Luminous Landscape Forum
Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: Paul2660 on February 24, 2015, 07:30:20 pm
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There has been so much talk recently on this forum and others about CMOS and CCD and the difference in color and dynamic range between the two technologies. I wanted to post this crop and I hope it shows up large enough for you folks to see. This crop was taken right from C1 and shows the massive difference that a shutter speed of 1/4 of second and 1 second make in shadows. Both of these crops are from the far right of of 15mm shift from a 40mm Rodie at F11 on a IQ260. The areas in the shot that received normal light look about the same, you can see this in the dogwood leaves (pale red) and some of the green leaves above the dogwood. However look at the shadows right above the dogwood. Here you can see some grasses and foliage typical of a Ozark mountain, moss, twigs etc. It's just not really there on the 1/4 shot, yes, you can make it out, but it's vague and not well formed. Looking at the 1 second shot, you can make out individual grass blades and look well back into the shadows. This is using Capture One, 8 which is by far the best version I have used.
I see this over and over in my work. I love the color that such chips are capable of creating, but when you lose all the available details in the shadows it really makes for a tasking shot. You won't get them back, as the CCD did not have enough light to figure out what these structures were so it's just muddy. The 1 second shot has plenty of details (all I need to do is add a bit of focus magic if I really want to pull them out). You can also see the same issue in some of the smaller green leaves. On the 1/4 second shot you can see the leaves but they show noise and no details.
This was taken in mixed light, which is most typical of my working environment.
No having a CMOS back to compare, I don't know what it would done color wise, but I can assure you that it would have given much more detail than even my 1 second exposure.
Now consider the shooting situation I was in. This is 3 part shift looking down a row of Sweet Gum's that line a river bluff and each year there is a brief period where they are all yellow and red. This is a classic mixed light shot as the distant bluff is brightly lit up, but the foreground is in shade. So you have to bracket anyway. If there was wind blowing, then I would have needed iso 200 (a real stretch on a IQ260) or iso 400 (not worth the trouble in low light) to stop the motion of the leaves. As it was this afternoon there was just a light intermittent breeze and I was able to get the shot I wanted.
This image is a bit soft and I contribute that to fact that it's the far edge of a shift 15mm and at 1 second I may had just a tad of motion blurr, but I don't see it as enough to effect the image.
The Phase One backs are amazing in what they can do, if the conditions will allow it.
Paul
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Hi Paul,
Could you "lift" the shadows in the 1/4s exposure? From the sample it is hard to see if the lack of tonal separation in the darks is due to darkness and possibly a toe characteristics on the tone curve or by the lack of tonal separation in the raw data.
Another point that Anders Torger made on a thread at GetDPI, is that there may be to few photons captured. The way it seems, modern CMOS is very good at keeping down readout noise, but they cannot do anything about low photons counts.
To examplify:
Let's assume that a group of pixels collect 64 photons in average. In this case photon noise would be 8 photons, so we would have a quite decent signal/noise ration of 64/8 = 8.
Now, a typical CCD may have 12 electron charges of readout noise. Each sample photon corresponds one electron (by and large). Noise adds in quadrature, so we would have a total noise of sqrt( 12 * 12 + 8 * 8 ) = 14.4 electron charges. So SNR would be 64/14.4 = 4.4, not so impressive.
With a Nikon D810 readout noise may be more like 2 electrons, so SNR may be like: 64 / sqrt( 2*2 + 8*8 ) = 7.76 that is almost pure shot (photon) noise. So it would give cleaner shadows. But, the photon count may be not enough to offer good separation in colour.
Best regards
Erik
There has been so much talk recently on this forum and others about CMOS and CCD and the difference in color and dynamic range between the two technologies. I wanted to post this crop and I hope it shows up large enough for you folks to see. This crop was taken right from C1 and shows the massive difference that a shutter speed of 1/4 of second and 1 second make in shadows. Both of these crops are from the far right of of 15mm shift from a 40mm Rodie at F11 on a IQ260. The areas in the shot that received normal light look about the same, you can see this in the dogwood leaves (pale red) and some of the green leaves above the dogwood. However look at the shadows right above the dogwood. Here you can see some grasses and foliage typical of a Ozark mountain, moss, twigs etc. It's just not really there on the 1/4 shot, yes, you can make it out, but it's vague and not well formed. Looking at the 1 second shot, you can make out individual grass blades and look well back into the shadows. This is using Capture One, 8 which is by far the best version I have used.
I see this over and over in my work. I love the color that such chips are capable of creating, but when you lose all the available details in the shadows it really makes for a tasking shot. You won't get them back, as the CCD did not have enough light to figure out what these structures were so it's just muddy. The 1 second shot has plenty of details (all I need to do is add a bit of focus magic if I really want to pull them out). You can also see the same issue in some of the smaller green leaves. On the 1/4 second shot you can see the leaves but they show noise and no details.
This was taken in mixed light, which is most typical of my working environment.
No having a CMOS back to compare, I don't know what it would done color wise, but I can assure you that it would have given much more detail than even my 1 second exposure.
Now consider the shooting situation I was in. This is 3 part shift looking down a row of Sweet Gum's that line a river bluff and each year there is a brief period where they are all yellow and red. This is a classic mixed light shot as the distant bluff is brightly lit up, but the foreground is in shade. So you have to bracket anyway. If there was wind blowing, then I would have needed iso 200 (a real stretch on a IQ260) or iso 400 (not worth the trouble in low light) to stop the motion of the leaves. As it was this afternoon there was just a light intermittent breeze and I was able to get the shot I wanted.
This image is a bit soft and I contribute that to fact that it's the far edge of a shift 15mm and at 1 second I may had just a tad of motion blurr, but I don't see it as enough to effect the image.
The Phase One backs are amazing in what they can do, if the conditions will allow it.
Paul
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Hi Paul,
Could you "lift" the shadows in the 1/4s exposure? From the sample it is hard to see if the lack of tonal separation in the darks is due to darkness and possibly a toe characteristics on the tone curve or by the lack of tonal separation in the raw data.
Another point that Anders Torger made on a thread at GetDPI, is that there may be to few photons captured. The way it seems, modern CMOS is very good at keeping down readout noise, but they cannot do anything about low photons counts.
To examplify:
Let's assume that a group of pixels collect 64 photons in average. In this case photon noise would be 8 photons, so we would have a quite decent signal/noise ration of 64/8 = 8.
Now, a typical CCD may have 12 electron charges of readout noise. Each sample photon corresponds one electron (by and large). Noise adds in quadrature, so we would have a total noise of sqrt( 12 * 12 + 8 * 8) = 14.4 electron charges. So SNR would be 64/14.4 = 4.4, not so impressive.
With a Nikon D810 readout noise may be more like 2 electrons, so SNR may be like: sqrt( 2*2 + 8*8) = 7.76 that is almost pure shot (photon) noise. So it would give cleaner shadows. But, the photon count may be not enough to offer good separation in colour.
Best regards
Erik
Hi Eric,
They were lifted, I forgot to mention this. I pulled shadows from both the main tool set, and in an adjustment layer. I tried to get the info bar to show but the image was too large.
This is why I bracket pretty much every shot, when I have extreme shadows, as I know I will get a shutter speed that will get there. However with a tech camera this is tedious and can bring blur into play just due to moving too fast between setting/cocking and firing the shutter, which I have been known to do :) I forgot to mention that these are both iso 50 image, i.e the supposed base of the IQ260, but that may be a false as a lot of evidence now shows it's really iso100 not 50.
Paul
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Another point that Anders Torger made on a thread at GetDPI, is that there may be to few photons captured. The way it seems, modern CMOS is very good at keeping down readout noise, but they cannot do anything about low photons counts.
With a Nikon D810 readout noise may be more like 2 electrons, so SNR may be like: sqrt( 2*2 + 8*8) = 7.76 that is almost pure shot (photon) noise. So it would give cleaner shadows. But, the photon count may be not enough to offer good separation in colour.
Best regards
Erik
Again I need to see hard evidence for this, not just speculations. I post again here:
It would be good to know whether your claimed lack of color / dynamism / realism is true from pushed shadows. I don't see such difference imo. Below shows the identical color / look / saturation etc from two bracketed exposures 2ev apart. (link to download raw (https://www.dropbox.com/sh/479ue4gi3t3e1dq/AAAugZpRyvz6GJ9AX87WMFBQa?dl=0))
(https://1xzpta.dm2302.livefilestore.com/y2p3FcLTNXF0iGwXtEuy7nuMT4zNkSYbFRelZGRThHKqWfWYQUcFEngKb17S2CxQMHVOpyuFn_H1F0sBbkRttnEUucaeVrkZmlKC86VmrYG3kdnD6oYvGOiPcs8N8TWft2Y5Xst6XEs0kHwLSZwJDKU5w/71.JPG?psid=1)
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With a Nikon D810 readout noise may be more like 2 electrons, so SNR may be like: sqrt( 2*2 + 8*8) = 7.76 ...
