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Author Topic: What happened to "CCD is better than CMOS"?!  (Read 62434 times)

eronald

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Re: What happened to "CCD is better than CMOS"?!
« Reply #60 on: January 16, 2016, 06:53:26 pm »

I understand that a warming/cooling filter could balance the R/G/B/G2 channels, but then again even for a straight skyline you still have to deal with any cloud higher than the sun. Also it requires an LCC shot to be made to really correct the color casts of the color filter.

Yunil - yes it is a pain. But the result is that the channels are now balanced you gain DR "for free". Every bit of mismatch is one bit DR you won't get. Take a shot at home under a simple incandescent lightbulb and you'll see what I mean. I think Iliah Borg pushed an extreme calculated version of this as UniWB, but I'm not very good with numbers so I think just a couple of filters in the bag will be all gain.

Edmund
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eronald

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Re: What happened to "CCD is better than CMOS"?!
« Reply #61 on: January 16, 2016, 06:59:37 pm »

Christoph,

I'm dumb - what color is the tearoff sheet in the view camera really? Green or yellow?  Is it fluorescent?
Reflections can be hard because they can be polarised ...

Edmund

As I said: Show me two files that were shot with the lowest ISO setting at a normal exposure time, then we'll see if there's any real difference :)

I know that a longer exposure and higher ISO doesn't work well on CCD chips - but have you ever considered that not everyone takes 60s exposures with ISO 200 or 400 on a daily basis?

If the image quality on ISO 50/100 is pretty much the same then I doubt most of 'us' would consider upgrading to a CMOS back if they never use such a long exposure time and/or a high ISO. Personally I shoot most landscape stuff at ISO50-100 and my longest exposures take between 5-10s and my usual print size is either 50x40cm or 80x60cm / 20x16 and 32x24inches.
Is there a real big discernible benefit for me? I doubt that.
Is there a real big discernible benefit for most users of the current CCD backs? I doubt that too.

Or course there are people who'll need it, people who take very long exposures at night or people who want to shoot portraits outside during the early dawn and the late dusk - whatever the reason there are people who might actually need it. But not everyone because it's not better in every situation. Your last comment highlights exactly that.
If you weren't keen on those super-long exposures a CCD would do perfectly well.

The issue you're describing is less due to the max possible Dynamic Range with the sensor but more due to its bad performance with long exposures.

Also I think I do see some strange issues with colours that are between yellow and green - it seems that CMOS doesn't capture greens as well but had the tendency to favour reds and yellows (see below). I think that's very interesting because here you can find a similar issue with the sensor in the Canon CMOS:
https://www.photigy.com/canon-5d-mark-ii-and-phaseone-p25-does-a-physical-sensor-size-make-a-difference/

Also weak on greens but stronger on yellows and reds, it doesn't look balanced and you get a similar result form the 50mpx and 100mpx CMOS sensor... when you look at the tripod in the left corner it's very strong, almost over-saturated - while the green sheet in the window looks very pale and almost mint-green. The IQ380 delivers a more neutral tripod-colour and a saturated green sheet - also the reflection in the 100% crop is much more on the green side while both CMOS-chips 'see' it as yellow.

Again you might think that the problem in on the side of the IQ380 but it's strange that the same effect appears when you compare an old CCD back to a newer CMOS sensor (like in the link above) and the flower was indeed more green than yellow.

Would it be at all possible to correct that with a colour profile or would that mess with the yellow tones overall?
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JoeKitchen

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Re: What happened to "CCD is better than CMOS"?!
« Reply #62 on: January 16, 2016, 07:36:44 pm »

Oh dear Lord, here comes the graphs agains.  Please help me. 

Is the DR range of the new sensors amazing?  Absolutely!  However, when I look at images utilizing the full DR of the sensor, I am more amazed at the technology, not so much with the image itself. 

Photography is about light and shadow, highlights and contrast!  I long for the days of working with B&W film printed on silver rich B&W warm toned paper, toned to completion with selenium.  Ohhhh my, the blacks ... and don't get me started with Platinum printing ...

But to edit a image to where the contrast is not that great is ... meh ...

Just because we have the ability to show everything, does not make the image better.  It is knowing what to show and how to use the light that really makes an image great. 

