Archives for 2013

With the self-heating tests out of the way, I could start to see the way that the noise floor varied with ISO setting in the D4. I set the shutter to 1/30 and made 16 exposures at ISO settings of 100 through 6400, selected 90% of the image area, and averages the statistics from each… [Read More]

I’ve spent a lot of time on signal-to-noise ratio (SNR) studies at mid and higher tones (Zones V through VII). Now it’s time to look at SNRs in the darker areas of the picture. Things get a bit more complicated as things get dimmer. At high photon counts, we can safely say that the mean… [Read More]

Here are the SNR graphs from yesterday, but for the D800E instead of the D4. There is even less reason to increase the ISO to improve the SNR of midtone and brighter values than there is on the D4. Note how low the statistical variation is compared to the D4. Why? I don’t know. Should… [Read More]

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]