost&pid=155997\"][{POST_SNAPBACK}][/a]
If what has to do with 35mm DSLR?
I realise that the camera's review image is based on a converted jpeg which is why I set the camera's picture modes to minimum contrast, and minimum saturation even though I'm shooting RAW, because I find the flashing highlight warning is then more accurate, but still slightly overstated.
One has to work with the tools one has and experiment to see what approach gives the most accurate result and in what circumstances. When in doubt, autobracket exposure.
What I meant when I said I might be making some incorrect assumtions is that perhaps I've assumed that an MFDB back has a histogram and review image along similar lines to a 35mm DSLR's. If this is not the case and for some reason the exposure feed-back on an MFDB is not as sophisticated as that on a 35mm DSLR, then I take back my comment.
No need to sack these guys and send them off to Siberia .
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Otherwise you have to experiment a lot with your camera to find out a WB setting (not only temperature but tint as well), which results in coefficients 1.0, 1.0, 1.0.
It is unreliable without the right guessing of WB.
There are some downsides of such a "raw setting":
- the image appears off-color on the camera,
- the thumbnail is off-color,
- the embedded JPEG is useless,
- you can not reasonably combine raw with in-camera JPEG
[a href=\"index.php?act=findpost&pid=155997\"][{POST_SNAPBACK}][/a]
If I'm shooting RAW, I don't care about the appearance of the jpeg based image on the camera's LCD screen. I'm only concerned about the correct exposure.
If I were really fanatical about getting the mximum exposure my camera is capable of, short of clipping one or more of the channels, I'd adopt John Sheehy's method of using a particular type of color filter on the lens to equalise the sensitivity of the camera's red, green and blue pixels.
I always use the camera's auto WB. If for some reason, as is sometimes the case, that doesn't appear quite right in the ACR window, I'll make adjustments before converting. Sometimes simply selecting the 'flash' WB instead of the 'As shot' WB in ACR does the trick, if the image was shot using flash. Sometimes I mess around with the temperature and tint slider or try a gray balance.
I bought a gray card once, but never used it. I had some idea I would take 2 shots, the first with a big gray card in the scene and the second shot without it. But it's not really my style of shooting, waving a gray card around .
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If I were really fanatical about getting the mximum exposure my camera is capable of, short of clipping one or more of the channels, I'd adopt John Sheehy's method of using a particular type of color filter on the lens to equalise the sensitivity of the camera's red, green and blue pixels
I did not know about that, but I am waiting for the arrival of a magenta filter (delivery time: 6-10 weeks), just for this purpose.
The wast majority of my shots (landscape panos) are "green limited. I hope to gain almost half stop this way.
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Well, how is he supposed to know where the right is? How do you know where it is?
What kind of feedback is his camera giving?
Where is the clipping point in the P45+ RAW data?
Are the higher ISOs actually unique digitizations or just logistics?
It's pretty much a given that the camera histogram is bullshit, since no camera histogram yet is based on actual RAW data, but some conversion/interpretation of that data instead. To really know what the camera histogram is telling you, you need to conduct the test I outline toward the end of this article (http://www.visual-vacations.com/Photography/exposure_metering_strategies.htm). Shoot RAWs of a Color Checker or WhiBal card along with some of your favorite subject matter under your typical lighting conditions, starting about 2 stops under meter and increasing exposure in 1/3-stop increments until you're about 2 stops over the meter. Make a note of where the camera histogram first indicates clipping. Then look at the RAWs in ACR or the CryptoBola analyzer (or better yet, both) and see where clipping actually occurs in the RAW data.
Once you've done that, you'll know what your camera histogram really means, you'll know what the exposure interval between camera histogram clipping and RAW clipping really is, and you'll be able to judge exposure much more intelligently.
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I did not know about that, but I am waiting for the arrival of a magenta filter (delivery time: 6-10 weeks), just for this purpose.
The wast majority of my shots (landscape panos) are "green limited. I hope to gain almost half stop this way.
[a href=\"index.php?act=findpost&pid=156003\"][{POST_SNAPBACK}][/a]
Using a magenta filter in daylight will increase the DR of full-color response. It will not help with those cases where you can retrieve greyscale highlights from the red channel, however. You can exaggerate that benefit by using a green filter.
The magenta filter in daylight will make the shadow noise less chromatic. Same for tungsten; except you need a filter that cuts red and green about two stops relative to blue.
This all assumes you have enough light to get a good exposure with the filters. They don't really help if they force bad exposures.
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Axel,
Seeing you have a P45+, could you post some underexposed shots at hi iso please ?
Edmund
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Sure, no problem...
Here are some bracketed exposures at ISO 800 and ISO 400:
[a href=\"http://rapidshare.com/files/72455887/ISO800_Tests.zip]ISO 800[/url]
ISO 400 (http://rapidshare.com/files/72461839/ISO400_Tests.zip)
The images are taken with a Profoto B600R flash as the only light source, bounced on a umbrella (white from above.) They are the untouched RAW files from the Phase One P45+ back on a H2 camera using the HC100 lens.
If you push and pull the file a lot in PS, you will notice some lines in the black bag, but the adjustments have to be way over the top like in this screenshot:
[attachment=4035:attachment]
-axel
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These are less underexposed than Edmund's examples. The one with the lowest exposure of the ISO400 samples is only about 1 stop under. At least that is what ACR is telling me.
Pushing it towards the point of clipping does show the bag go mildly to magenta & greenish.
I bet when you would underexpose that shot another stop, with which you will come close to Edmunds example, there will be a lot more garbage in the bag.
I am currently downloading your ISO800 examples...
Yikes! The ISO800 examples look horrible. These are going from being exposed right on the point of clipping to being 3/4 of a stop over? Even than there is a lot of Green/magenta rubbish in the darker parts.
