A reader asked the following: …did you find that AF focusing in the dark conditions with a nominal ISO locked @ ISO100 works worse than ISO for example being way higher ? Good question. Only one way to find out. Start with an a7RII and a Sony 90mm f/2.8 macro lens. Proceed as follows: RRS… [Read More]
Archives for September 2015
Sony a7RII zebras
There’s a maxim in medicine: “If you hear hoofbeats, think horses, not zebras.” It means look for the most common maladies first. I’ve always liked that rephrasing of Occam’s Razor. What’s that got to do with today’s topic, which is using the zebra viewfinder display option in the Sony alpha 7R Mark II (a7RII to… [Read More]
More on read noise and quantizing
A reader commented on the previous post: The real tough part of posterization is when a gradient is colored and you get hue shifts as the color channels step across bins individually. Can you redo this test with a color gradient, like maybe 0.6 0.8 1.0 relative values to the channels? Pleased to do so…. [Read More]
Read noise and quantizing, again
About a year ago I wrote a post on how read and quantizing noise interact in a digital camera. I concluded that, when the standard deviation of Gaussian read noise exceeded one-half the least-significant bit (LSB), the read noise provided sufficient dither that further increases in ADC precision would offer no increase in average digitizing… [Read More]
Cruising with the Sony a7RII – summary
The spirit may move me to comment on one or two narrow aspects of my photographic journey from Sitka to Seattle, but I think it’s time for me to summarize my experiences. If you want to start this report from the beginning, look here. A little context: as I said at the outset, I eliminated… [Read More]