Eric, you need to check "Don't use smileys" when you post, to avoid misinterpretation of "8)" as "Cool"!
(Also, sqrt( 2*2 + 8*8) = 8.25.)
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Thanks,
I mixed up noise and NSR, now fixed!
Best regards
Erik
Eric, you need to check "Don't use smileys" when you post, to avoid misinterpretation of "8)" as "Cool"!
(Also, sqrt( 2*2 + 8*8) = 8.25.)
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Hi,
I have looked at your images a bit. Now, these are from the IQ-250, which doesn't have the CCD-sensors MFD used to have.
One impression I may have that Capture One is overdoing noise reduction.
Below are same samples from:
- C1 using no NR and LR using no NR
- C1 using default NR and LR using no NR
- C1 using no NR and AccuRaw using default NR
Best regards
Erik
Again I need to see hard evidence for this, not just speculations. I post again here:
It would be good to know whether your claimed lack of color / dynamism / realism is true from pushed shadows. I don't see such difference imo. Below shows the identical color / look / saturation etc from two bracketed exposures 2ev apart. (link to download raw (https://www.dropbox.com/sh/479ue4gi3t3e1dq/AAAugZpRyvz6GJ9AX87WMFBQa?dl=0))
(https://1xzpta.dm2302.livefilestore.com/y2p3FcLTNXF0iGwXtEuy7nuMT4zNkSYbFRelZGRThHKqWfWYQUcFEngKb17S2CxQMHVOpyuFn_H1F0sBbkRttnEUucaeVrkZmlKC86VmrYG3kdnD6oYvGOiPcs8N8TWft2Y5Xst6XEs0kHwLSZwJDKU5w/71.JPG?psid=1)
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I think most raw converters overdo noise reduction. I think it's because they want to make a clean pixel peep impression rather than thinking about how global color look in a print. Some grain is no problem for a print, but dead color is.
Concerning my observation that there might be not enough photons to give good colors in pushed shadows it's indeed a speculation, trying to explain what I see in many shots. I haven't yet looked at the above shots, but I guess 2 pushed stops may not be enough to show a significant effect, I'm thinking more like 4 stops.
What I often see in backlit landscape scenes with pushed shadows is that there's often a brown(ish)-centered palette in the pushed areas, color does not look as good in the well-exposed areas. I have not investigated in detail why this is, but have speculated that it's too few photons captured to make good color.
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Sila mygg och svälja elefanter...
/Erik
I think most raw converters overdo noise reduction. I think it's because they want to make a clean pixel peep impression rather than thinking about how global color look in a print. Some grain is no problem for a print, but dead color is.
Concerning my observation that there might be not enough photons to give good colors in pushed shadows it's indeed a speculation, trying to explain what I see in many shots. I haven't yet looked at the above shots, but I guess 2 pushed stops may not be enough to show a significant effect, I'm thinking more like 4 stops.
What I often see in backlit landscape scenes with pushed shadows is that there's often a brown(ish)-centered palette in the pushed areas, color does not look as good in the well-exposed areas. I have not investigated in detail why this is, but have speculated that it's too few photons captured to make good color.
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Here's a demo of what I see. Both files are processed in RawTherapee and have exactly the same processing parameters, except that the darker (the first) has been pushed 2 more stops. In theory they should look identical.
Watch both images side by side or layer them on top of eachother (it can be hard to see differences when above and below like they become here, unfortunately) and see that the colors are not the same in the shadows, the benches are a good thing to look at, but you can see differences in brighter colors too. The underexposed file has taken on a greenish cast (I've noted that it varies if sensors take on a greenish or brownish cast when underexposed, this sensor seems to be of the green type, while D800 is brown if I remember correctly). I'm sure color separation is noticeably worse too, but as it's mostly only brown wood there we don't see it in this picture.
Note: in this case I've used Capture One's IQ250 tungsten icc profile, which might have hue twists which could affect the result. It would have been better if I've just used plain matrix color (guaranteed linear without hue twists), however I just did a comparison with matrix color and the difference in look is the same, so if there are any hue twists in the IQ250 icc it's negligible for this comparison.
This reduced color fidelity I think is a problem, and therefore I don't think it's a good idea to underexpose and push hard, even if the sensor has low read noise, and therefore I think that the advantage of Sony Exmor clean shadows is exaggerated when it comes to high fidelity photography, it doesn't free you from making good exposures if you want good color.
I haven't really investigated this phenomenon in detail, it would be interesting to do. I suspect that if you are concerned about color fidelity the extra 1-2 stop you gain in noise with the Sony sensor is not very usable as color fidelity is poor anyway. (If you're into long exposure then there's a lot to gain though, the examples of IQ260 I've seen has been quite disappointing, it depends so heavily on noise reduction that color fidelity and detail must suffer a lot, my guess is that the P45+ actually produces better results for long exposure, both in terms of detail and color, and of course the IQ250 is best.)
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Here's a demo of what I see. Both files are processed in RawTherapee and have exactly the same processing parameters, except that the darker (the first) has been pushed 2 more stops. In theory they should look identical.
Watch both images side by side or layer them on top of eachother (it can be hard to see differences when above and below like they become here, unfortunately) and see that the colors are not the same in the shadows, the benches are a good thing to look at, but you can see differences in brighter colors too. The underexposed file has taken on a greenish cast (I've noted that it varies if sensors take on a greenish or brownish cast when underexposed, this sensor seems to be of the green type, while D800 is brown if I remember correctly). I'm sure color separation is noticeably worse too, but as it's mostly only brown wood there we don't see it in this picture.
Note: in this case I've used Capture One's IQ250 tungsten icc profile, which might have hue twists which could affect the result. It would have been better if I've just used plain matrix color (guaranteed linear without hue twists), however I just did a comparison with matrix color and the difference in look is the same, so if there are any hue twists in the IQ250 icc it's negligible for this comparison.
This reduced color fidelity I think is a problem, and therefore I don't think it's a good idea to underexpose and push hard, even if the sensor has low read noise, and therefore I think that the advantage of Sony Exmor clean shadows is exaggerated when it comes to high fidelity photography, it doesn't free you from making good exposures if you want good color.
I haven't really investigated this phenomenon in detail, it would be interesting to do. I suspect that if you are concerned about color fidelity the extra 1-2 stop you gain in noise with the Sony sensor is not very usable as color fidelity is poor anyway. (If you're into long exposure then there's a lot to gain though, the examples of IQ260 I've seen has been quite disappointing, it depends so heavily on noise reduction that color fidelity and detail must suffer a lot, my guess is that the P45+ actually produces better results for long exposure, both in terms of detail and color, and of course the IQ250 is best.)
What you see here is just color cast of shadow noise. The shadow noise of a Sony Exmor can sometimes have a green cast and sometimes have a magenta cast. It has nothing to do with color fidelity. A while ago I did an article about how to achieve great dynamic range with temporal noise reduction. The method was to use a Nikon D800 to continuously shoot 60 severely underexposed images, then push them in ACR and stack them in Photoshop to reduce shadow noise. It's the same way as how Red Epic Dragon scores top 1 dynamic range at dxomark.com.
