HISTORY:
Once, many moons ago, there was a stage lighting effects system from USA at the workshop, the technology (control electronics and use of incandescent light) was just too outdated to be pressed into service ... what to do? In the name of sustainability, the system was put on a trolley and taken to the "operating table" (workshop bench) and a few interesting bits and pieces extracted with a view to being used in "something" else ... like so many projects I dream up, that day never came so now this lens is looking for someone who may actually put it to good use.
There appears to be no special coating on the lens, it just passed light as part of a high powered stage lighting system. I don't believe it could be considered a "precision lens", just something that could be useful for experimentation.
UNKNOWN MANUFACTURER - Lens
Most likely it was manufactured in USA, everything else on the equipment was!
Lens type: Convex
Meaning that both sides of the lens are curved, the centre being much thicker than the edges.
The diameter of the lens at the edge is 4mm thick. The calipers on my micrometer would reach right into the centre of the lens but a pretty close thickness estimate in the centre of the convex side of the lens is 10~11mm.
Quite a heavy lens at 148g
There are NO mounting provisions, the edge is smooth and flat (as opposed to bevelled) and without any sort of anchor points. In the original equipment this was held in position with Silicon Rubber!
COSMETIC CONDITION:
That's all very well Russ (I hear you say) but what condition is the lens in? I took it out to the sunlight and viewed the lens at many different angles and cannot see any scratches or cloudiness. I have cleaned it with a soft cloth for optical use, with some lens cleaner.
I do see the very faintest of Silicon Rubber remnants at a couple of points near the outer rim, nothing towards the centre of course. These are very close to the outer edge and I couldn't imagine that they would affect light passing through the lens. I used ISO Alcohol to dissolve and remove the original Silicon rubber so if these marks bothered the new owner, a solution such as that will do the job but believe me these tiny marks are just that - tiny, and right near the rim edge, nowhere near the centre of the lens.
To maintain this condition, I have placed each lens separately within a cellowrap packet (I have been told that normal plastics can leave marks on glass) and then within a sealed clear plastic package, with the whole package secured in bubble-wrap.