Well anyway, back to the studio.  Here's a quick rough edit of a Bourbon Neat I shot with my inferior P45+.  And yes, those highlights are completely gone, non-recoverble, but that is how I wanted, plus it look more impactful! 
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Wayne Fox

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Re: What happened to "CCD is better than CMOS"?!
« Reply #63 on: January 16, 2016, 07:51:57 pm »

to my recollection the thread title seems to focus on only a single point out of what was the original discussion which wasn't about CCD vs CMOS but was about  the supposed "medium format look".  CCD vs Cmos was only one element of that discussion which was theorized by some as one of the reason for the supposed "difference".

No need to resurrect it, just thought I'd mention it.  To me it's always been about resolution and the ability to oversample the data as much as possible to reduce artifacts.  My only fear of moving to the 100mp back is the issues discussed when shifting the lenses.  I decided even if I lose a little shift I want the improved live view for my tech system .. I'll see if I made a mistake in a few weeks.
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eronald

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Re: What happened to "CCD is better than CMOS"?!
« Reply #64 on: January 16, 2016, 08:02:00 pm »

Wayne -

 Congrats on your new purchase.  I look forward to hearing what you think of it.

 I think I should compliment Doug on the work he's doing to take the guesswork out of the purchasing decision.

 BTW, I don't know if this is relevant here, but I have an iPad Pro, and I've noticed that although the camera is poor the framing and compositional control one gets while holding this large screen is nothing short of incredible.

Edmund

to my recollection the thread title seems to focus on only a single point out of what was the original discussion which wasn't about CCD vs CMOS but was about  the supposed "medium format look".  CCD vs Cmos was only one element of that discussion which was theorized by some as one of the reason for the supposed "difference".

No need to resurrect it, just thought I'd mention it.  To me it's always been about resolution and the ability to oversample the data as much as possible to reduce artifacts.  My only fear of moving to the 100mp back is the issues discussed when shifting the lenses.  I decided even if I lose a little shift I want the improved live view for my tech system .. I'll see if I made a mistake in a few weeks.
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Christoph B.

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Re: What happened to "CCD is better than CMOS"?!
« Reply #65 on: January 16, 2016, 08:13:20 pm »

Christoph,

I'm dumb - what color is the tearoff sheet in the view camera really? Green or yellow?  Is it fluorescent?
Reflections can be hard because they can be polarised ...

Edmund

The sheet is definitely green and it's less saturated and more mint-green in the CMOS files, whereas it looks normally saturated in the CCD file. However the tripod in the left corner is very over-saturated.

Are you telling me that CMOS sensors react differently to polarised light than CCD sensors? Both the 50mpx and the 100mpx back seem to suffer from the same affliction of not being able to tell apart green polarised light from yellow polarised light...

I don't think you're dumb and I don't think you're blind - but I still don't understand why you don't see the difference. Maybe you don't have a calibrated screen? I don't know - in any case the difference is clearly visible. Just look at the frame of the window - it has a definite green color cast with the IQ380 but not with the IQ3100 or the IQ350. Same goes for that book in the lower right corner and I do think that the green colours are correct in the IQ380 photo.
And I don't think it's a WB issue, the reds and blues in the background look quite alright, if your changed anything it might end up getting worse.

Actually the longer I look at it the more IQ3100 ceases to impress me, the IQ350 photo looks much better and cleaner...and that one has the older CMOS sensor.. very strange! The 100mpx back has a lot of colour noise which almost looks like red banding - the 50mpx back is totally clean - although it was exposed with a higher ISO setting!

Something's off!
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Wayne Fox

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Re: What happened to "CCD is better than CMOS"?!
« Reply #66 on: January 16, 2016, 09:59:36 pm »


 BTW, I don't know if this is relevant here, but I have an iPad Pro, and I've noticed that although the camera is poor the framing and compositional control one gets while holding this large screen is nothing short of incredible.

I have the iPad Pro as well - one of the first things I'll test is that as well as the iPhone 6+ and Live View.
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eronald

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Re: What happened to "CCD is better than CMOS"?!
« Reply #67 on: January 16, 2016, 10:04:10 pm »

The sheet is definitely green and it's less saturated and more mint-green in the CMOS files, whereas it looks normally saturated in the CCD file. However the tripod in the left corner is very over-saturated.

Are you telling me that CMOS sensors react differently to polarised light than CCD sensors? Both the 50mpx and the 100mpx back seem to suffer from the same affliction of not being able to tell apart green polarised light from yellow polarised light...