(https://1xzpta.dm2302.livefilestore.com/y2pvmSM4_wAr7xxDJLGUUycHXO12r-TMVzD8CcMPlRLjHS0DZAzMfoTMW9bm1foQhswurOkQuJkS6JRFxvobrjhRTE89Vpsa4GN74IrQNTy2QUbpbzlOKEE5-LwGJCHteRFhW-EI9Sy9fVSIl3T2mFE3Q/rd.JPG?psid=1)
(https://1xzpta.dm2302.livefilestore.com/y2pYbO1aV9kDvowi43bN4KuSU7fo9aqIF8ii-OPKl9N1--qg-51y4peWQoWj3_-dCFywqWg24IiHyvkMWFvCVYsozLlT1VQZ-124nFGkHoc_MIyuJNyLtENifrFIIV4B358vK33ezqU-0_JP9SxZHau1w/files.JPG?psid=1)
(https://1xzpta.dm2302.livefilestore.com/y2pDAojctqZpMQw4LpixHKM-HVsBQ1Lwzrd2XLhKfroT--Tfb-yQLcH_MKsJVaGyPVf3mandS-iyUEHS_tG7rdgYJoAse60WGcCsGmj7X06MtcipEFFQpPU2kziMx6qekeXemxhrCKPNZ8G20MctfRsOw/acr_1_en.jpg?psid=1)
(https://1xzpta.dm2302.livefilestore.com/y2pnmo7Iiy5dL1hZAdOBRTEY5jCSYyKRG5Vp_7IemYIB84IXOC-jSVLRWXNafQGWgdp3kQPZHfZlhcw_JBZUxWcax42fUabyP8mV0C-3zR4jYXgCNZQWNK5ABWj_OWVEQPNWRaxU5RsRBtiJWTJwnMrXA/acr_2_en.jpg?psid=1)
(https://1xzpta.dm2302.livefilestore.com/y2pdnkNzdqclxUbN7tamJF6ZlLyPhKMrXd4lpRfW0E8TjSh4STBPWn3C80t-UJBqd6Gh0AogOmQaNYkbwZiiFiyddBFhaUx8do4NvmljAjvzQYWe9eRJErlgqowQstyQKtcriMlBtd9Wmk04GuxIxsH1A/stats.jpg?psid=1)
(https://1xzpta.dm2302.livefilestore.com/y2p8hy6ziG-P_5tWkTzvvDKSBnrgPWSUYiC0ZZNNAFM0Xsh7z23JGSH8Um12zMX54BjWsUejqu-qQOSHRpVE6q81kXi2KYoaOWrkxEWIS26KZBUOdSatb5Ph8ChS_vwwbGJ0vh3_crKvpwOO4bxfd3XiQ/stats2.JPG?psid=1)
(https://1xzpta.dm2302.livefilestore.com/y2pBiNM1FLq9WjxRAM99FmEetVbxx8P5PqNqiWSkiYZnGbYhNevwWswImmNCJISC1iSUvXqw4Q4fwQMMI7Wmh6O8BGKfXN14SC1sJdgOMglgYmMHA0Vezs6XyB0VVTE75nIDkNH2-g-FHkFJ-CK4P5grg/_DSC0452_stacked_shadow_details_en.jpg?psid=1)
(https://1xzpta.dm2302.livefilestore.com/y2pd8164hJ_E4RF4JMqfaav-X6pIeFt63bdS3wZTiwrDKa8l72CCca3716go61WTX6zI1SKgMdmomCK_a5MSf2cpcQIUm82lQqDKeRZIIQV7ctlYB_y-MVjvvtGiYyw8Jw7Ck9qJeOYKFushdPnL1oI1w/_DSC0452_stacked-v2.jpg?psid=1)
(https://1xzpta.dm2302.livefilestore.com/y2p5BdRqvISwf1oVWOT4OWbD5ON-9tvmemWn8ouG-4PtMtDWHXa1JUqP0qGhGSDKotZ5LKapzPgWHNDQhItt1x-s_QSiZYJ82FN8S0dkKxdTOkhPFUXpy3vrxc8EQ5qxVgW5XnU28jGekkNhpyqbicr_Q/shadow_cast.jpg?psid=1)
If you pay attention to the shadow noise you would see that even throughout the same session of continuous shots (i.e. same temperature, humidity, light etc) you can't expect the color of shadow noise to be neutral for each frame. However the good part is that if you shoot many enough, then the color cast of noise of each frame eventually cancels each other and you get a neutral one (consider that the number of green cast frames are equal to the number of magenta cast frames).
Actually looking back to other shadow push examples, you would see that the IQ250 had magenta shadow noise while the D800E had green shadow noise. If you shoot more frames under the same condition, you could get the opposite results.
(https://1xzpta.dm2302.livefilestore.com/y2pZ9QgcF9OlROFOv0o_bCyMvuefIwBdVR7rEJ3podx79s-ytpeg6BargoxtHWr3IP7nlshfMli1OiczJz6gxYhSanOrbW6Fjdb_enuGa-Ozub0lIdbJeX3zvG09obXw7kcvGbgcI9h5k4DfyZLpJ8NHA/DR1_IQ250_IQ260_D800E.JPG?psid=1)
I would say that if you stay away from pushing the shadow too far producing shadow noise, then the extra 3 (yes, three) stops you gain in noise with the Sony sensor is very usable.
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There has been so much talk recently on this forum and others about CMOS and CCD and the difference in color and dynamic range between the two technologies. I wanted to post this crop and I hope it shows up large enough for you folks to see. This crop was taken right from C1 and shows the massive difference that a shutter speed of 1/4 of second and 1 second make in shadows. Both of these crops are from the far right of of 15mm shift from a 40mm Rodie at F11 on a IQ260. The areas in the shot that received normal light look about the same, you can see this in the dogwood leaves (pale red) and some of the green leaves above the dogwood. However look at the shadows right above the dogwood. Here you can see some grasses and foliage typical of a Ozark mountain, moss, twigs etc. It's just not really there on the 1/4 shot, yes, you can make it out, but it's vague and not well formed. Looking at the 1 second shot, you can make out individual grass blades and look well back into the shadows. This is using Capture One, 8 which is by far the best version I have used.
I see this over and over in my work. I love the color that such chips are capable of creating, but when you lose all the available details in the shadows it really makes for a tasking shot. You won't get them back, as the CCD did not have enough light to figure out what these structures were so it's just muddy. The 1 second shot has plenty of details (all I need to do is add a bit of focus magic if I really want to pull them out). You can also see the same issue in some of the smaller green leaves. On the 1/4 second shot you can see the leaves but they show noise and no details.
This was taken in mixed light, which is most typical of my working environment.
No having a CMOS back to compare, I don't know what it would done color wise, but I can assure you that it would have given much more detail than even my 1 second exposure.
Now consider the shooting situation I was in. This is 3 part shift looking down a row of Sweet Gum's that line a river bluff and each year there is a brief period where they are all yellow and red. This is a classic mixed light shot as the distant bluff is brightly lit up, but the foreground is in shade. So you have to bracket anyway. If there was wind blowing, then I would have needed iso 200 (a real stretch on a IQ260) or iso 400 (not worth the trouble in low light) to stop the motion of the leaves. As it was this afternoon there was just a light intermittent breeze and I was able to get the shot I wanted.
This image is a bit soft and I contribute that to fact that it's the far edge of a shift 15mm and at 1 second I may had just a tad of motion blurr, but I don't see it as enough to effect the image.
The Phase One backs are amazing in what they can do, if the conditions will allow it.
Paul
Try using the Roddie 40 at f8 instead of f11. I find that sharpness is reduced significantly at f11 vs f5.6~f8. Dof is not that much different in typical landscape situations.
Also, if the shadow areas are in the outer edges of the image circle then it's a double whammy since you are not only bringing up the shadows in post but correcting for the vignetting (and color cast) of the lens as well (which is not bad on the 40mm roddie but still there is some).
But, this extreme shadow recovery, specially in longer exposures (bad light) and of course higher iso / long exposure performance are the only weaknesses of the latest CCD medium format backs. They are superb in most situations.
So, if your typical shooting involves needing high iso, long exposures and/or EXTREME shadow recovery then the Sony CMOSs are the right choice for you.
Right tool for the job.
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What you see here is just color cast of shadow noise.
Let us assume it's indeed a shot noise issue, then stacking will solve it as it's a way of gathering more photons.
Varying color of the cast from time to time sounds interesting indeed, I would guess it may be due to narrow band light sources, but if it indeeds varies under the same conditions over time I do wonder what the reason is, and then it's a larger color fidelity issue as you can't simply apply a static correction, you would need to hand-tune it from time to time, or just ignore it as most would do.
That shadow color cast has nothing to do with color fidelity I disagree with, there's a cast to start with. I guess you mean that if you just correct the cast there's no issue with color separation (and hue/saturation), and well that might be true but I seriously doubt that and would like to test sometime, shooting a color checker with various degrees of underexposure would be a good lab condition test.
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Note: in this case I've used Capture One's IQ250 tungsten icc profile, which might have hue twists which could affect the result. It would have been better if I've just used plain matrix color (guaranteed linear without hue twists), however I just did a comparison with matrix color and the difference in look is the same, so if there are any hue twists in the IQ250 icc it's negligible for this comparison.