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These are less underexposed than Edmund's examples. The one with the lowest exposure of the ISO400 samples is only about 1 stop under.
[a href=\"index.php?act=findpost&pid=156155\"][{POST_SNAPBACK}][/a]
This is correct, there should be examples of both underexposure by between 2/3s and a full stop, as well as one correctly exposed, and one with highlights clipping in both of the downloads (ISO400/800).
If you take the correctly exposed 400 and 800 images, and pull back the midtones a lot, while clipping the blacks around 16-18 from zero, you can see striations in the 800 image, but not the 400. Anyone with knowledge as to why this would happen?
I'm content with the image quality as of yet for my usual ISO50-200 shots, but I'm seeing some magenta and green casts in some of my images shot against white product tables. I'll be looking closer at image quality as I get to know the back and software more.
-axel
EDIT:
Having seen over the files in ACR, zeroing everything, I now don't trust the histogram in C1 at all, they are completely different, with ACR pulling out a lot more highlight detail and C1 pushing midtones as well as highlights a lot, even using the "Linear" tone curve provided.
The image provided shows the differences. If somebody can show me a "secret button" in C1, it'd be greatly appreciated:
[attachment=4038:attachment]
EDIT II:
There are much larger differences between the ISO 400 and ISO 800 shots in ACR than in C1, I'm not sure what to trust... check out these histograms:
[attachment=4039:attachment]
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Last test of the day...
I did a quick test pushing the underexposed ISO 400 image up 0,8 on the exposure slider in C1. Exported the pushed underexposed ISO 400 image as well as a properly exposed ISO 800 image to 16 bit tiffs and opened both up in PS. I did an identical Levels adjustment on both to bring up any problems in the black bag. Check out the trouble in the ISO 800 image, whereas the ISO 400 image holds up much better and is by far preferable to the ISO 800 image (neither is great though....)
ISO 400 pushed +0,8 on top, ISO 800 correctly exposed on bottom. Levels adjustment shown as well:
[attachment=4040:attachment]
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Axel,
Thank you very much for posting these tests which are much more demonstrative than my own.
This raises the possibility that the issues with our P45+ might be a feature of every back of this type and not just ours.
To recap, the ISO 800 image shows some strong striping, similar to the issues I have seen in some of my own shots which I consider well exposed. They are there also in ISO 400 but more restrained. As for the color shifts, for street/lifestyle I think these might be dealt with by a special profile or color adjustments, or moving to black and white, but the stripes make a real mess of the image.
As you remark, C1 seems to be applying a strong curve, it might be interesting to try and determine what the "real" ISO of the back is at each setting.
Edmund
Last test of the day...
I did a quick test pushing the underexposed ISO 400 image up 0,8 on the exposure slider in C1. Exported the pushed underexposed ISO 400 image as well as a properly exposed ISO 800 image to 16 bit tiffs and opened both up in PS. I did an identical Levels adjustment on both to bring up any problems in the black bag. Check out the trouble in the ISO 800 image, whereas the ISO 400 image holds up much better and is by far preferable to the ISO 800 image (neither is great though....)
ISO 400 pushed +0,8 on top, ISO 800 correctly exposed on bottom. Levels adjustment shown as well:
[attachment=4040:attachment]
[a href=\"index.php?act=findpost&pid=156223\"][{POST_SNAPBACK}][/a]
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This is correct, there should be examples of both underexposure by between 2/3s and a full stop, as well as one correctly exposed, and one with highlights clipping in both of the downloads (ISO400/800).
Well, the raw files make quite different impressions; left side: ISO 400, right side: ISO 800 (the clipping point is still assumed to be 65535. The Phase One site states:
full 16 bit image data and Color depth: 16 bit per color
There is nothing even close to clipping, except if the bit depth is in fact 14 - but that's not probable.
Histogram comparison (http://www.panopeeper.com/Demo/Axel_001123-001129_hist.gif)
However, the underexposure is very low here.
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Panopeeper,
I am getting more and more intrigued by the relationship between the strongly underexposed histograms you show and the photographic reality of decently exposed images we are also seeing. There is an obvious disparity here, and it might be worth trying to figure out what's going on.
Edmund
Well, the raw files make quite different impressions; left side: ISO 400, right side: ISO 800 (the clipping point is still assumed to be 65535. The Phase One site states:
full 16 bit image data and Color depth: 16 bit per color
There is nothing even close to clipping, except if the bit depth is in fact 14 - but that's not probable.
Histogram comparison (http://www.panopeeper.com/Demo/Axel_001123-001129_hist.gif)
However, the underexposure is very low here.
[a href=\"index.php?act=findpost&pid=156270\"][{POST_SNAPBACK}][/a]
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There is an obvious disparity here, and it might be worth trying to figure out what's going on.
Well, Edmund, I have been telling you for days to make a *totally* overexposed shot (white board with +4EV), with different ISOs. This is important to see, if there is a non-linear range before the "ultimate clipping", or if a channel clips at once (there are examples for both).
Furthermore, you should shoot some well-lit scenery with a series of exposures 1/3 apart, up to +3EV compared to what you would do.
You can upload them with "yousendit". You can download Rawnalyze from from here (http://www.cryptobola.com/PhotoBola/free/rawnalyze.exe) and take a look at them yourself, but the manual is quite old; a new one will be ready in perhaps two weeks.
It is really a strange situation, that you (and not only you) have such an expensive equipment and don't know its limits.
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Both Edmund and Axel have their P45's only for a very short time now. What we are witnessing here is that they are trying to find the limits of their equipment I reckon
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Both Edmund and Axel have their P45's only for a very short time now. What we are witnessing here is that they are trying to find the limits of their equipment I reckon
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Hmmm... I could have agreed on this, yet my previous H3D has been run through it's paces by me, and it never showed anything like this. I have used it at ISO 400 a lot more than i initially thought I would, and even pushed images around a stop. I have never ever seen this type of striping from it (and I do have some tens of thousands of images from it...)