I don't think you're dumb and I don't think you're blind - but I still don't understand why you don't see the difference. Maybe you don't have a calibrated screen? I don't know - in any case the difference is clearly visible. Just look at the frame of the window - it has a definite green color cast with the IQ380 but not with the IQ3100 or the IQ350. Same goes for that book in the lower right corner and I do think that the green colours are correct in the IQ380 photo.
And I don't think it's a WB issue, the reds and blues in the background look quite alright, if your changed anything it might end up getting worse.

Actually the longer I look at it the more IQ3100 ceases to impress me, the IQ350 photo looks much better and cleaner...and that one has the older CMOS sensor.. very strange! The 100mpx back has a lot of colour noise which almost looks like red banding - the 50mpx back is totally clean - although it was exposed with a higher ISO setting!

Something's off!

I'm telling you that
- if you have mixed light in an image ANY TWO cameras that do not have identical sensors and profiles will diverge in rendering.
- if you have random polarised light in an image, again every sensor can react differently. This cannot be avoided.
- if there is a peaky color eg that tear-off green again cameras will diverge. Fluorescence means that the material is absorbing UV or visible light energy and re-emitting it as a different frequency/color. The re-emission can be very spiky and its color in an image can change very easily.

Also, you are gray balancing on something that is almost black, a bad idea. Choose a nice large uniform gray area.

My feeling is that this scene with mixed light, reflectiions and fluorescence is a nightmare. It can be a nice test if you are evaluating a camera *for your own use*  but it is not informative for us pixel peepers. Also I am catching a hint that the new cam may be slightly more IR sensitive than the others. A filter might be a good idea. And if you say you prefer one camera to the other, why should I disagree, if you know what scenes you shoot and what results you expect. BTW,  if you want to take a quick stab at correcting the new cams image, just drop a gray level cursor on the cam frame *on the Tiff in Photoshop* The results look  cleaner. Profile, profile ...

Oh, and btw the light mix changed between exposure, one can see a well formed tree shadow on the brick wall in the middle image.
Edmund

« Last Edit: January 16, 2016, 10:16:43 pm by eronald »
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mjrichardson

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Re: What happened to "CCD is better than CMOS"?!
« Reply #68 on: January 17, 2016, 12:29:23 am »

Morning

I always find these discussions to be odd, there is so much variation in what people want from an image and from their equipment that I don't see how it is possible to say one is better because of this or one is better because of that, it can change image by image, never mind photographer by photographer.

I shoot daily with 2 cameras essentially the same but 1 is cmos and 1 is ccd, the S 006 and the S 007, using the same lenses. I know the strengths of each sensor for what I am shooting and use them accordingly. Those that say there is no difference obviously don't see a difference, nothing wrong with that but for me, as someone who shoots images rather than tests and comparisons, the differences are clear, in my opinion, putting it in it's most basic form, cmos is all about the shadows and ccd is all about the highlights.

If I am shooting a landscape that has the sun in the frame at base ISO then it's the ccd every time, the way it handles the highlights to blown out is just beautiful and I personally cannot get the cmos to handle the same way, but then this is entirely personal because I like shadows to be shadows and it is my preference to have that depth to an image, I often deepen shadows rather than raise them as seems to be the case with many people, each to their own.

I shoot a lot of corporate portraits, it's bread and butter work for me, about half the time I can set up lights and depending on the client brief, if they want bright shots then I am using the ccd for the same highlight handling on glasses, backgrounds etc. If they want natural light then I always pick up the cmos because I know inside offices and places I'm going to need ISO 400 or more to get what I want and this is where the cmos excels but at the cost of smoothness of highlight transitions, still better than I would get with the ccd.

If the cmos sensor handled exactly like the ccd sensor and the only difference was it could hold the same quality as the iso increases then that would be brilliant but for what I shoot it simply isn't the case, which is why I have both. We all like to shoot different things but stating that something is better because it happens to be better for you shooting your style just seems a bit wrong. How a sensor handles having shadows raised 100 and boosted 4 stops is of no interest to me personally because I have never shot that way and i wouldn't buy equipment based on how it handles that, I can only judge based on how I shoot and so my ideal camera will likely be different to many others.

It's all good, shoot what you like with what you like.

