A few posts ago, I showed you the results of running slanted-edge modulation transfer function tests on the Sony a7 and a7R, both handheld. Since the cameras have different resolution, and the test results for MTF50 were in terms of cycles/pixel, I multiplied the a7R values by 1.22 so that the MTF50 results were in… [Read More]

Actually, this post applies to MTF analysis in general, whether the camera is on a tripod or not. In the previous post, I said: to get the system’s modulation transfer function (MTF), we perform a Fourier transform on the system’s impulse response, or point-spread function (PSF), and throw away the imaginary part. What do we… [Read More]

A reader has asked if I could take the methods that I developed for the handheld testing and apply them to tripod-mounted testing. The MTF-based technique offers the ability to test more conditions because of its automation, and provides objective, machine-generated results. However, the old procedure, with its visual analysis of ISO 12233 images, is… [Read More]

I think I have very-late-onset dyslexia. I reported yesterday on handholding tests with the Nikon 58mm f/1.4. The graphs were actually of the second set of tests I attempted. When I did the first ones, this was the result: Very strange, I thought. The electronic flash resolution was much lower than I thought it would… [Read More]