Looked a bit closer, and yes there are significant hue twists in the profile, the different color on the quite bright organ in the center is due to the profile. The shadow color cast is still there with linear color conversion though.
I haven't really checked recently how C1 applies their profiles, do they do it before or after exposure correction? If they do it before (like RT does) the advantage is that you can make a profile that corrects for nonlinearities in color response (this is what you would want to do in reproduction), but the disadvantage is that a profile with hue twists will yield different color depending on exposure correction. Adobe's DCP has two sets of color correction tables, one that is applied before exposure correction (the purpose is to correct color) and the other is after exposure correction/tonemapping etc (the purpose is to apply a subjective look). That's an advantage of DCP over ICC... with ICC you need to choose if to apply it before or after...
posting a linear conversion soon...
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That shadow color cast has nothing to do with color fidelity I disagree with, there's a cast to start with. I guess you mean that if you just correct the cast there's no issue with color separation (and hue/saturation), and well that might be true but I seriously doubt that and would like to test sometime, shooting a color checker with various degrees of underexposure would be a good lab condition test.
No. I mean if you don't push too hard to have visible shadow noise then you don't have color cast. Compared against the CCD sensors and the current Canon sensors (excluding the upcoming 5DSR) You have 3 (three) stops of more room to push on the Sony CMOS sensor.
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Here's a linear comparison, ie linear matrix color no icc or dcp profile applied. Still have the issue, but it does look less bad thanks to that there are no hue twists. The pushed image is the one to the left.
It would be worthwhile to look into how C1 applies its ICC profiles, if it's before exposure correction there's an issue and one should probably roll one's own profile without hue twists. I don't have C1 on this computer so I can't test myself right now.
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No. I mean if you don't push too hard to have visible shadow noise then you don't have color cast. Compared against the CCD sensors and the current Canon sensors (excluding the upcoming 5DSR) You have 3 (three) stops of more room to push on the Sony CMOS sensor.
Ok. Can't argue against that as I haven't done any tests. Sounds quite reasonable though, less noise in general means better color fidelity.
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Sounds quite reasonable though, less noise in general means better color fidelity.
Yes, more signal, a higher S/N ratio, will allow a more stable demosaicing of color. Topaz Denoise even has a specific control for automatic Black point adjustment when lots of noise reduction is required in shadows.
Cheers,
Bart
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However, if you take a look at a sensor plus example, the results are very impressive indeed. This is a 1/125 shutter speed, and I needed it due to wind. I had a CL-PL on only, no CF. At iso 50, the recovery of shadows would have next to impossible without a bracketing, and with wind combining brackets becomes a task.
On this side by side, you have a IQ260 image, at ISO 200 in LE (long exposure mode). On the right is image with only the LCC applied and on the left I have worked up the shot. Notice the area under the main trees. In the right hand shot, it's basically almost black, and shows very little details. Remember this is iso 200. If you took a full resolution shot at 200, in normal or LE mode, these areas would be mushy and have little to no recoverable details. Where as the sensor plus image holds up to an almost 1.5 stop push. I over did it just a bit to see if I would see noise, but you don't. So, the sensor plus story is a good one and pretty impressive technology. However for my work, it only makes sense in the IQ180 as here you are using a 20MP image, which really has a lot more room for printing, especially when considering that I could stitch it.
The IQ260 only gives 15MP, which unless I do a nodal pan or a lot of stitching is going to stretch the resolution for a large print.
Looking back, I should have moved into the 180 instead of the 260 as the sensor plus images I have seen from the 180 are just as impressive.
With sensor plus, you don't see in loss in saturation at 400 up to 800, where as in full resolution mode, by iso 200 you are really going to see a large increase in noise in the shadows and considerable loss in both and saturation. If you push to iso 400 even in good light, you will see a loss in details and saturation enough that it may make more sense to use Sensor plus and have the better details and color/saturation, then try to uprez the image with one of the many software tools out there.
Paul
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Paul, do you find real advantage of the sensor+ tech, when compared against downsampled pictures at the same high ISO without using sensor+?
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Hi,
I just compared a normal exposure with an -4 EV exposure on on my P45+, the -4 EV exposure was corrected by a 4EV push in development. The two TIFFs were compared in Patchtool.
In the attached screen dump comparison images are shown with C1 v8 on the left and LR 5.6 on the right.
I see very little color shift on the P45+ at -4EV exposure.
Best regards
Erik
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This is nice. What kind of color passport did you shoot? I'd like to test it as well! ;)
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Paul, do you find real advantage of the sensor+ tech, when compared against downsampled pictures at the same high ISO without using sensor+?
Yes, it's pretty impressive, and something I really did not pay much attention to until I read some other posts here and elsewhere.
With the IQ260, you can shoot at iso 50 or 100 and expect pretty clean results unless the back has gotten hot which in the summer in my area does happen. But if you push the back to 200 you start to see noise in most of the shadows. You can bracket exposure at 200 and many times this will get you by on non shifted files, but when you start to move 15mm to 20mm, the shifted files really can suffer, enough that you really can't use them in a large print as the noise just really starts to degrade the image. If you go to iso 400 then things really get ugly, which non useable shadows, but you also see the falloff of finer details and the saturation will seem off a bit. It was this reason I had hoped that the IQ260, in LE mode for iso 200 and 400 would produce a much more useable file in full resolution but that has turned out NOT to be the case at all, if anything the images appear worse in normal exposure ranges. LE mode really only seems to help in shots longer than 2 minutes or more.
In sensor plus, at 200 and 400, the images appear to have much more normal color saturation and you do not lose the finer details. The shadows will pull up quite well, better in fact than at iso 50 in many cases. Colors look excellent and the files are extremely clean. Looking back, if I had moved to the 180, and had 20MP sensor plus, it would have been a much better decision for me.
I am shooting only with tech lenses, which provide for amazing details so the 15MP sensor plus files will uprez about 100% to a 30MP file before they start to show the usual uprez issues. If a better engine come out, (of which development seems to have stopped as more companies are putting out high res sensors), then these 15MP files could go a long way. They are very clean to start with, so you don't have a lot of trash pixels being uprez'd, (noise most often). I feel that iso 800 is the limit and that may be a push as often the files start to look like the 60MP full resolution files taken at iso 400, same issues.
Sensor plus is a good technology for sure. I had been in the MP race for so long, I never really worked with it until several shoots last year where I just could not operate at iso50.
Paul
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Hi,
It is an IT8 test target, the developed TIFF read by "scanin" program from ArgyllCMS and the data sets compared by Patchtool from BabelColor.
http://echophoto.dnsalias.net/ekr/Articles//darkrepro/20150225-CF046081.iiq
http://echophoto.dnsalias.net/ekr/Articles//darkrepro/20150225-CF046083.iiq
More details later today, when I have some time.
Best regards
Erik
This is nice. What kind of color passport did you shoot? I'd like to test it as well! ;)
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I see very little color shift on the P45+ at -4EV exposure.
I think you need to lower it considerably more. Look at those church benches of voidshatter's example shot, it's that kind of light level, ie almost black that is raised. One experiment could be to lower step by step until you start see color shifts to see where the limit is.
Also note that color profile may have hue shifts and might affect the result, so it would be better if you used a linear profile (ie only a matrix) when doing these experiments.
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I think you need to lower it considerably more. Look at those church benches of voidshatter's example shot, it's that kind of light level, ie almost black that is raised. One experiment could be to lower step by step until you start see color shifts to see where the limit is.
Also note that color profile may have hue shifts and might affect the result, so it would be better if you used a linear profile (ie only a matrix) when doing these experiments.
I agree, the least biased would be e.g. RawDigger data of the same very dark patch of a series of increasingly lower exposures. That would give the baseline data. On top of that one can stack any kind of demosaicing+profiling to see how the noise gets demosaiced into a non-neutral black point, or if something else is happening. My hypothesis is that it's the demosaicing of read-noise that can throw the blackpoint off neutral, and what the profiling does with that is anyone's guess.
At least RawTherapee allows to directly influence the RGGB BlackPoints, or one could resort to the demonstrated benefit of averaging multiple exposures, or even use a masked combination of regular ETTR exposure + Shadow exposure bracket, where we can align the exposures in Raw processing and replace the clipped regions of the shadow exposure with the ETTR data with a mask (the method that Hans Kruse recently mentioned in a thread here (http://forum.luminous-landscape.com/index.php?topic=96947.0), and Guillermo Luijk before that with his ZeroNoise (http://www.guillermoluijk.com/article/nonoise/index_en.htm) program).