The files from the P45+ just don't seem to hold up as well to extensive adjustments in high ISO, and I believe it has something to do with the way C1 fools you to believe you have exposed to the right, while you are actually around a normal exposure or just below. I shoot mostly tethered, so frequently check the histogram to see if the exposure is correct.
I'm down with a cold, but I'll be re-checking some files from the H3D-39 to see if I can push them hard in a levels adjustment to bring out any kind of striations (when i come back to work, on thursday I hope...). Shame I don't still have the camera, to make a side by side.
Well, Edmund, I have been telling you for days to make a *totally* overexposed shot (white board with +4EV), with different ISOs. This is important to see, if there is a non-linear range before the "ultimate clipping", or if a channel clips at once (there are examples for both).
Furthermore, you should shoot some well-lit scenery with a series of exposures 1/3 apart, up to +3EV compared to what you would do.
You can upload them with "yousendit". You can download Rawnalyze from [a href=\"http://www.cryptobola.com/PhotoBola/free/rawnalyze.exe]from here[/url] and take a look at them yourself, but the manual is quite old; a new one will be ready in perhaps two weeks.
It is really a strange situation, that you (and not only you) have such an expensive equipment and don't know its limits.
[a href=\"index.php?act=findpost&pid=156282\"][{POST_SNAPBACK}][/a]
Well, for myself it does not really matter what you find as the limits of the equipment in "Rawnalyze", for myself what matters is if the software that makes the ultimate raw development from my file (C1) is showing highlight clipping in large portions of the image, then that is what constitutes "white clipping" and the limits of the equipment in actual use.
This using a linear tone curve, with no adjustments what so ever. The most overexposed images i uploaded in the post yesterday shows a completely "clipped" white table, losing large portions of the image in featureless white. I know ACR recovers all of this, but it is of little importance to me as a fast paced tethered shoot has no room for constant checking of the histogram in more than one app.
Attatched you will find an image of what is shown as clipped in C1 with the adjustments shown on the side.
[attachment=4043:attachment]
EDIT: I have a friend with a H3D-39, he is going to lend it to me for a quick test. So sometime during the week I hope to have a side by side. Maybe I'm off on this one, I't just odd that I have not noticed anything like this on my H3D, yet saw it immediately when testing the high iso on the P45+
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Axel,
The killer question is:
Are all the P45+ backs stripers, or are we the lucky few with broken ones ?
I mean, if everybody else wants to shoot ISO 50, fine with me, but if I like to shoot ISO 400 and 800, it seems to me I've paid enough for the privilege, and if Phase has a P45+ that does not stripe, that's the one I want to be using.
Edmund
Hmmm... I could have agreed on this, yet my previous H3D has been run through it's paces by me, and it never showed anything like this. I have used it at ISO 400 a lot more than i initially thought I would, and even pushed images around a stop. I have never ever seen this type of striping from it (and I do have some tens of thousands of images from it...)
I't just odd that I have not noticed anything like this on my H3D, yet saw it immediately when testing the high iso on the P45+
[a href=\"index.php?act=findpost&pid=156369\"][{POST_SNAPBACK}][/a]
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Edmund,
I think it's hard to say if you really have a broken back.
Lot of guy here asked you to post a well expose image to see how it looks.
Because so far the one you did post were 1 3/4 stop underexp. I could have missed some.
So set your tripod up, get the shot, overexposed it and narrow down til you are as close as possible to the good one.
Otherwise send me your back I'll do it for you. I pay for the Fedex.
But if I like the result I may keep it...
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Are all the P45+ backs stripers, or are we the lucky few with broken ones ?
[a href=\"index.php?act=findpost&pid=156493\"][{POST_SNAPBACK}][/a]
Hi Edmund,
Yes, this is a question I really want answered (and if anyone out there with a P45+ want to take the time, do a quick test and post your raws!)
Also, my ISO800 files (posted earlier) has a properly exposed (according to ACR) shot, with clearly visible lines of magenta in the black bag (attatched with levels on top...) The image is unaltered, and opened with ACR where everything has been zero'ed.
This type of behaviour in a P45+ is not what I am looking for. If P1 wants to market the back as ISO800, then lines in properly exposed images, should not appear, no matter what ISO. Grain is fine, lines are not. I don't see the need for you to post other examples as some posters are asking for. The lines are in your back, as well as mine, and my test shot is exposed properly using ETTR as a guide. If this is not good enough, then what is?
Also there is a discrepancy between the way C1 shows histograms, and what the actual exposure is, this is an issue worthy of its own topic...
-axel
[attachment=4052:attachment]
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my bad edmund didn't pay attention to gotfred post.
have you sent images to phase?
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my bad edmund didn't pay attention to gotfred post.
have you sent images to phase?
[a href=\"index.php?act=findpost&pid=156515\"][{POST_SNAPBACK}][/a]
No ones bad really
I intend to, but feel the need for further testing and experience with the back so that I can answer any question they might want to know from me (P1 that is...)
Also I want to test it against the H3D on iso400 before I send it away. If I find striping in the P45+ when pushing slightly, and not in the H3D, then there is reason for concern, particularly as this is touted as an ISO800 back and should hold its own against the H3D.
I'm sure both me and Edmund will keep everyone updated!
-axel
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Also, my ISO800 files (posted earlier) has a properly exposed (according to ACR) shot, with clearly visible lines of magenta in the black bag (attatched with levels on top...) The image is unaltered, and opened with ACR where everything has been zero'ed.
[a href=\"index.php?act=findpost&pid=156508\"][{POST_SNAPBACK}][/a]
I can't see any major problem here, Axel. Is this a storm in a teacup?
