Just to make sure that there were no problems with my methodology, I reran the tests in the preceding post with a Nikon D4. The results: As expected. Each corrected data line is pretty much on top of the others. Here’s the closeup of the errors: Not only are the errors small, the direction is… [Read More]

I’m still trying to get a handle on the green shadows on pushed M240 images. I constructed a new experiment. I photographed this target: with the brightest patch about 3 stops down from full scale at ISO 3200. That gave me an exposure of f/11 at 1/60. I used a 135mm APO Telyt f/3.4 to… [Read More]

A photographer on a board that I read gave some anecdotal comparisons of the Nikon D4 and M240 as low light cameras. That prompted me to try to do some analytical comparisons of my own. It didn’t turn out to be all that simple. Stay with me and see. I thought to compare signal to… [Read More]

There have been a few requests for an explanation of the noise floor simulation in the previous post. Here it is. The program uses a model of a digital camera that’s illustrated below in one-pixel form: Light falls on the back-biased photodiode causing electrons to be released. The electrons charge the capacitor. The buffer amp… [Read More]