User talk:Lei-Fidelity

Yes, it's me, but I do not know how to get hold of you - pages with Lei-Fidelity do not exist. If you get this message, pls get back to my Talk page and tell me what you have in mind. I have not looked at the PH camera page in a long time.

Theopticist (talk) 21:56, 15 July 2021 (UTC)

I got your message. My German was once good enough for me and my dictionary to translate a monograph about Maksutov-Cassegrain telescopes, but that was long ago, so we will have to proceed in English.

I have not kept up for some time, but the paper by Young was one of the only attempts to measure the resolving power of the PH camera at different amounts of what he should have called defocus. There is no error - the x-axis is measured in units of s^2/lambda. In hindsight, it should have been obvious that the best focus is achieved when the image distance is s^2/lambda, because (as I noted in the discussion) that is when the pinhole is a Fresnel zone plate with 1 zone. The quarter-wave criterion and other estimates get close, but they are only rough guesses. The graph (which as you know, I put there myself) is experimental and therefore very important.

Regards,

Opticist

Theopticist (talk) 14:43, 16 July 2021 (UTC)