Hi List,

Last year I was comparing the grain at high ISOs on a couple of DSLRs (
whilst we waited for some wildlife, in a forest). 

In an idle moment at the weekend, I tried the same experiments, but
figured that the way to do it would be to use a lens cap and compare
pure noise from different cameras. The results are quite interesting,
but of course hard to quantify.

Taking a shot from a DSLR of pure darkness yields little information
until the file is taken into photoshop and the contrast increased so
that the actual noise can be clearly seen, very much like grain on an
high ISO film.

My question:

1. Is there any way to count or quantify grain / noise as a percentage
of a frame without printing / counting and expensive equipment?

2. Taking the file to 95% contrast, the noise is nomal, at 100% the
black and white turns to pure white - does that make sense? It seems
correct to me, but I have doubts.

Any interesting thoughts would be much appreciated.

Nick WB


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Nick Wilcox-Brown 
W: www.NickWB.com
   

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