Quote Originally Posted by HDNitehawk


Using the same lens and adjusting distance should work, If you are just checking noise. I think low even light would be the best since you are trying to make noise.


I think Jon's suggestion would work. But how are you going to quantify the noise. And would there be some ratio that one shows more noise than the other, for instance the 7D would have 1.6x the amount of noise of the 5D? Which I am sure will not be the case.


You and John are right- using the same lens and stopping down will work fine. Plus, if you only want to measure noise, it is better to use the same lens (I take back what I said about stopping down changing the transmission percentages: I thought about it some more and I think that using the same lens at different f stops will give very close light transmission rates)


Quantifying noise is tricky. The guys at dpreview tried it and failed, and came to the wrong conclusion that cameras with smaller pixels have more noise. I suspect that this is because they did something like "take a picture of a grey card and compute the standard deviation of the pixel values". The problem with this method is that vignetting will cause increased standard deviation (it is easy to correct for this- but it must be done)