I don't see any magenta striping in the black bag when I convert in ACR, although there is a bit of noise in the darkest parts of the bag and a very slight magenta cast which is typical of deep shadows with my Canon DSLRs at any ISO.
If this sort of thing were going to be a problem in the final balance of the image, ie. if you wanted to really bring out the shadows, then just a little more exposure would probably fix it. As it is, you're using a pretty conservative ETTR in the shot with the greatest exposure out of the 3 bracketed shots at ISO 800.
I had a look at the specral highlights on the tangerine (after recovering highlights to the maximum in ACR) and they have a value around, 207,197,185.
I think you could probably have given that shot at least another 1/3rd of a stop more exposure.
[attachment=4056:attachment] [attachment=4057:attachment]
The problem with ETTR as I see it, is it's better to be underexposed by 1/3rd of a stop than overexposed by 1/3rd of a stop. However, when bracketing exposures, one can afford to be less conservative.
Of course there are certain situations where bracketing is not possible as in the case of this shot of a Hill Tribe woman in Chiang Mai, taken with flash late in the evening. I made an assessment from the 5D's histogram that the exposure was probably okay. In fact, I believe there is slight clipping of highlights but nothing serious. However, I would have preferred a 1/3rd stop less exposure.
The default setting in ACR gives an impression the image is seriously clipped in the highlights. [attachment=4058:attachment]
However, just one click on the 'auto' button produces an almost acceptable result which looks hardly overexposed at all. [attachment=4059:attachment]
There's still scope in ACR to recover more highlight detail here. The brightest part of the image (apart from specral highlights) appears to be the yellowish tea shirt with a value around 207,197,185 after maximum highlight recovery. [attachment=4060:attachment]
Do you think this image is overexposed?
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I don't see any magenta striping in the black bag when I convert in ACR, although there is a bit of noise in the darkest parts of the bag and a very slight magenta cast which is typical of deep shadows with my Canon DSLRs at any ISO.
[a href=\"index.php?act=findpost&pid=156581\"][{POST_SNAPBACK}][/a]
On my calibrated Eizo, I see magenta lines in the black bag. They are fairly wide, and not uniform in shape as they run along the bag horizontally. Of course, if i wanted i could pull the bag further down slightly (from around the 25-35 area its in now, to around 15-25). And have no problems in print or on screen. But to me this is not the issue, if i wanted to bring the shadows out, using S/H for example, then the lines quickly become an issue, and something I'm not used to from my H3D. As i said, grain is ok, lines are not. (On my Macbook Pro I don't see the lines clearly at all...)
The problem with ETTR as I see it, is it's better to be underexposed by 1/3rd of a stop than overexposed by 1/3rd of a stop. However, when bracketing exposures, one can afford to be less conservative.
[a href=\"index.php?act=findpost&pid=156581\"][{POST_SNAPBACK}][/a]
I agree totally with you on this. I can not afford to bracket in my shooting and have to trust my light meter and my histogram, it's ofthen fast paced, and I'm trying to capture a certain facial expression and body posture in non-professional models. It's (almost) always tethered and therefore C1 is the app to do this in, not ACR.
There's still scope in ACR to recover more highlight detail here. The brightest part of the image (apart from specral highlights) appears to be the yellowish tea shirt with a value around 207,197,185 after maximum highlight recovery. [attachment=4060:attachment]
Do you think this image is overexposed?
[a href=\"index.php?act=findpost&pid=156581\"][{POST_SNAPBACK}][/a]
Yes I think this image is overexposed, but you do a good job at recovering it. I did a yoga shoot the other day, against a white backgound, where parts of the models outfit was white. Exposing to this level of accuracy to the right is just not a safe undertaking and can lead to a lot of retoutching that is not within the scope of the agreement between photographer and client. I understand the argument fully though, just don't think P1 should demand this from their customers in order to get an acceptable result form such an expensive piece of equipment.
I did some portraits of Alan Greenspan together with a Norwegian client the other day, and as flash was not permitted, as well as being given a 5 minute timeframe for both makeup/styling and shooting, where the space allowed (due to security) for shooting is behind the scene of a theatre where everything is black, black, and blacker than black. I used two 1000watt tungsten Pro heads with 2x3 softboxes slightly from above, this gave me around f3.5 at 1/80 with ISO200. I just did not dare use ISO400 or 800. With the black background, the poor light (tungsten balanced) the black suits, etc. I don't do this ofthen, but expect my P1 back to handle it better than my Canon when it does come along. (Maybe I should have chosen my canon and a 35 f1.4... )
Storm in a teacup it may be, and as I said, I'll probably eat my own words when I test against the H3D-39
-axel
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I am tired of this "underexposed" mantra by the studio crowd here.
When one does real-world work, without fill flash, as opposed to studio, deep shadows are always underexposed. And in the real world one doesn't bracket or ETTR, one just sets the camera on full--auto and hopes for the best. Which is why we have full AF and AE cameras.
Here are two examples of what I enjoy doing:
1. Fashion shows: The girls are on the stage in the light. As I tend to image from strange positions around the room, the audience and background are often in my pictures as a backdrop, in the same shot, and they are way, way underexposed. DO I NEED TO GIVE THIS UP ?
2. City night images: Go to Times Square, Shibuya, the Champs Elysées or any other city night scene, and the shadows in my image will often be way underexposed, even if the interesting parts of the image are correct. DO I NEED TO GIVE THIS UP ?
So a back which stripes whenever there are deep blacks in an image will stripe quite often outside the studio.
My own experience is that my P45+ stripes quite predictably when I take pictures indoors of trendy people (eg. photographers) who like to wear black sweaters, jackets and pants. I switch to ISO 800 or 400, take a good available light image with the camera set on auto-everything, and then one can already see some stripes in the clothes they are wearing.