Cheers,
Bart
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Hi,
I will make som more exposures with an ND-filter, and check with RawDigger. This was just a first attempt.
Best regards
Erik
I think you need to lower it considerably more. Look at those church benches of voidshatter's example shot, it's that kind of light level, ie almost black that is raised. One experiment could be to lower step by step until you start see color shifts to see where the limit is.
Also note that color profile may have hue shifts and might affect the result, so it would be better if you used a linear profile (ie only a matrix) when doing these experiments.
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I think most raw converters overdo noise reduction. I think it's because they want to make a clean pixel peep impression rather than thinking about how global color look in a print. Some grain is no problem for a print, but dead color is.
Concerning my observation that there might be not enough photons to give good colors in pushed shadows it's indeed a speculation, trying to explain what I see in many shots. I haven't yet looked at the above shots, but I guess 2 pushed stops may not be enough to show a significant effect, I'm thinking more like 4 stops.
What I often see in backlit landscape scenes with pushed shadows is that there's often a brown(ish)-centered palette in the pushed areas, color does not look as good in the well-exposed areas. I have not investigated in detail why this is, but have speculated that it's too few photons captured to make good color.
I sometimes see quite different color in pushed shadows. Here is one example from the Nikon D810 in a Scottish landscape and shot at ISO 64.
The first picture is a screen shot from Lightroom. The left hand is a -3EV exposure and the right hand is -1EV. Unfortunately I don't have more brackets. The edits on both exposures are exactly the same and same WB. The only difference is the exposure setting in Lightroom.
The second is the entire scene. This blended from the -3EV and -1EV and the bridge and landscape around it is all from the -1EV and has the right colors.
The third is the -3EV with no edits. So due to the very strong light the shadows are very much underexposed.
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Great example Hans! This is exactly the randomness of shadow noise. For me this is nothing really worth to worry about as I would never push it that hard. The Sony CMOS sensor (e.g. D810, IQ250 etc) has 3 stops of more room to abuse than any CCD digital backs. If I really have to push it that hard, I would just fix it using something like "Split Toning" in Lightroom or ACR. Landscape is subjective after all, just like the CCD fans would insist the "CCD-look" or "CCD-color" to be special, so even with some color cast it is totally fine and can be regarded as romantic.
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I sometimes see quite different color in pushed shadows. Here is one example from the Nikon D810 in a Scottish landscape and shot at ISO 64.
The first picture is a screen shot from Lightroom. The left hand is a -3EV exposure and the right hand is -1EV. Unfortunately I don't have more brackets. The edits on both exposures are exactly the same and same WB. The only difference is the exposure setting in Lightroom.
The second is the entire scene. This blended from the -3EV and -1EV and the bridge and landscape around it is all from the -1EV and has the right colors.
The third is the -3EV with no edits. So due to the very strong light the shadows are very much underexposed.
Hans nice shot!
Regarding the exposure don't you think -3 was a little too extreme and not required? I mean, from looking at the final result didn't -2 or even -1.5 work? or did it blow the highlights too much.
I think its tough to compare a CCD sensor and a Sony CMOS sensor since both need to be exposed differently (and even between CCDs) IMHO everything else being equal (base ISO, scene, lighting etc). I found that the CCD in my IQ160 held more highlight information with a smoother curve into blow highlights than the Nikon D800E (both at base iso). I could be more "aggressive" with the IQ160 exposure (brighter) compared to the Nikon (in which I had to protect the highlights with exposure more). With my Canon's it was somewhere in between those two. This is obviously before making any curve (or any) adjustments to the raw file, just a linear conversion. FWIW, the 645D was worse than all three. It blew the highlights pretty abruptly and earlier than all the other cameras.
Again, I don't know and really don't care why that happens (science / physics) but that is what happens when using the cameras for photography.
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Hans nice shot!
Regarding the exposure don't you think -3 was a little too extreme and not required? I mean, from looking at the final result didn't -2 or even -1.5 work? or did it blow the highlights too much.
I think its tough to compare a CCD sensor and a Sony CMOS sensor since both need to be exposed differently (and even between CCDs) IMHO everything else being equal (base ISO, scene, lighting etc). I found that the CCD in my IQ160 held more highlight information with a smoother curve into blow highlights than the Nikon D800E (both at base iso). I could be more "aggressive" with the IQ160 exposure (brighter) compared to the Nikon (in which I had to protect the highlights with exposure more). With my Canon's it was somewhere in between those two. This is obviously before making any curve (or any) adjustments to the raw file, just a linear conversion. FWIW, the 645D was worse than all three. It blew the highlights pretty abruptly and earlier than all the other cameras.
Again, I don't know and really don't care why that happens (science / physics) but that is what happens when using the cameras for photography.
Ken,
I have attached the full image of the -1EV that I merged with the -3EV. I bracketed the shots as I always do and then I choose in Lightroom which exposure is optimal (the most exposed with no essential highlights clipped). If the optimal exposure looks good after editing then I'll just go with that. If not I will blend the shot with another one from the bracketing sequence (if it exists). If I find the noise in the shadows a bit too much then I will copy the edits from the exposure I have edited to all other pictures in the bracketing sequence (including all parameters) and then I will match the exposure (shift-alt-cmd-M). The I will check the highlights and shadows in the other exposures. If none can be used standalone and this does not happen that often, then I will do the blending. The blending of two exposures (one for then highlights and one for the shadows) will be done in Photoshop as layers. This is easy to do since the edits is exactly the same and the exposure difference has been eliminated. It's just a few clicks and shortcuts in Photoshop and it is done.
This is basically my shooting style no matter if I shoot Canon or Nikon. For the Phase One bracketing was slow and tedious but I did it when needed. On the Canons and Nikons I can fire off the bracket sequence in continous mode in live view for at least focus lengths less than 100mm. For more than that I need to be more careful.
I like to know what happens and what is the explanation for things, but my shooting style is optimized towards not having to deal with histograms and exposure compensation, filters etc. I want a completely mechanical style where the only thing I concentrate on is to find the best viewpoints, the best compositions and sometimes this is within minutes and time is precious.
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Great example Hans! This is exactly the randomness of shadow noise. For me this is nothing really worth to worry about as I would never push it that hard. The Sony CMOS sensor (e.g. D810, IQ250 etc) has 3 stops of more room to abuse than any CCD digital backs. If I really have to push it that hard, I would just fix it using something like "Split Toning" in Lightroom or ACR. Landscape is subjective after all, just like the CCD fans would insist the "CCD-look" or "CCD-color" to be special, so even with some color cast it is totally fine and can be regarded as romantic.
Thanks and I agree very much. I did not consider the -3EV shot as ruined even though I pushed it hard, but found that the blended result was better and what I wanted to preserve. In fact I'm not sure anybody would notice the flaws in the -3EVF shot :)
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Thanks and I agree very much. I did not consider the -3EV shot as ruined even though I pushed it hard, but found that the blended result was better and what I wanted to preserve. In fact I'm not sure anybody would notice the flaws in the -3EVF shot :)
Wow I just noticed that you are the famous mighy Hans at 500px! I don't follow many there but I started following your shots a long while ago! Damn your telephoto landscape shots are just too great which really makes it hard to justify heavy investments into MFDB! I would perhaps go back to Canikon again ;D
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Wow I just noticed that you are the famous mighy Hans at 500px! I don't follow many there but I started following your shots a long while ago! Damn your telephoto landscape shots are just too great which really makes it hard to justify heavy investments into MFDB! I would perhaps go back to Canikon again ;D
Thanks :) I also have a few there from the Phase One. E.g. this one https://500px.com/photo/58213766/lenticular-clouds-forming-over-sassolungo-by-hans-kruse
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Hi,
I had the pleasure to take part in one of Hans's workshops.
As a small observation, I just happen to have a small exhibition hanging on the theme Mountains, Valleys and Water. Albeit I have been shooting MFD for something like 20 months, none of the MFD images that made it to that exhibition. I don't know why, honestly. One reason was probably that I don't carry the MFD kit for long walks.
The images are here: http://echophoto.dnsalias.net/ekr/Articles/Exhibitions/BergDalOchVatten_1/
I have shot some very nices images with the MFD stuff at home.
Best regards
Erik
Wow I just noticed that you are the famous mighy Hans at 500px! I don't follow many there but I started following your shots a long while ago! Damn your telephoto landscape shots are just too great which really makes it hard to justify heavy investments into MFDB! I would perhaps go back to Canikon again ;D
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Hi,
A longer answer…
Just to say, I have not really seen colour shifts in the darks on my P45+, but decided to look into that a bit. My background is in engineering, so I have a tendency to look fora feasible explanations for any observation. With MFD there are many myths, little observations and very few explanations.
