Archives for September 2013

As we saw here, modeling the M240 as a normal camera with a slight negative offset helped explain the off noise floor characteristics, but didn’t provide a close match to the way the actual camera performs. It turns out that negative offsets can model the dark tone errors quite well. Here’s what the green channel… [Read More]

One thing to be ruled out on the M240 testing that I reported on here is that there might be something special about the green channel, where I got all my data. It’s a highly unlikely possibility, since the only thing that ought to be special about the green pixels is that they happen to… [Read More]

I performed the same test as I used in the last two posts on a Leica M9. Here are the results: The results, while not quite up to the exemplary standard set by the Nikon D4, are substantially better than the Leica M240 graphs. There is something strange, however. Like the M240, the M9 errors… [Read More]

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]