Edmund
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DO I NEED TO GIVE THIS UP ?
Edmund
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=156606\")
Yes and no
With the shadows in in the unlit areas of say a fashion show where you have exposed for the girl
a deep S in the toe of the curve will make those areas go dark and reduced the affect of noise while darkening them
same for black jumpers
You clould use auto everything on +1 epx comp setting
But pulling underexposed files up - yes - give it up and buy a D3
NOW you may have a broken 'back I think you need to do side by side tests with your dealer to prove that
also you might like to read and comment on my other thread [a href=\"http://luminous-landscape.com/forum/index.php?showtopic=21246]ISO[/url]
S
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Euh....
I do a lot of shots outside the studio and never have my camera on full auto. I try to because some little voice inside me says it might be better but I just want to have that feeling of control.
The audience you are talking about, do you lift that area? I would normally burn things like that away in which case weird stuff in the shadows are no problem. Having said that the only times I do catwalk shoots I don't bring my MFDB but the Nikon (while wishing for something like a 5D )
The second example, again you don't lift the shadows most of the time don't you? Having said that, again I find MFDB not the best tool for doing night shots unless you put it on a tripod and massage until you get it exactly right.
These things are naturally the way I work but from the things you like to be doing I get the feeling that you were expecting performance more like the Canon? Which it isn't (as you have found out).
On the other hand you & Axel might have lemons.
I see Sam already said basically the same thing
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I see Sam already said basically the same thing
[a href=\"index.php?act=findpost&pid=156608\"][{POST_SNAPBACK}][/a]
No . exactly the same thing
S
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I am tired of this "underexposed" mantra by the studio crowd here.
When one does real-world work, without fill flash, as opposed to studio, deep shadows are always underexposed. And in the real world one doesn't bracket or ETTR, one just sets the camera on full--auto and hopes for the best. Which is why we have full AF and AE cameras.
Here are two examples of what I enjoy doing:
1. Fashion shows: The girls are on the stage in the light. As I tend to image from strange positions around the room, the audience and background are often in my pictures as a backdrop, in the same shot, and they are way, way underexposed. DO I NEED TO GIVE THIS UP ?
2. City night images: Go to Times Square, Shibuya, the Champs Elysées or any other city night scene, and the shadows in my image will often be way underexposed, even if the interesting parts of the image are correct. DO I NEED TO GIVE THIS UP ?
So a back which stripes whenever there are deep blacks in an image will stripe quite often outside the studio.
My own experience is that my P45+ stripes quite predictably when I take pictures indoors of trendy people (eg. photographers) who like to wear black sweaters, jackets and pants. I switch to ISO 800 or 400, take a good available light image with the camera set on auto-everything, and then one can already see some stripes in the clothes they are wearing.
Edmund
[a href=\"index.php?act=findpost&pid=156606\"][{POST_SNAPBACK}][/a]
Do you want those dark parts in your final image to stay in the dark or not... If yes no trouble... if you want to bring this part of the image up to the point it doesn't look underexp. you'll find noise and everything you have experienced.
It,s a little bit too TK for me in English to express my thought I'll PM you in french
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I am tired of this "underexposed" mantra by the studio crowd here.
When one does real-world work, without fill flash, as opposed to studio, deep shadows are always underexposed. And in the real world one doesn't bracket or ETTR, one just sets the camera on full--auto and hopes for the best. Which is why we have full AF and AE cameras.
Here are two examples of what I enjoy doing:
1. Fashion shows: The girls are on the stage in the light. As I tend to image from strange positions around the room, the audience and background are often in my pictures as a backdrop, in the same shot, and they are way, way underexposed. DO I NEED TO GIVE THIS UP ?
2. City night images: Go to Times Square, Shibuya, the Champs Elysées or any other city night scene, and the shadows in my image will often be way underexposed, even if the interesting parts of the image are correct. DO I NEED TO GIVE THIS UP ?
So a back which stripes whenever there are deep blacks in an image will stripe quite often outside the studio.
My own experience is that my P45+ stripes quite predictably when I take pictures indoors of trendy people (eg. photographers) who like to wear black sweaters, jackets and pants. I switch to ISO 800 or 400, take a good available light image with the camera set on auto-everything, and then one can already see some stripes in the clothes they are wearing.
Edmund
[a href=\"index.php?act=findpost&pid=156606\"][{POST_SNAPBACK}][/a]
Do you want those dark parts in your final image to stay in the dark or not... If yes no trouble... if you want to bring this part of the image up to the point it doesn't look underexp. you'll find noise and everything you have experienced.
It,s a little bit for me in English to express my thought I'll PM you in french
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Here's a link to a Raw file EXPOSED TO THE RIGHT at 400 ISO, in DAYLIGHT.
http://download.yousendit.com/D9E8BE575BC4D993 (http://download.yousendit.com/D9E8BE575BC4D993)
Push it through C1 3.77 with no adjustments and you will be able to see a light line just under the stem of the pear, leading to the right. The streaking I complain about is present but less noticeable with normal exposure, but a fashion person, or color consultant will see it immediately.
Edmund
[a href=\"index.php?act=findpost&pid=155443\"][{POST_SNAPBACK}][/a]
Edmund,
I know I am getting into this a little late, but I processed your file in C1 3.7.7 and also saw the line you described. I then processed it in C1 4 and the line just below the stem of the pear disappeared, only to be replaced by another artifact (magenta line) below the body of the pear. I then processed it in Raw Developer 1.7.1 and all artifacts disappeared. All processing was pushed to the right just to the point of highlight clipping.
Victor
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Do you want those dark parts in your final image to stay in the dark or not... If yes no trouble... if you want to bring this part of the image up to the point it doesn't look underexp. you'll find noise and everything you have experienced.
