Quote:
Originally Posted by Wavytone
Hi JA,
The reflections suggest it’s a singlet lens and the curvuature indicates quite a short focal length so for that aperture it’s not for forming a quality image.
Secondly the three screws have gears and the steep itch of the threads suggests they are for adjusting focus, not collimation - probably all three driven by a ring gear around the outside.
I’d guess it’s either a condenser lens, or a projector lens, possibly from:
A) spotlight used for illuminating actors on stage;
B) large overhead projector, of the kind used for displaying transparencies for lectures.
The latter were common in lecture theatres in the 70s and early 80s, and superseded by computer projectors and now large screens...
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Hey Wavy,
Or should I call you Sherlock, lol. What a fascinating insight into the possible origins of this lens. You obviously 'see' waaaay more than I do
