Question about RAW files bit depth (8 vs 16)

[Sunseeker1975]

Hi All,

I have a simple question about bit depth, arising from an observation. I tried to make it as clear as possible with a simple video:

I would be very happy to get some feedback.

Thank you a lot in advance!

Enrico

 

[thebestcpu]

Hi @Sunseeker1975

Unfortunately the way video compresses information does not make the issue very clear.
However, I can still tell by taking the two images and overlaying them that there is some differences with more graytones when you use 16 bit mode.

I suggest you turn on your histogram and look at the 8 bit version and 16 bit version. You will see that there are many more peaks in the histogram (posterizing) in the 8 bit image vs the 16 bit image. Its just a bit more subtle. Probably obscured my guess from the subject not being in tack sharp focus as well as the sensor noise.

That's my feedback
John Wheeler

 

[Sunseeker1975]

Hi @thebestcpu

Thank you for the prompt reply!

Indeed, checking the histogram some differences arise. I captured this in the attached image (another range of the spectrum was amplified in this case), with 3 different histogram for each case.
What can be misleading is the fact that in both cases the "tight Curves" operation saturate to 32768 (or 255) each RGB channel.

Still, I expected that boosting the shadows in a 16bit vs 8bit scenarios would have a 256 times better result! Well, not really, as Canon EOS 5D mk4 has 14 bit RAW (the last 2 bits of the 16 is always 0), so maybe 64 times better. I mean 64 times more gray steps in the body of the bee, if I boosted the shadows. Or in the bee's background in the case of the image below...

What do you (or others) think? Was I just dreaming?