It,s a little bit for me in English to express my thought I'll PM you in french
[a href=\"index.php?act=findpost&pid=156675\"][{POST_SNAPBACK}][/a]
David,
You wonder whether I would want more detail in those shadows and want to push or lift the image there. The answer is no, the shadows are for me exposed just right, I want them to stay dark, and they should stay dark after processing or retouching. Dark does not mean totally featureless, when I do USM I will get some slight detail there eg. texture in the dark cloth, or some dark out of focus figures in the unlit background of a fashion show.
To summarize I do want these dark parts to sink *gracefully* into the shadows - I don't need or expect many details there - and I don't want lines or artefacts there although grain and noise are quite ok.
Edmund
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The H3D-39 vs. P45+ ISO400 test, as promised!
And also as promised I'll eat my words
Both images using the same lens (100mm f2.2) P45+ on a H2 body, focus distance is the same, and the cameras where tripod mounted with mirror up. Same exposure for both (f5.6, 1/80).
Everything is zeroed in every software (C1, Flex, ACR.) Every software is latest non-beta version. Each image has its own histogram pasted on top... The same levels type adjustment to bring out any problems is used.
I'll make raw files available in a couple of days to those who would like them... (please say so on the board, if there are fewer than 1 taker, I won't go to the trouble.)
enjoy. -axel
[attachment=4066:attachment]
EDIT: The hassy file has to go through .dng conversion to be operable in ACR, this loses a lot of the hassy data like color accuracy etc. (or so hassy claims... and is correct in my experience with different hassy systems over the last couple of years.)
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At first glance the Hassy file has streaks ???
Edmund
The H3D-39 vs. P45+ ISO400 test, as promised!
And also as promised I'll eat my words
Both images using the same lens (100mm f2.2) P45+ on a H2 body, focus distance is the same, and the cameras where tripod mounted with mirror up. Same exposure for both (f5.6, 1/80).
Everything is zeroed in every software (C1, Flex, ACR.) Every software is latest non-beta version. Each image has its own histogram pasted on top... The same levels type adjustment to bring out any problems is used.
I'll make raw files available in a couple of days to those who would like them... (please say so on the board, if there are fewer than 1 taker, I won't go to the trouble.)
enjoy. -axel
[attachment=4066:attachment]
EDIT: The hassy file has to go through .dng conversion to be operable in ACR, this loses a lot of the hassy data like color accuracy etc. (or so hassy claims... and is correct in my experience with different hassy systems over the last couple of years.)
[a href=\"index.php?act=findpost&pid=156740\"][{POST_SNAPBACK}][/a]
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At first glance the Hassy file has streaks ???
[a href=\"index.php?act=findpost&pid=156747\"][{POST_SNAPBACK}][/a]
Yes, and nice greenish spots...
To me the P45+ came out as having a slightly lower dynamic range (very, very, very slightly.) But I guess Panopeeper should get his +4 stop shots soon and we can all get the numbers out all solid and shiny! (anyone up for this, I was supposed to do them, but forgot!) And now the nice H3D-39 is on its way back...
-axel
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Ok, so we guys with Kodak chips had better find a workaround.
Could you please yousendit.com the Raws ?
Edmund
Yes, and nice greenish spots...
To me the P45+ came out as having a slightly lower dynamic range (very, very, very slightly.) But I guess Panopeeper should get his +4 stop shots soon and we can all get the numbers out all solid and shiny! (anyone up for this, I was supposed to do them, but forgot!) And now the nice H3D-39 is on its way back...
-axel
[a href=\"index.php?act=findpost&pid=156755\"][{POST_SNAPBACK}][/a]
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Could you please yousendit.com the Raws ?
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=156758\")
Here are the raws:
[a href=\"http://download.yousendit.com/0D3CED025512EFCC]http://download.yousendit.com/0D3CED025512EFCC[/url]
-axel
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The stripes move around with different Raw software, so a workaround should be possible - I've sent Brian of Raw Developer an email, maybe registered users or otthers would find it useful to send him a note or a bounty note too. I think he might be in a good position to solve this or at least tell us exactly what's going on.
Edmund
Here are the raws:
http://download.yousendit.com/0D3CED025512EFCC (http://download.yousendit.com/0D3CED025512EFCC)
-axel
[a href=\"index.php?act=findpost&pid=156782\"][{POST_SNAPBACK}][/a]
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The hassy file has to go through .dng conversion to be operable in ACR, this loses a lot of the hassy data like color accuracy etc. (or so hassy claims... and is correct in my experience with different hassy systems over the last couple of years.)
Whose DNG converter is that? Is it their own production? Where is that to get from?
I can do nothing with the .FFF file. I don't know the format (it is in a TIFF container, but that's not enough). Adobe's DNG converter can't process it (of course; if it could, then ACR would accept it as well).
Anyway, it sounds to be unbelievable, that the DNG conversion loses image data. Color accuracy is no separate information in the raw image, it can not be "lost". There may be another problem: the in-factory calibration of ACR is less than optimal for several cameras. It can be calibrated to yield matching color, or anything you want to. Those, who are very picky about colors, calibrate their camera themselves, because there can be small variations between copies of the same model.
Another problem may be, that their DNG converter generates incorrect color conversion values (in the DNG file).
I guess Panopeeper should get his +4 stop shots soon and we can all get the numbers out all solid and shiny!
I took another look at your previously posted raw images and found green pixels with the value 65536 (on the specular top edge of the Toblerone). Not many, only 3400 of them; that is is 0.0022%, too few to be shown by the histogram.
Still, this proves, that the sensor in fact delivers 65536 levels in ISO 400. Consequently the top level in the newer image, 001136, namely 15000 is still two stops from clipping:
Histogram of 001136 (http://www.panopeeper.com/Demo/Axel_001136_hist.gif)
As the counters show, there are only about 2200 pixel over 15000, that's negligable.
