Photographers often notice that objects near the edges of wide-angle images look stretched or distorted. A round object can look like an ellipse, and people standing near the sides of the frame can appear unnaturally wide. This effect is usually blamed on the lens, as if wide-angle optics inherently distort the world. What’s actually happening… [Read More]
Sharpness and aliasing, one more time
The question of whether aliasing counts as “fake sharpness” comes up regularly in discussions of camera resolution. In a recent post I summarized the difference between the GFX 50x and GFX 100x this way: “images are just as sharp, one has just more aliasing.” Someone objected that this must be logically flawed because aliasing creates… [Read More]
Using Curves adjustment layers in Photoshop
The Curves adjustment layer is one of Photoshop’s most powerful tools for shaping tone and contrast, and when combined with layer masks it becomes the digital equivalent of darkroom dodging and burning on steroids. Charlie Cramer, a fine-art landscape photographer and one of Ansel Adams’s former students, is perhaps the best-known modern practitioner of this… [Read More]
A pixel is not a little square, revisited
Just to be clear, the word pixel has several meanings. In this post, I’m referring to the value in the file, not the structure on the sensor. Alvy Ray Smith wrote a wonderful white paper when he was working for Microsoft. The title was “A pixel is not a little square.” I have referred people… [Read More]
Noise, Dynamic Range, and Print Size
Photographers talk a lot about noise and dynamic range, and camera makers are quick to publish specifications that promise ever-increasing performance. Those numbers are often reported at the sensor level: how many electrons a pixel can hold before clipping, or how many electrons of read noise lurk at the dark end. Those are useful engineering… [Read More]
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