Mat
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ErikKaffehr

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Re: What happened to "CCD is better than CMOS"?!
« Reply #69 on: January 17, 2016, 01:38:19 am »

Hi,

That IR thing is interesting. I sort of think that IR sensivity and IR cutoff filters may play a role in rendition of vegetation and other chlorophyll rich stuff.

Best regards
Erik


I'm telling you that
- if you have mixed light in an image ANY TWO cameras that do not have identical sensors and profiles will diverge in rendering.
- if you have random polarised light in an image, again every sensor can react differently. This cannot be avoided.
- if there is a peaky color eg that tear-off green again cameras will diverge. Fluorescence means that the material is absorbing UV or visible light energy and re-emitting it as a different frequency/color. The re-emission can be very spiky and its color in an image can change very easily.

Also, you are gray balancing on something that is almost black, a bad idea. Choose a nice large uniform gray area.

My feeling is that this scene with mixed light, reflectiions and fluorescence is a nightmare. It can be a nice test if you are evaluating a camera *for your own use*  but it is not informative for us pixel peepers. Also I am catching a hint that the new cam may be slightly more IR sensitive than the others. A filter might be a good idea. And if you say you prefer one camera to the other, why should I disagree, if you know what scenes you shoot and what results you expect. BTW,  if you want to take a quick stab at correcting the new cams image, just drop a gray level cursor on the cam frame *on the Tiff in Photoshop* The results look  cleaner. Profile, profile ...

Oh, and btw the light mix changed between exposure, one can see a well formed tree shadow on the brick wall in the middle image.
Edmund
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tjv

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Re: What happened to "CCD is better than CMOS"?!
« Reply #70 on: January 17, 2016, 01:44:39 am »

While it's amazing that one can recover that much shadow information from a CMOS file, in my opinion the examples posted before look ridiculous. But I digress, because this thread has turned into a discussion that isn't so much about CCD vs. CMOS, but a discussion about personal taste. As much as I think the above mentioned samples look way over processed with poor colour and tonality, I can appreciate by other peoples measures they might see it differently. I guess difference of opinion makes the world go around.
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Christoph B.

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Re: What happened to "CCD is better than CMOS"?!
« Reply #71 on: January 17, 2016, 08:17:33 am »

I'm telling you that
- if you have mixed light in an image ANY TWO cameras that do not have identical sensors and profiles will diverge in rendering.
- if you have random polarised light in an image, again every sensor can react differently. This cannot be avoided.
- if there is a peaky color eg that tear-off green again cameras will diverge. Fluorescence means that the material is absorbing UV or visible light energy and re-emitting it as a different frequency/color. The re-emission can be very spiky and its color in an image can change very easily.

Also, you are gray balancing on something that is almost black, a bad idea. Choose a nice large uniform gray area.

My feeling is that this scene with mixed light, reflectiions and fluorescence is a nightmare. It can be a nice test if you are evaluating a camera *for your own use*  but it is not informative for us pixel peepers. Also I am catching a hint that the new cam may be slightly more IR sensitive than the others. A filter might be a good idea. And if you say you prefer one camera to the other, why should I disagree, if you know what scenes you shoot and what results you expect. BTW,  if you want to take a quick stab at correcting the new cams image, just drop a gray level cursor on the cam frame *on the Tiff in Photoshop* The results look  cleaner. Profile, profile ...

Oh, and btw the light mix changed between exposure, one can see a well formed tree shadow on the brick wall in the middle image.
Edmund

I think you missed my point;

What I said was that that it seems as if CMOS in general aren't very good at rendering greens - as an example I posted a link to a comparison between a Canon CMOS and a PhaseOne CCD back under the same conditions in a studio environment.

Random polarised light appear just about everywhere in nature. Does that mean I'd have to expect that the 3100 won't be able to deliver decent greens for landscape photography?
And which is it - polarised light or mixed light without polarisation? Not trying to pick a fight here but I truly think that if the CMOS sensors aren't that capable of capturing greens in a similar fashion as the CCDs - well then that means they are worse in that area.
Sure it can be only attributed to a profile error but that's a mighty coincidence if the old Canon CMOS and the new PhaseOne CMOS both have the same rendering problem and it's 'just' a profile issue. You'd think that with a 48.000$ gear that shouldn't happen as profiles can easily be changed and calibrated to deliver neutral colours.

