While I was looking at the Sigma DP1 Merrill Studio Scene raw file, I decided to look at some raw histograms. This is the histogram of the whole image: It’s a 12-bit analog to digital converter (ADC). The putative blue channel (what I call the white channel in a Foveon sensor) has about 50,000 pixels… [Read More]
Archives for November 2023
More on Foveon image processing
I’ve never owned a Foveon camera, but I’ve owned many cameras that could capture 3 color channels at each pixel location. The cameras I’ve owned don’t produce images that look like a lot of Foveon camera images I’ve seen. I’ve been curious as to why, and have reported in this blog on some of the… [Read More]
Sample variation in the Fujifilm GF 100-200 at 200mm, revisited
A reader chided me for not using the same methodology when testing my copy of the Fujifilm GF 100-200 and another reader’s copy. To review, I tested my copy with a very complicated program that analyzes stacks of focus bracketed images, white balances the raw MTF curves, fits curves to critical measures, and calculates metrics… [Read More]
Where does the Foveon crunchiness come from?
Many people have noticed an artificial, unnatural “crunchiness” in images made with the Foveon sensor. Whether you think that’s a good thing or a bad thing is subjective. Many of the Foveonisti think it’s great. I think it’s ugly. Where does this wonderful — to some — or yucky — to others — characteristic come… [Read More]
Sample variation in the Fujifilm GF 100-200 at 200mm
When I measured the performance of the GF 100-200mm f/5.6 lens at 200 mm, I got good, but not great results. In fact, it was about the weakest performance I’ve seen with the excellent line of GF lenses. Ever since I published those results, people have been saying that their copy of the GF 100-200… [Read More]