A while back, I posted some examples of one-dimensional sampling and optimal reconstruction using sinusoidal signals. I’ve had some questions about other kinds of signals. In this post, I’ll look at targets that are similar to the USAF 1951 target, which has series of three black bars on a white background for various line spacings…. [Read More]
Fuji GFX 100RF shutter bokeh effects
Leaf shutter cameras have bokeh issues at high shutter speeds. A few months ago, I posted some really ugly examples from the Hasselblad 90mm f/2.5. We saw a bit of that with the GXF 100RF a few days ago when I posted the out of focus point spread function shots at 1/1000 second. Here are… [Read More]
ISO setting for raw files
I’ve taken a lot of shots at trying to explain the effect of ISO setting for raw files. Recently, I was asked to simplify my explanation. Here it is. Warning, some subtilties have been elided. I have likened the ISO dial to the little plastic steering wheel you stick to the dashboard so your 4… [Read More]
Nyquist and aliasing, with examples
Harry Nyquist was a Swedish-American engineer and physicist who spent much of his career at Bell Labs. In the 1920s and 30s he worked on telegraphy, feedback stability, and thermal noise, and in the process laid down results that became bedrock for how we think about sampling. His name is attached to a simple rule… [Read More]
Fuji GFX 100RF Siemens star testing, corrections defeated
Here are the same images as the preceeding post, but presented with Lightrooms profile correction and LaCA correction defeated. In the center: And in the corner: The lens corrections are lifting the corners and hiding the vignetting at f/4. This is a fine lens, considering its design emphasises… [Read More]