I'm not grey balancing on anything, I didn't take those photos and I also doubt that both CMOS sensors just coincidentally produce weak greens or both coincidentally have a bad profile.

In the end time will tell - but if you remember the thread title is "What happened to "CCD is better than CMOS"?!" - and if there are serious colour issues with the CMOS sensors or if their colour rendering is noticeably different from the excellent CCD colour output - well then I'd say neither is better at the moment.


How a sensor handles having shadows raised 100 and boosted 4 stops is of no interest to me personally because I have never shot that way and i wouldn't buy equipment based on how it handles that, I can only judge based on how I shoot and so my ideal camera will likely be different to many others.


That's exactly what I'm thinking. As long as there are not neutral, unedited, well exposed shots under normal shooting conditions using the exact same white balance it's useless to compare those images.

I want to know how the colours look, how neutral it can be, whether there are any unexpected color shifts, which colours are rendered weak and strong - that's much more important to me than over-edited photos that have no real world relevance for shooting on a daily basis. Especially if those images are held up as an example of the superiority of CMOS technology.
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carloalberto

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Re: What happened to "CCD is better than CMOS"?!
« Reply #72 on: January 17, 2016, 10:48:24 am »

I have a CCD back, it delivers results better to my tastes than the CMOS cameras I own and I have no plans to buy a CMOS back in the immediate future.
So for me, the bird in hand is better than the one in the bush.

Does that answer your question?

Two in the bush....
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eronald

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Re: What happened to "CCD is better than CMOS"?!
« Reply #73 on: January 17, 2016, 10:56:01 am »

You are comparing systems under circumstances -mixed light- where they cannot match.
However you may have found a weakness in the Sony big chip CFA, for all I know, with that fluorescent tag.
IMHO the A7R2 has a sensor which is bad with greens, but the 50MP Cmos sensor seemed ok, in comparisons.
Someone else could reproduce the test, there is only one set of fluo colors AFAIK.

Originally, nobody here was expecting color issues from Cmos, rather texture loss and plastic skin, but I guess nobody was expecting Sony to become the only player. Sony has a culture of heavily numerically massaging and signal processing images, they are technologically agressive, maybe too agressive. The western players - Dalsa, Kodak, Jenoptik- were more science driven.  Which is why they published datasheets with the spectral specs.

If you just put specs on a spreadsheet page, Getting good ISO and numerical DR will always win over IR sensitivity and hard to quantify metameric effects like those one can see in your example shots; so,companies will tend to cut corners on color. Leica put the M8 on the market even though *they* knew it had IR issues. It got them cash flow and the reviewers and then users just shut up. That is why at some point one has to rely on the brand's reputation, the dealer, or do one's own testing.

Frankly, The sony 50c seems a good chip, and I would be surprised and disappointed if the 100 is not as good.
On the other hand we dont know what the Phase cover glass, signal processing and profile do. Phase and Sony may have thought the big S/N and in-house profile editing know-how would allow them to numerically clean up any residual color discrimination or IR contamination issues in practical situations, at least at low ISO. It will be interesting to see the Hassy version.

Edmund.

I think you missed my point;

What I said was that that it seems as if CMOS in general aren't very good at rendering greens - as an example I posted a link to a comparison between a Canon CMOS and a PhaseOne CCD back under the same conditions in a studio environment.

Random polarised light appear just about everywhere in nature. Does that mean I'd have to expect that the 3100 won't be able to deliver decent greens for landscape photography?
And which is it - polarised light or mixed light without polarisation? Not trying to pick a fight here but I truly think that if the CMOS sensors aren't that capable of capturing greens in a similar fashion as the CCDs - well then that means they are worse in that area.
Sure it can be only attributed to a profile error but that's a mighty coincidence if the old Canon CMOS and the new PhaseOne CMOS both have the same rendering problem and it's 'just' a profile issue. You'd think that with a 48.000$ gear that shouldn't happen as profiles can easily be changed and calibrated to deliver neutral colours.

I'm not grey balancing on anything, I didn't take those photos and I also doubt that both CMOS sensors just coincidentally produce weak greens or both coincidentally have a bad profile.

In the end time will tell - but if you remember the thread title is "What happened to "CCD is better than CMOS"?!" - and if there are serious colour issues with the CMOS sensors or if their colour rendering is noticeably different from the excellent CCD colour output - well then I'd say neither is better at the moment.


