I have found this image from my archives and wondering if there is anyway to estimate or calculate the exposure length of the photo?
The shot of of Orion (obviously) and my initial thoughts was to factor in the distance of the trail, measured against the known separation of the stars in the constellation. I've been trying to work it out but it's doing my head in
Before you ask, I do not know any info about the lens.
Can anyone help?
(ah, the days of long exposure film, no computers, no "stacking", no processing)