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Author Topic: An example of the shadow limitations of a MF CCD  (Read 16141 times)

AlterEgo

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Re: An example of the shadow limitations of a MF CCD
« Reply #60 on: March 06, 2015, 07:00:53 pm »

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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voidshatter

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Re: An example of the shadow limitations of a MF CCD
« Reply #61 on: March 08, 2015, 06:11:58 am »

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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ErikKaffehr

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Re: An example of the shadow limitations of a MF CCD
« Reply #62 on: March 09, 2015, 04:11:38 pm »

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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voidshatter

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Re: An example of the shadow limitations of a MF CCD
« Reply #63 on: March 09, 2015, 04:37:17 pm »

Thanks! Could you try Capture One for P45+ as well please?
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ErikKaffehr

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Re: An example of the shadow limitations of a MF CCD
« Reply #64 on: March 11, 2015, 03:13:56 am »

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?
« Last Edit: March 11, 2015, 03:41:00 am by ErikKaffehr »
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voidshatter

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Re: An example of the shadow limitations of a MF CCD
« Reply #65 on: March 11, 2015, 06:03:27 am »

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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ErikKaffehr

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Re: An example of the shadow limitations of a MF CCD
« Reply #66 on: March 11, 2015, 04:00:33 pm »

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.
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