That's exactly what I'm thinking. As long as there are not neutral, unedited, well exposed shots under normal shooting conditions using the exact same white balance it's useless to compare those images.

I want to know how the colours look, how neutral it can be, whether there are any unexpected color shifts, which colours are rendered weak and strong - that's much more important to me than over-edited photos that have no real world relevance for shooting on a daily basis. Especially if those images are held up as an example of the superiority of CMOS technology.
« Last Edit: January 17, 2016, 11:29:52 am by eronald »
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ErikKaffehr

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A general comment on the thread...
« Reply #74 on: January 17, 2016, 11:34:35 am »

Hi,

It seems that you gentlemen forgot about the simple fact that both CCD and CMOS are essentially devices collection electrons in capacitors and measuring the related voltage. The main difference is that CMOS measures that voltage in place, while CCD uses a bucket shift 'mechanism' to pop those electron charges into an external preamplifier.

Both devices are absolutely monochrome. Any colour is added by the CFA (Colour Filter Array) in front of the sensor and interpreted by the raw converter. Some guys state the Sony applies tricks to the electrons, but if that is the case, I am pretty sure that any such processing is selectable, so if say Phase One doesn't have spatial filtering at high ISOs they can disable that feature.

It is very clear that at least some A7-series cameras apply median filtering at high ISO-s, that can be clearly detected by FFT analysis of dark exposures. But, Sony employs this at very high ISO only and I am pretty sure that Phase One can choose to use it or not in their implementation.

So, any observed differences in colour rendition are due to either CFA design or post processing.

Now, I am fully aware that spectral sensivity of sensors varies with design and also that there are differences in IR response. But I am pretty sure that those differences can be handled by proper CFA design and IR filtering combined with properly designed colour profiles.

Best regards
Erik

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Christoph B.

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Re: What happened to "CCD is better than CMOS"?!
« Reply #75 on: January 17, 2016, 02:02:12 pm »

Hi,

It seems that you gentlemen forgot about the simple fact that both CCD and CMOS are essentially devices collection electrons in capacitors and measuring the related voltage. The main difference is that CMOS measures that voltage in place, while CCD uses a bucket shift 'mechanism' to pop those electron charges into an external preamplifier.

Both devices are absolutely monochrome. Any colour is added by the CFA (Colour Filter Array) in front of the sensor and interpreted by the raw converter. Some guys state the Sony applies tricks to the electrons, but if that is the case, I am pretty sure that any such processing is selectable, so if say Phase One doesn't have spatial filtering at high ISOs they can disable that feature.


Just because both don't distinguish color per se doesn't mean that both are equally capable of recording the same amount and/or quality of information.

I've spent the day doing a bit of research - if someone spots an error please tell me, otherwise it sounds pretty reasonable;

CMOS sensors are (without a filter) indeed very sensitive to red and near-infrared wavelengths (>650nm) and CCD sensors are very sensitive to the visible spectrum (550nm). The conversion efficiency of CMOS sensors at 550 nm is generally rather low, it peaks at 30%-40% while on CCD sensors it's more like 70% or above - that may be the reason why CMOS sensors seem to struggle with greens (495570 nm) and often translate them as yellows (570590 nm)as they are more sensitive to that side of the spectrum.
That also explains why many people see a reddish or brownish tone in CMOS photos even with the correct WB and profile.

Perhaps a stronger IR-filter would be the solution but right now I'm sure they're not getting the greens right on the 100mp sensor and the 50mp seems to suffer from the same issue as well.
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eronald

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Re: What happened to "CCD is better than CMOS"?!
« Reply #76 on: January 17, 2016, 05:05:52 pm »


Just because both don't distinguish color per se doesn't mean that both are equally capable of recording the same amount and/or quality of information.

I've spent the day doing a bit of research - if someone spots an error please tell me, otherwise it sounds pretty reasonable;

CMOS sensors are (without a filter) indeed very sensitive to red and near-infrared wavelengths (>650nm) and CCD sensors are very sensitive to the visible spectrum (550nm). The conversion efficiency of CMOS sensors at 550 nm is generally rather low, it peaks at 30%-40% while on CCD sensors it's more like 70% or above - that may be the reason why CMOS sensors seem to struggle with greens (495570 nm) and often translate them as yellows (570590 nm)as they are more sensitive to that side of the spectrum.
That also explains why many people see a reddish or brownish tone in CMOS photos even with the correct WB and profile.

