Recent content by cajer

What do you mean by diameter? Do you mean entrance pupil? According to the spec, the lens has an effective focal length of 27mm (not sure what they mean by effective focal length) with a 40 degree field of view (the sensor size is a 18mm diameter circle.). It appears that the older lens have...

I have an extremely fast (f/1.05) night vision optic that I scavenged from a old night vision unit which is faster than current production lenses (f/1.23). However due to the design of newer night vision tubes, the lens will not focus to infinity on the night vision tube. This is because the old...