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]
Archives for February 2013
ETTR — just crank up the ISO? Part 5
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]
ETTR — just crank up the ISO? Part 4
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]
ETTR — just crank up the ISO? Part 3
Highlights are easy, you say, what about the shadows? I took a darkish area of the image, and applied a Draconian curve to it: ISO 3200, 0 EV push in Lightroom: ISO 1600, 1 EV push in Lightroom: ISO 800, 2 EV push in Lightroom: ISO 400, 3 EV push in Lightroom: ISO 200, 4… [Read More]
ETTR — just crank up the ISO? Part 2
SNR graphs are fine, but what does the preceding post mean with respect to image quality if I don’t push up the ISO to keep the histogram to the right? I wondered the same thing, so I did some testing. I took my usual noise test scene: And I made a series of exposures with… [Read More]