a7rii compressed vs. uncompressed quality

[rainer_v]

i wanted to see the difference among the new uncompressed and compressed raws and took some shots 5 and 6 stops underexposed. you can take your own conclusions , here are the raws:
www.tangential.de/downloads/151022-test-a7r2.zip

i took two shots, each uncompressed and compressed, 5 and 6 stops underexposed.
also one shot uncompressed and compressed, each one time with silent mode on and silent mode off.

My conclusions are: at least one stop better color fidelity uncompressed, you can see this in the shadows, as well as the compressed shots show strong banding in this dark zones.
silent mode eats at least one stop, the noise floor is considerable higher with s-mode on in compressed and uncompressed mode, so this is still 12bit.
If this differences are important? ofcourse they are.. otherwise all this dr measurements would be pointless, but for certain kinds of photography its great to have so high dr as sony and nikons are having.
Probably with uncompressed files the a7rii will equal or surpass the d810 now in dr, but this has to be compared by whoever it cares

[PeterAit]

Thank you so much. Given that I do most of my photographs 5 or 6 stops underexposed, this is truly important information.

[alan_b]

Thank you so much. Given that I do most of my photographs 5 or 6 stops underexposed, this is truly important information.

Thank you so much. Given that I have areas in my photographs 5 or 6 stops below middle gray, this is useful information.

Thanks Rainer, I tend to layer a +3 exposure to clean up deep shadows in interiors, even with Sony/Nikon wonder sensors.  Improvements to noise in those regions is appreciated.

[rainer_v]

Thank you so much. Given that I have areas in my photographs 5 or 6 stops below middle gray, this is useful information.

Thanks Rainer, I tend to layer a +3 exposure to clean up deep shadows in interiors, even with Sony/Nikon wonder sensors.  Improvements to noise in those regions is appreciated.

so it is ... its not the question to underexpose shots but to similate high dynamic scenes as interiors or exteriors against sunlight and so on ...

[rainer_v]

... and i see as well the biggest difference in the color resolution in the deep shadows. The compressed files show in this zones strong banding, the uncompressed not. I suppose this can show up under certain circumstances in brighter regions or with very smooth color gradations as well, also it seems to be veryy rare. Or with strong post processing.
There was a very bad landscape image spread over the web some days after the releaße of the a7rii, which showed heavy color banding,- the compression could be its explanation.

For me its not a question which files i will use in future ...

[Huib]

Buffer Test with compressed and uncompressed RAW
https://www.youtube.com/watch?v=ykXCQnzXm-8

[Hans Kruse]

so it is ... its not the question to underexpose shots but to similate high dynamic scenes as interiors or exteriors against sunlight and so on ...

If you really need 5-6 stops I would argue that you would get better results with merging multiple exposures. 6 stops underexposure from clipping raised 6 stops in PP is like shooting ISO 6400 in camera which creates noise and lack of details. So unless blending is not possible I don't see the point in raising exposure that much except in cases of rescue of a bad shot.

[adrian tyler]

rainer, do you convirt to dng first?
the sony arw a7rii files typically come in at about 85mb each.
however converting to dng they end up about half that size.
that is quite a considerable difference...

[rainer_v]

I am not sure that the dng conversion is lossless, differnt opinions in the net about this, adobe claims it looses some quality. Storage space isnt expensive, so i hold the original raws.

[AFairley]

I am not sure that the dng conversion is lossless, differnt opinions in the net about this, adobe claims it looses some quality. Storage space isnt expensive, so i hold the original raws.

Sources?

[rainer_v]

Sources?

Reading it "here and there" in the net, maybe its wrong!

[NancyP]

Hans, a classic example of dynamic problems that may not blend easily are grass or leaves against a very bright background. The wretched things move between exposures!