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]
ETTR — just crank up the ISO? Not so fast.
When I was in college, I learned a colloquial formulation of the laws of thermodynamics: The first law of thermodynamics says you can’t get something for nothing; the second law says you can’t even break even. Exposure in digital photography is a little like that. I’ve been talking about ETTR for a while now. You… [Read More]
Scheimpflug for dummies
In making the test images for the previous post, I reacquainted myself with the frustrations of using live view in its present incarnation to adjust tilt angle and focus. What I really want is to be able to see magnified views of two portions of the image of my choosing simultaneously, so I can see… [Read More]
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