Now, what does this mean in the praxis?
1. 18.7% of all pixels in 001136 are in the range 0-127. If we start at the right end (i.e. with the range of levels from 32768 to 65535) as +0EV, then the range 0-127 corresponds to -9 EV.
2. This shot is not so bad, but Edmund's CF000965 had 10.5% of all pixels with value zero (his other posted shot had 64%).
Now, Edmund may say that this is not a problem for him, he does not want to see details in the deep shadows, only graceful noise. However, this is not so simple. The proportion of the values of the three "kind" of pixels makes the color (with de-mosaicing, of course); this is obvious. What is perhaps not so obvious is, that when one or two colors are on level zero, then the proportion is gone to the dog: on one place it may be (0, 50, 80), on an even darker spot with half the lightness (0, 25, 40). In other words, different shades of the same color can result in vastly different colors. This can appear as color noise, which may be acceptable, typically on very fine structured surface like fabric/cloth, but it may manifest as off-color spots as well.
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Whose DNG converter is that? Is it their own production? Where is that to get from?
[a href=\"index.php?act=findpost&pid=156845\"][{POST_SNAPBACK}][/a]
It is a function of Flexcolor to export DNG's. Hasselblads info on this (anyone correct me if im wrong) is that there are headers and exif fields in the .3FR files (the backbone, before they become .fff) containing vital info for the use of DACII, its file correction software. Also I believe Flexcolor downloads some sort of "black-subtraction frame" or similar from the back of each camera being attatched to it. This does not follow through to other apps, consequently not applying all possible file corrections.
Personally I don't know if any of this is correct, but I have through my some ten thousand files with the H3D tried .dngs several times to recover highlights, and the images have had more noise and other problems not seen in Flex.
-axel
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The H3D-39 vs. P45+ ISO400 test, as promised!
And also as promised I'll eat my words
Both images using the same lens (100mm f2.2) P45+ on a H2 body, focus distance is the same, and the cameras where tripod mounted with mirror up. Same exposure for both (f5.6, 1/80).
Everything is zeroed in every software (C1, Flex, ACR.) Every software is latest non-beta version. Each image has its own histogram pasted on top... The same levels type adjustment to bring out any problems is used.
I'll make raw files available in a couple of days to those who would like them... (please say so on the board, if there are fewer than 1 taker, I won't go to the trouble.)
enjoy. -axel
[attachment=4066:attachment]
EDIT: The hassy file has to go through .dng conversion to be operable in ACR, this loses a lot of the hassy data like color accuracy etc. (or so hassy claims... and is correct in my experience with different hassy systems over the last couple of years.)
[a href=\"index.php?act=findpost&pid=156740\"][{POST_SNAPBACK}][/a]
First question... Why did you choose a non-standard set-up in FlexColor when you shot and also saved the image? In both cases the "Film Response" curve is set to "Low Contrast" instead of "Standard or "Linear". Seems an odd choice. I've never used it for any image.
Second question... What is the point of this exercise of crushing and destroying image data and quality with radical compression and gamma settings? It does show that you can create image problems that would not exist otherwise, but other than that what are we learning?
I've attached a png file (from the H3D RAW) that has zero noise bias or color noise setting. It simply has a standard film response setting and the black point set to the most conservative end point.
[attachment=4075:attachment]
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Edmund is going to say "how really astonishing that we have total zero values in an image file!"
That piece of cloth was imaged on an average Paris day, in room light where I could clearly see. There is texture to be seen on the cloth. No way the physics of the situation could push all those pixels on the cloth down to absolute zero.
Some sort of firmware cleanup seems to be going round and doing some sweeping up here, methinks.
Edmund
2. This shot is not so bad, but Edmund's CF000965 had 10.5% of all pixels with value zero (his other posted shot had 64%).
Now, Edmund may say that this is not a problem for him, he does not want to see details in the deep shadows, only graceful noise. However, this is not so simple. The proportion of the values of the three "kind" of pixels makes the color (with de-mosaicing, of course); this is obvious. What is perhaps not so obvious is, that when one or two colors are on level zero, then the proportion is gone to the dog: on one place it may be (0, 50, 80), on an even darker spot with half the lightness (0, 25, 40). In other words, different shades of the same color can result in vastly different colors. This can appear as color noise, which may be acceptable, typically on very fine structured surface like fabric/cloth, but it may manifest as off-color spots as well.
[a href=\"index.php?act=findpost&pid=156845\"][{POST_SNAPBACK}][/a]
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Good point Tech Talk!
Also if you look at the crest of the tape measure the blacks are much smoother on the H3D, in FlexColor and also in ACR but not as pleasing.
Still looks cleaner than the P45 though.
Jo S.x
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A couple of 100% crops from the previous image. The 100mm "H" lens is a stunning performer. I've always enjoyed using it. I like the reflections of the tape measure rule lines in the base of the orange.
[attachment=4076:attachment] [attachment=4077:attachment]
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First question... Why did you choose a non-standard set-up in FlexColor when you shot and also saved the image? In both cases the "Film Response" curve is set to "Low Contrast" instead of "Standard or "Linear". Seems an odd choice. I've never used it for any image.
[a href=\"index.php?act=findpost&pid=156877\"][{POST_SNAPBACK}][/a]
Sorry, my bad! I have inadvertently used my "low contrast profile" in flex instead of setting from the default (where i knew id get something else than ProfotoRGB as the profile. Linear should be the right choice (I'll refresh my old post during the week with this setting.)
Second question... What is the point of this exercise of crushing and destroying image data and quality with radical compression and gamma settings? It does show that you can create image problems that would not exist otherwise, but other than that what are we learning?
