Measuring read noise is useful, but by the time the image is so dark that you can see the read noise, the photon noise is usually pretty bad. For me, the photon noise is usually more important as a measure of practical image quality. I did a variant of my usual test that shows the combined… [Read More]

Like most cameras I’ve used, the D810 has an option to have the camera do processing to remove noise a for long exposures. Like most people I know, I leave if off most of the time. I made a series of dark-field exposures with and without the long-exposure noise reduction: Not what I expected. First… [Read More]

I brought the dark-field exposures of the previous post — plus a few more so that I has an exposure every 1/3 stop — into RawDigger, selected the central 90% of the frame, and measured the standard deviation of the read noise. I normalized the results to a full scale count of 16383, and here’s the… [Read More]

Before I start seriously testing a camera, I make a series of dark field exposures to see if there are self-heating effects that would compromise results made with rapid series of shutter activations. Of late, it’s not been a problem. Here’s the standard deviation of each raw channel for a series of exposures of a… [Read More]