I have a couple of tools that I originally acquired to do "sanity checks" on my printer profiles. One of those tools is PatchTool from BabelColor. That tool can read a pair of CGATS files and do a graphical comparison between the colours. Very useful.
A while ago I got interested in looking into the accuracy of colour reproduction on my P45+ compared to my Sony Alpha 99, and I was looking into getting a test chart with more colours than the classic Colour Checker. The Colour Checker SG would be a natural alternative, but it is a bit expensive and reference values are not easy to obtain.
Than I realised I could use an IT8 colour chart. It has a lot of fields and covers most parts of Adobe RGB and they always come with reference data:
http://www.targets.coloraid.de
I used the C1 target, the reference data is here: http://echophoto.dnsalias.net/ekr/Articles/darkrepro/Ref/R050301_remap.txt (note the fields are remapped for easier use)
Now, I made 5 different shots with 0, -2EV, -4EV, -7EV and -6EV exposures (the last two using a 3X ND filter)
Those images are here: http://echophoto.dnsalias.net/ekr/Articles/darkrepro/Originals
I made raw conversions from the 0EV and -4EV images using both LR5 (using process version 2010) and Capture One compensating for underexposure, saving the results as 16 bit TIFFS.
Next step was to use the "scanin" program from Argyll CMS to read the IT8 field values from TIFF files into CGATS files.
The last step was to read the reference file and the CGATS files from scanin into PatchToo and evaluate the differences.
I didn't go beyond -4EV as I wanted to compensate for the underexposure in LR, and LR with PV 2010 only goes to +4EV compensation
The include screen dumps from RawDigger show the three darkest grey patches in RawDigger from the -6EV exposure.
I would think that once exposure is so small that readout noise "contaminates" shot noise there would be a colour shift as the different channels would be differently affected, and that colour shift would vary by white balance and CFA design.
Best regards
Erik
This is nice. What kind of color passport did you shoot? I'd like to test it as well! ;)
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Thanks :) I also have a few there from the Phase One. E.g. this one https://500px.com/photo/58213766/lenticular-clouds-forming-over-sassolungo-by-hans-kruse
Obviously you have got more keepers from Canikon gear! Now Canon offers the 5DSR with choices like 11-24mm f/4 L and we also had the light-weighted 70-200mm f/4 L. If I don't shoot long exposures (hence no alignment issues with filters), then with your bracketing technique to deal with high dynamic range I see no problem with the predicted inferior dynamic range of the 5DSR. It is even harder to justify MFDB now.
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This is great Erik. I have the same color passport as yours. When I have my lens back I will shoot it with an IQ250 and ask you to run the color check program :)
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All subjective, but my 1 month with my Credo 60 sees me feeling as follows:
Credo - Protect the shadows
Canon - Protect the highlights.
ie as Ken mentioned, I feel I can use longer exposures with the credo in comparison to the Canon (given equivalent aperture/iso combo)
I haven't used a sony cmos, but would like to soon
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Hi,
What Hans is advocating is to "repair" highlights using a lower exposure rather than repairing the "shadows" using a higher exposure. It is pretty smart, as the highlights are often sky/sunlight phenomena which mix well. He was kind enough to demonstrate it on my own images and he got better results than I was able to achieve.
I have been shooting Sony's since 2006, and "never" had issues with DR, it was always there when needed. This is of course a moving target.
Another side of the coin is that tone mapping is needed to properly render a high DR exposure.
I started using HDR-mapping on single exposures, but I gave up on the technique when LR4 with PV 2012 arrived. I felt that LR 4 did a much more subtle tone mapping than what I could achieve with Photoshop tools albeit I feel I would like to have a bit more of control.
Best regards
Erik
At least RawTherapee allows to directly influence the RGGB BlackPoints, or one could resort to the demonstrated benefit of averaging multiple exposures, or even use a masked combination of regular ETTR exposure + Shadow exposure bracket, where we can align the exposures in Raw processing and replace the clipped regions of the shadow exposure with the ETTR data with a mask (the method that Hans Kruse recently mentioned in a thread here (http://forum.luminous-landscape.com/index.php?topic=96947.0), and Guillermo Luijk before that with his ZeroNoise (http://www.guillermoluijk.com/article/nonoise/index_en.htm) program).
Cheers,
Bart
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Hi,
In my experience MFD uses a pair of tricks to protect highlights
- Overrating ISO
- Biasing in processing
If you use Capture One, try out film curve versus linear response. With "film curve" the images will be far to bright so you learn to underexpose to protect highlights.
The only difference between the enclosed images is that the brighter one uses "Film Curve" while the darker one uses "Linear Response".
The last image shows the "true" histogram of that shot, using RawDigger which shows the actual data in the raw file. Very clearly, that image could take one more EV of exposure without clipping, but I am pretty sure that camera histogram was on the brink of overexposure, as I always expose ETTR
Best regards
Erik
All subjective, but my 1 month with my Credo 60 sees me feeling as follows:
Credo - Protect the shadows
Canon - Protect the highlights.
ie as Ken mentioned, I feel I can use longer exposures with the credo in comparison to the Canon (given equivalent aperture/iso combo)
I haven't used a sony cmos, but would like to soon
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Erik, could you test color shift of shadow pushed by 4ev on your Sony camera (preferably a sensor similar to the IMX094)? Thanks!
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Hi,
I have already done that, but I was not happy with exposure so I will remake that experiment. Coming in a couple days. The Sony I intend to test is the Alpha 99.
Best regards
Erik
Erik, could you test color shift of shadow pushed by 4ev on your Sony camera (preferably a sensor similar to the IMX094)? Thanks!
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Hi,
What Hans is advocating is to "repair" highlights using a lower exposure rather than repairing the "shadows" using a higher exposure.
Indeed, but he uses the shadows exposure (with better shot noise) for the majority of the image, except for the clipped highlights which get replaced by the ETTR exposure. Both Raw conversions were synchronized for exposure setting, so the blend between them is virtually seamless. t works quite well, also because one doesn't have to do a huge amount of additional tonemapping compared to a single exposure. It's just that the shadows and mid-tones have been better exposed, have lower noise, and thus allow more manipulation.
It is pretty smart, as the highlights are often sky/sunlight phenomena which mix well.
Yes, it does work well. The only issue can be e.g. moving clouds that could have poorer registration between images.
Another side of the coin is that tone mapping is needed to properly render a high DR exposure.
Yes, but then all images require some sort of tonemapping, because a print has a much lower DR than e.g. a backlit panel or a display can have.
Cheers,
Bart
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"Linear curve" in most commercial raw converters are usually still not linear, a common thing they do is to clip away the last bit of highlights, and from the Capture One example above it seems like it does exactly that. It's prbably recoverable by just lowering exposure though.
I did a test yesterday with C1 to check if the ICC profile is applied before or after exposure adjustment (and curve), and it's applied after. I kind of new this already as you can export a TIF with the camera ICC, meaning that the ICC must be applied in the end. Phase One's ICC profiles has hue twists by the way, just as Adobe's DCPs typically have. I think Phocus own profile format is wihtout hue twists, but I haven't verified it for sure.
Anyway, this is a weakness of the ICC format, with Adobe DCP you can apply one correction at the raw before exposure adjustments tonemapping etc, and then apply one after. The first is intented to correct color (and they recommend against hue twists there), the other is intented to apply a look (and generally contains hue twists, eg saturation increase in shadows as many like that).
If there is a static color shift in the darkest shadows, that could be corrected with a DCP profile (using hue twists in the first HueSatDelta correction table), but it's not possible to correct with C1's ICC. In any case there's noone that does it today, but it could be an interesting new development in camera profiles. If it's like voidshatter says that the cast varies over time it's not possible to correct anyway though.
RawTherapee supports C1 ICC files, but it's color pipeline is designed such that profiles should only correct for accuracy and look is up to the user using the raw converter tools (which is a flow I prefer for my own photography), this means there is only one profile application step and that is before any adjustments, so if you push a heavily underexposed file the hue twists in the ICC will make it all look wrong, so to use C1 ICCs and indeed Adobe DCPs with a "look" in RT with desired result you need to have a file which has the right exposure from the start. RT's own DCPs are without hue twists and designed for accuracy at D50.