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The point of this exercise for me, was to verify at what limit I would have to retouch heavily if i underexposed using high ISO shots (low iso has never been a problem.) ISO800 on the P45+ is a lot worse than 400, yet as the H3D does not go to 800 yet, the test was at 400 to look for ANY striations and compare for reference to a faulty P45+, not to give any camerasystem any type of poor performance rating (they are both excellent.)
The test has for me shown that I can not (in any similar way) utilize the same high dynamic range to recover faulty (underexposed) images as I have done on some occasions with ISO50-100 shots, whithout a penalty of some magenta casts/lines. These do not appear at lower iso, and i can "pull out the shadows" to a much greater extent.
-axel
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The test has for me shown that I can not (in any similar way) utilize the same high dynamic range to recover faulty (underexposed) images as I have done on some occasions with ISO50-100 shots, whithout a penalty of some magenta casts/lines. These do not appear at lower iso, and i can "pull out the shadows" to a much greater extent.
-axel
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I don't think that taking a properly exposed image and then throwing out a huge amount of levels in the mid-tone to shadow range is a good way to simulate what can be recovered in an underexposed image. You might want to duplicate your experiment by actually under exposing at whatever ISO you want to test.
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A couple of 100% crops from the previous image. The 100mm "H" lens is a stunning performer. I've always enjoyed using it. I like the reflections of the tape measure rule lines in the base of the orange.
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I completely agreen on the performance of this lens, I had around 10000 exposures on it when I checked a couple of months back, and it has not failed me in any situation yet. I find all my lenses top notch (35, 100, 120 and 210) but don't like the 35 a lot, maybe because I have never been very good at wide angle shots...
I don't think that taking a properly exposed image and then throwing out a huge amount of levels in the mid-tone to shadow range is a good way to simulate what can be recovered in an underexposed image. You might want to duplicate your experiment by actually under exposing at whatever ISO you want to test.
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I don't either, but if you follow my other posts, you will see that I have posted underexposed raw files from the P45+. The last test between the H3D-39 and P45+ was a continuation of this mainly for my own personal interest and to see if the P45+ had a fault. (I had never experienced any striations like this on my H3D, so had to see for myself, guess I just don't underexpose much )
Using linear (that I now found out i did not do!) was to make the comparison as equal as possible in the black's, as C1 has a very aggressive tone curve, and nothing in between. This would render subsequent comparison with levels in PS useless. (It might be useless anyway, but for myself I found out a couple of things along the way )
A really, really important thing this has shown me, is how much C1 does before you even start editing, this is the opposite approach when compared to Flexcolor, and one that I don't fancy. I'd rather add than subtract in my image editing.
Also if you look at the crest of the tape measure the blacks are much smoother on the H3D, in FlexColor and also in ACR but not as pleasing.
Still looks cleaner than the P45 though.
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+1
-axel
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It is a worry, isn't it! . We all know that MFDBs are not too hot at high ISO. That means, if you want to get decent shadows, you've got to push the exposure to it's maximum and perhaps blow a few largish specral highlights which you otherwise wouldn't.
I don't see any rocket science here. There has to be at least some QC variation in DB quality from copy to copy. I exchanged my first copy of my 5D because I thought banding was unacceptable in deep shadows. But I have to admit, the image that first brought the problem to my attention was slightly underexposed.
The second copy was, I thought, marginally better regarding shadow banding but it seemed clear to me that the first camera was not really faulty. It was just an example of QC variation which one can sometimes come across in lenses. Nothing's perfect.
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Edmund is going to say "how really astonishing that we have total zero values in an image file!"
Well, 10% is not astonishing (though the 64% is), but it is strongly underexposed in my books.
There is texture to be seen on the cloth. No way the physics of the situation could push all those pixels on the cloth down to absolute zero
Pleeeze Edmund, I mentioned 10.5%, not all those pixels. See the figures for the following selection (marked by red rectangle):
crop from CF000965 (http://www.panopeeper.com/Demo/Edmund_CF000965_crop1.gif)
Btw, this one shows, that there is no pixel over 7600; this is for the entire image, not for the selection. 7600-15200-30400-60800, it is over three stops from the right edge, 65535.
If you expose it two stops higher and reduce it in post proc to the same darkness, it can "gracefully" sink into black without that much color noise.
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I completely agreen on the performance of this lens, I had around 10000 exposures on it when I checked a couple of months back, and it has not failed me in any situation yet
This is not the current subject, I would not have mentioned it, but I noticed something interesting on these shots. Following are 100% crops from three of your posted raw images. 001127 is the ISO 800 shot; all three are sharper, than the ISO 400 shots. The difference is observable on other parts as well.
What you see on these crops is not only unsharpened but not de-mosaiced, each pixel on its own (strongly green, for not not even white balanced). Only the sensor and the AA filter are between the lens and these crops.
Crops from 001123, 001124 and 001127 (http://www.panopeeper.com/Demo/Axel_001123-001124-001127_sharpness.jpg)
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This is not the current subject, I would not have mentioned it, but I noticed something interesting on these shots. Following are 100% crops from three of your posted raw images. 001127 is the ISO 800 shot; all three are sharper, than the ISO 400 shots. The difference is observable on other parts as well.
What you see on these crops is not only unsharpened but not de-mosaiced, each pixel on its own (strongly green, for not not even white balanced). Only the sensor and the AA filter are between the lens and these crops.
Crops from 001123, 001124 and 001127 (http://www.panopeeper.com/Demo/Axel_001123-001124-001127_sharpness.jpg)
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Is this not a function of wider DOF? The one extra stop closes down the aperture more and has a large impact at such a close focusing distance?
-axel
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Is this not a function of wider DOF? The one extra stop closes down the aperture more and has a large impact at such a close focusing distance?
I forgot that 100mm on your camera means a much wider FoV than on the APS-C sensor of my camera. With a 100mm lens I would have to go much farther away (85mm is already a tele lens for me).