I’ve been working on improving the presentation of the SNR versus ISO setting data, and on improving the precision of the data itself. On the latter point, the most effective thing that I’ve done to remove systematic errors is to keep the shutter speeds constant throughout a series of exposures, and make all the required… [Read More]

I’ve been wrestling with some lack of repeatability in the measurements I’ve been reporting on in the last few posts. I haven’t completely solved the problem yet, but I thought I’d report on a series of measurements that I made yesterday. I worried that, because it looked like some of the SNR results might be… [Read More]

I looked at the SNR vs ISO/DIN performance of a couple of Sony cameras. How I made these curves is described here. As before, the way to use these curves is to find the ISO/DIN setting beyond which the Actual (red) line drops as fast as the 1.5 decibel/octave line. Beyond that point, for a… [Read More]

I’ve refined the calculations behind the graphs in the first post of this series. Specifically, I’ve added normalization to the 1.5 dB/octave lines so that they are corrected for the actual exposure of the test images, as measured by the mean value of the pixels in the selection box. The Poisson-limited lines had already been… [Read More]