Perhaps a stronger IR-filter would be the solution but right now I'm sure they're not getting the greens right on the 100mp sensor and the 50mp seems to suffer from the same issue as well.

Christoph,

 If you have experience as a photographer, I think you are fully entitled to make buying decisions based on the personal impressions you have of the camera's rendering. The tech is irrelevant to the user - I don't think most photographers were experts on film chemistry and dyes.

Edmund
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bjanes

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Re: What happened to "CCD is better than CMOS"?!
« Reply #77 on: January 17, 2016, 06:05:58 pm »


Just because both don't distinguish color per se doesn't mean that both are equally capable of recording the same amount and/or quality of information.

I've spent the day doing a bit of research - if someone spots an error please tell me, otherwise it sounds pretty reasonable;

CMOS sensors are (without a filter) indeed very sensitive to red and near-infrared wavelengths (>650nm) and CCD sensors are very sensitive to the visible spectrum (550nm). The conversion efficiency of CMOS sensors at 550 nm is generally rather low, it peaks at 30%-40% while on CCD sensors it's more like 70% or above - that may be the reason why CMOS sensors seem to struggle with greens (495570 nm) and often translate them as yellows (570590 nm)as they are more sensitive to that side of the spectrum.
That also explains why many people see a reddish or brownish tone in CMOS photos even with the correct WB and profile.

Perhaps a stronger IR-filter would be the solution but right now I'm sure they're not getting the greens right on the 100mp sensor and the 50mp seems to suffer from the same issue as well.

Perhaps you could supply us with some of your references to back up your assertions. One caveat in comparing CCD vs CMOS designs is the date of the comparison. CMOS designs have been dramatically improved recently, and the older literature comparing the two types of sensors may not be current.

For example, here is an article from 2011 showing how CMOS has gained with respect to CCD. Here is another from 2009. This is now 2016. Note that these articles are from the scientific imaging community where CCDs have long predominated over CMOS.

Bill
« Last Edit: January 17, 2016, 06:15:06 pm by bjanes »
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bjanes

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Re: A general comment on the thread...
« Reply #78 on: January 17, 2016, 06:33:26 pm »

It seems that you gentlemen forgot about the simple fact that both CCD and CMOS are essentially devices collection electrons in capacitors and measuring the related voltage. The main difference is that CMOS measures that voltage in place, while CCD uses a bucket shift 'mechanism' to pop those electron charges into an external preamplifier.

Both devices are absolutely monochrome. Any colour is added by the CFA (Colour Filter Array) in front of the sensor and interpreted by the raw converter. Some guys state the Sony applies tricks to the electrons, but if that is the case, I am pretty sure that any such processing is selectable, so if say Phase One doesn't have spatial filtering at high ISOs they can disable that feature.

It is very clear that at least some A7-series cameras apply median filtering at high ISO-s, that can be clearly detected by FFT analysis of dark exposures. But, Sony employs this at very high ISO only and I am pretty sure that Phase One can choose to use it or not in their implementation.

So, any observed differences in colour rendition are due to either CFA design or post processing.

Now, I am fully aware that spectral sensivity of sensors varies with design and also that there are differences in IR response. But I am pretty sure that those differences can be handled by proper CFA design and IR filtering combined with properly designed colour profiles.

Eric,

Here are some comments on this topic by an expert, Eric Fossum, who invented CMOS. The whole thread is worth reading. Your opinions are supported here.

Bill
« Last Edit: January 17, 2016, 06:37:53 pm by bjanes »
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eronald

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Re: A general comment on the thread...
« Reply #79 on: January 17, 2016, 07:24:03 pm »

Eric,

Here are some comments on this topic by an expert, Eric Fossum, who invented CMOS. The whole thread is worth reading. Your opinions are supported here.

Bill

Bill,

 The question here isn't whether the abilities of CCD are different from CMOS, it is whether the actually produced MF cameras are different.

 At the moment there is one manufacturer - SONY - of such sensors. One instance isn't guaranteed perfect just because Eric Fossum says so. And the inventor of CMOS sensors would be expected to thing well of CMOS optical sensors, every inventor loves his child most.

Edmund
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