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Hi,
I shot some decent samples with my P45+ and my Sony Alpha 99 SLT.
Exposures were 0, -2, -4, -6 and -7 EV. The two lowest exposure were achieved using ND filter. The 0, -4EV was using studio flash and varying intensity.
Raw images are here: http://echophoto.dnsalias.net/ekr/Articles/darkrepro/RawFiles/
This image shows tonal shifts caused by underexposing 4EV. P45+ shows less tonal shift and SLT99 more. All processing I tried gives this result.
CGATS files are here: http://echophoto.dnsalias.net/ekr/Articles/darkrepro/CGATS
(http://echophoto.dnsalias.net/ekr/Articles/darkrepro/ScreenDumps/4EV_under,_tonal_shifts.png)
This is 0EV and -4EV comparison on P45+ in Lightroom
(http://echophoto.dnsalias.net/ekr/Articles/darkrepro/ScreenDumps/P45_4EV.png)
Original: http://echophoto.dnsalias.net/ekr/Articles/darkrepro/ScreenDumps/SSLT99_4EV.png
And this is 0 and -4EV comparison on SLT 99 in Lightroom
(http://echophoto.dnsalias.net/ekr/Articles/darkrepro/ScreenDumps/SSLT99_4EV.png)
Original: http://echophoto.dnsalias.net/ekr/Articles/darkrepro/ScreenDumps/SSLT99_4EV.png
For some reason, the SLT99 images are in 12 bit, the Sony cameras choose between 14-bit and 12-bit a bit arbitrarily, single exposure used to be 14-bits. I did some raw digging, but I have not found anything sensational.
Best regards
Erik
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Great tests! The IMX128 seems to hold strong. Would be curious to see how IMX094 performs (preferably on a lossless one such like the D800E).
If you ever turn on any of the following settings on a Sony EVF camera you would get 12-bit RAW (actually around 1300 levels for each channel, 10.4-bit equivalent) instead of 14-bit RAW (actually around 1700 levels for each channel, 10.7-bit equivalent):
Long exposure noise reduction (darkframe NR)
B mode (bulb mode)
continuous shooting
speed priority continuous shooting
silent shutter (for the A7S)
A while ago when I did an article about how the lossy compresison of the Sony EVF camera impacts image quality, I did a stress test on shadow push of long exposure shots. Below shows a comparison between the A7 (left) and the D610 (right):
(https://1xzpta.dm2302.livefilestore.com/y2p841yire_CNjjmg3YViN2ABGp3W7833MZdM2Y6mf5B0WWQsoOkllaU5pXto__fpUhfjtY-7urXH5qzHSXujB6opvE42oMRNnyLjv5qIZD509Jy4n4qrpslbW-ngyJkJ3ysZiJQUHO_LRjYU5LgZ-NjQ/7%201.JPG?psid=1)
As can be seen, even if the same neutral area was selected for the "Pick White Balance Tool", the shadow still had different degree of color casts. Note that the above was both multi-sampling (temporal noise reduction) from 30 frames each. Our first speculation was that the lossy compression of the Sony RAW had too many 0s (zero's) in the shadow, resulting in demosaicing failures regarding color fidelity.
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Hi,
If the IMX094 is the one used in the 36MP cameras it seems to be an (even) better performer, although it has smaller pixels. I have no access to any Nikon FF, unfortunately. I know a lady who has a D810 (or some other of the 800 models), but I am pretty sure she is using it for shooting and earning money and is less than enthusiastic about pixel peeping.
Once Sony has next generation high pixel camera I will probably buy. I don't want to switch systems, and I feel that Sony finally got it right with the A7 models. Hopefully they will make an A9.
Best regards
Erik
Great tests! The IMX128 seems to hold strong. Would be curious to see how IMX094 performs (preferably how a lossless one such like the D800E).
If you ever turn on any of these on a current Sony camera you would get 12-bit RAW (actually around 1300 levels for each channel, 10.4-bit equivalent) instead of 14-bit RAW (actually around 1700 levels for each channel, 10.7-bit equivalent):
Long exposure noise reduction (darkframe NR)
B mode (bulb mode)
continuous shooting
speed priority continuous shooting
silent shutter (for the A7S)
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Hi,
If the IMX094 is the one used in the 36MP cameras it seems to be an (even) better performer, although it has smaller pixels. I have no access to any Nikon FF, unfortunately. I know a lady who has a D810 (or some other of the 800 models), but I am pretty sure she is using it for shooting and earning money and is less than enthusiastic about pixel peeping.
Once Sony has next generation high pixel camera I will probably buy. I don't want to switch systems, and I feel that Sony finally got it right with the A7 models. Hopefully they will make an A9.
Best regards
Erik
I have added more info in my reply above (a comparison between an A7 and a D610).
I agree with you that the Sony A series is really a success. I will also most likely buy an A9. The portability is hard to resist!
I have a D800E by my hand. Would it work if I shoot the X-rite color check passport and upload the RAW files to you?
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Hi,
yes, of course, but my colour shift tests are based on the C1 target on this page: http://www.targets.coloraid.de
If shooting the Color Checker Passport, please try to expose ETTR so the white field is near saturation.
Thanks for the info Sony exposure modes. My images used to be "14-bit".
Best regards
Erik
I have added more info in my reply above (a comparison between an A7 and a D610).
I agree with you that the Sony A series is really a success. I will also most likely buy an A9. The portability is hard to resist!
I have a D800E by my hand. Would it work if I shoot the X-rite color check passport and upload the RAW files to you?
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IQ250 RAW files: https://www.dropbox.com/sh/fgircd45mbjf62r/AAC2evO6UQMAOxmQpLccyzmfa?dl=0
(https://1xzpta.dm2302.livefilestore.com/y2p35RpknVEgc2V6DrVjnmSXektrNfGZoDz4eEsyopAHWSc-JjVs6poqWCsAkbjHY6fv-GYRJqujG1UkHZaj7cGPTBHYOzuJ-Z2kdEHaup2ZHC15WYxPq_SyHDXyknrF9ca-eJv5w8pcNRmRguGv3kyEg/shadow_push_color_check_1.JPG?psid=1)
(https://1xzpta.dm2302.livefilestore.com/y2pTK_mMzXFzQZ7Y5v8-04t-3Ox6IXWn2JfQy88JCNGtMQgSNQAd4FV3fnX8boc9ku3m0ND8V4Oqkn8IcvC7XjogQ3BI5AePI5sVmC85bE2CTm-25iZbbqXx3eoNJQed_OKQAGL0hTRXQfhsmG8YYYEWA/shadow_push_color_check_2.JPG?psid=1)
(https://1xzpta.dm2302.livefilestore.com/y2pm5COW15j0Sxd4lH-tDmaGf_RK75gSvc8kN4JidsOpGpElhd9fpf6fpPp_nab-esK6bmTpveVeO8U-SiCAsDv7QvJWlSzxGICrjsbgEV7XK3mzv0qKVyp5gwqyR65E0nVKHGDOUrJX7rlDrygQYwnfg/shadow_push_color_check.JPG?psid=1)
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Hi "Void",
Downloading them right now. Will take a look the coming few days and report back.
BTW, thanks for sharing your comparison between Sony and Nikon. Personally, I don't think it is the compression that is causing the difference, but it is interesting to see how much cleaner the Nikon data is.
