What is this fascination with iso6400?

Started Feb 11, 2013 | Discussions thread
dosdan Contributing Member • Posts: 512
Re: What is this fascination with iso6400?

John Sheehy wrote:

dosdan wrote:

So please explain how an expose that has a 4x worse shot noise SNR ( a fact of life due to the quantum nature of light) can have the same "quality" as a ISO50 image with a 4x better shot noise SNR?

Simple. You just include a variable neutral density filter over the sensor, and adjust it accordingly so that all ISOs have the same photosite exposure.

But, besides winning an argument, what advantage would "Constant Quality" mode offer? 

In this example, "Constant Quality" = ISO6400 quality (assuming this was the ISO level where the minimum ND filtering was applied.)

Assuming the base ISO was ISO100 and the max ISO covered by the "Constant [poor] Quality" mode was ISO6400, this would mean that the FWC could be pruned back to 1/64th of its current capacity.


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