Best regards
Erik
IQ250 RAW files: https://www.dropbox.com/sh/fgircd45mbjf62r/AAC2evO6UQMAOxmQpLccyzmfa?dl=0
(https://1xzpta.dm2302.livefilestore.com/y2p35RpknVEgc2V6DrVjnmSXektrNfGZoDz4eEsyopAHWSc-JjVs6poqWCsAkbjHY6fv-GYRJqujG1UkHZaj7cGPTBHYOzuJ-Z2kdEHaup2ZHC15WYxPq_SyHDXyknrF9ca-eJv5w8pcNRmRguGv3kyEg/shadow_push_color_check_1.JPG?psid=1)
(https://1xzpta.dm2302.livefilestore.com/y2pTK_mMzXFzQZ7Y5v8-04t-3Ox6IXWn2JfQy88JCNGtMQgSNQAd4FV3fnX8boc9ku3m0ND8V4Oqkn8IcvC7XjogQ3BI5AePI5sVmC85bE2CTm-25iZbbqXx3eoNJQed_OKQAGL0hTRXQfhsmG8YYYEWA/shadow_push_color_check_2.JPG?psid=1)
(https://1xzpta.dm2302.livefilestore.com/y2pm5COW15j0Sxd4lH-tDmaGf_RK75gSvc8kN4JidsOpGpElhd9fpf6fpPp_nab-esK6bmTpveVeO8U-SiCAsDv7QvJWlSzxGICrjsbgEV7XK3mzv0qKVyp5gwqyR65E0nVKHGDOUrJX7rlDrygQYwnfg/shadow_push_color_check.JPG?psid=1)
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Anyway, this is a weakness of the ICC format, with Adobe DCP you can apply one correction at the raw before exposure adjustments tonemapping etc, and then apply one after. The first is intented to correct color (and they recommend against hue twists there), the other is intented to apply a look (and generally contains hue twists, eg saturation increase in shadows as many like that).
format or converter... nobody prevents your converter to be written in such manner so that it will use ICC container to store pre and post adjustment corrections... icc container can store multiple sets of color transforms - you might argue that injection of converter adjustments (done by converters code, reflecting user action in UI and not guided by purely the data in icc container) is not exactly what ICC (organization) prescribed, but then who cares really - just document the use... no ?? what do you say
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format or converter... nobody prevents your converter to be written in such manner so that it will use ICC container to store pre and post adjustment corrections... icc container can store multiple sets of color transforms - you might argue that injection of converter adjustments (done by converters code, reflecting user action in UI and not guided by purely the data in icc container) is not exactly what ICC (organization) prescribed, but then who cares really - just document the use... no ?? what do you say
Good point, that can work. ICC profiles are already used today in "non-standard" ways when used for photography. The ICC profile expects some sort of pre-processing, the Capture One native ICC profiles require a 1.8 gamma to be applied to the input for example if I remember correctly.
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Good point, that can work. ICC profiles are already used today in "non-standard" ways when used for photography. The ICC profile expects some sort of pre-processing, the Capture One native ICC profiles require a 1.8 gamma to be applied to the input for example if I remember correctly.
Hi Anders,
That has been mentioned by some, but that's only a very rough approximation.
For example, the profile for my 1Ds3 is reasonably well (an R^2 of 1.0 would be perfect)
fitted by something close to a gamma of 1/1.94 (the c-parameter in the attached curve fit).
Canon 1Ds Mark III, Green TRC from generic profile by Phase One
Formula: y = b*(x-a)^c*exp(-(x-a)/d)
Parameters:
a = 2.89348
b = 3816.21694
c = 0.51478
d = 1.11691E13
R^2: 0.99808
But indeed, there are assumptions involved which the Raw converter should convert the data to.
Cheers,
Bart
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Thanks for the IQ250 examples voidshatter. There's impressive performance in there. I assume the 1726 is the +0? (the 1727 is otherwise almost perfect ETTR on the raw level).
Using linear color conversion in RT shadow neutral color shift towards green is evident at 1720 (+6) but also slightly visible at 1722 (+4), then becoming invisible.
I looked at some Aptus 75 shots I did for this test: http://www.ludd.ltu.se/~torger/photography/noise-test.html back in 2012, and I'd say that although the +4 shot is noisier and the +6 shot is unusable (tiling visible), the visual color stability is about the same, ie a cast starts showing (also green on the Aptus) but not really much more evident on the Aptus 75 than on the IQ250.
It does re-inforce my view that what you gain with the Sony sensor compared to old-school CCDs is about 2 stops, but the value of those extra two stops is a bit limited due to the weaker color fidelity down there. I guess my conclusion is that the CCDs have quite good signal, they just overlay it with lots of read noise which takes away some shadow push capability.
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The ICC profile expects some sort of pre-processing
why ? you can bake the curve in ICC trcs/luts and feed totally linear (g1) demosaicked data in the pipeline - if your converter allows/does that
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Hi Anders,
That is what I would expect from spec sheets and DxO data. But, darks are darks and I don't think we look for good colour in barely visible parts of the image. What we want to see is a good and nice poisson distributed noise without colourful salt and pepper noise.
Best regards
Erik
…
It does re-inforce my view that what you gain with the Sony sensor compared to old-school CCDs is about 2 stops, but the value of those extra two stops is a bit limited due to the weaker color fidelity down there. I guess my conclusion is that the CCDs have quite good signal, they just overlay it with lots of read noise which takes away some shadow push capability.
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That has been mentioned by some, but that's only a very rough approximation.
I'm a bit rusty on this aspect of ICC profiles but I think it works like this in C1, the TRC curves are not used (you can strip away them and it will make no difference), instead conversion is made with the A2B0 table which converts from RGB to Lab with 1.8 gamma, so if you work in linear gamma floating point you need to apply gamma 1/1.8 (plus an expected film curve) before conversion, and then revert curve and gamma if you want to continue in linear space.
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Thanks for the IQ250 examples voidshatter. There's impressive performance in there. I assume the 1726 is the +0? (the 1727 is otherwise almost perfect ETTR on the raw level).
Using linear color conversion in RT shadow neutral color shift towards green is evident at 1720 (+6) but also slightly visible at 1722 (+4), then becoming invisible.
I looked at some Aptus 75 shots I did for this test: http://www.ludd.ltu.se/~torger/photography/noise-test.html back in 2012, and I'd say that although the +4 shot is noisier and the +6 shot is unusable (tiling visible), the visual color stability is about the same, ie a cast starts showing (also green on the Aptus) but not really much more evident on the Aptus 75 than on the IQ250.
It does re-inforce my view that what you gain with the Sony sensor compared to old-school CCDs is about 2 stops, but the value of those extra two stops is a bit limited due to the weaker color fidelity down there. I guess my conclusion is that the CCDs have quite good signal, they just overlay it with lots of read noise which takes away some shadow push capability.
In your ancient test the D7000 (a smaller version of the IQ250/D800E) already outperformed the 5D2 and the Leaf CCD. Far before you see color casts the SNR becomes an issue first. If you try long exposure you would see how limited the CCD backs are. It wouldn't be just 2 stops. It would be something like 3 stops, which is a big deal.
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I'm a bit rusty on this aspect of ICC profiles but I think it works like this in C1, the TRC curves are not used (you can strip away them and it will make no difference), instead conversion is made with the A2B0 table which converts from RGB to Lab with 1.8 gamma, so if you work in linear gamma floating point you need to apply gamma 1/1.8 (plus an expected film curve) before conversion, and then revert curve and gamma if you want to continue in linear space.
but you can strip LUT and leave TRCs... now color editor won't work then... and as far as I remember you can have XYZ PCS and it still will work (so Lab PCS is not a must for profile to work in C1, at least it still works)
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Hi "Void",
BTW, thanks for sharing your comparison between Sony and Nikon. Personally, I don't think it is the compression that is causing the difference, but it is interesting to see how much cleaner the Nikon data is.
Best regards
Erik
Have you really checked the RAW data of the shadow in the Sony RAW with lossy compression? It has many rows of pure 0s (zeros). I bet it has something to do with demosaicing failure, i.e. making it more difficult to guess the real color. That's why I always observed more color cast in the pushed shadow for Sony EVF cameras.
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Hi,
I looked at the colour shift between the ETTR exposure and the 4 steps below with both Lightroom 5.7 and Capture One 8.x.
What I see is that Capture One has little colour shift with 4 EV exposure change while Lightroom has more change. This is not due to exposure dependent hue-shifts as I used different profiles in Lightroom and I ha a similar colour shift.
Lightroom left, Capture One on the right.
Best regards
Erik
IQ250 RAW files: https://www.dropbox.com/sh/fgircd45mbjf62r/AAC2evO6UQMAOxmQpLccyzmfa?dl=0
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Thanks! Could you try Capture One for P45+ as well please?
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Quick and dirty, P45+m Capture One v8, 0 EV vs +4EV shift
At least regarding numbers it seems your IQ-250 comes out on top…
Best regards
Erik
Thanks! Could you try Capture One for P45+ as well please?
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Thanks! So scientifically there is no evidence that the colors from pushed shadow out of a current Sony CMOS sensor (e.g. D7000/D800E/IQ250/645Z etc) look more disappointing than those pushed from the CCD shadows.
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Hi,
I would call it weak experimental evidence rather than scientific proof…
I would suggest it may be worthwhile to go a bit deeper into this. I may do it if I find some time.
Best regards
Erik
Thanks! So scientifically there is no evidence that the colors from pushed shadow out of a current Sony CMOS sensor (e.g. D7000/D800E/IQ250/645Z etc) look more disappointing than those pushed from the CCD shadows.