squirrel$$$bandit
Veteran
This seems too good to be true:
http://www.amazon.com/RainbowImagin...1?s=electronics&ie=UTF8&qid=1310911835&sr=1-1
How is it even possible? Has anyone used it?
http://www.amazon.com/RainbowImagin...1?s=electronics&ie=UTF8&qid=1310911835&sr=1-1
How is it even possible? Has anyone used it?
Pherdinand
the snow must go on
haha! we built thses things in the optics lab and used it for class 4 lasers.
not sure though what's the truth behind "wide band".
I expect it works as a double polarizer (that's how we did it). The idea is, you use a polarizer to polarize the incident light and you use a second polarizer to cut out power.
The first polarizer, say oriented horizontally with its polarization axis, transmits the horizontal polarized component of the light. The second one can be oriented parallel with first (=highest transmission), 90 degrees crossed with it (=strongest ND filter) or anything in between.
In practice, it's probably the first one that can be rotated not the second one (makes no difference) and there should be some quarter-lambda plate in front that circularly polarizes the incident light in order to make sure the whole thing does not act as a polarizer but only as a ND filter).
For truly wide band and 1 to 400 ND this must be made of some sort of polymer otherwise it would be extremely expensive. Not sure what that will do optically to the lens properties.
EDIT: 2 to 400 ND, of course. not 1 to 400, coz ND1 means zero power loss.
not sure though what's the truth behind "wide band".
I expect it works as a double polarizer (that's how we did it). The idea is, you use a polarizer to polarize the incident light and you use a second polarizer to cut out power.
The first polarizer, say oriented horizontally with its polarization axis, transmits the horizontal polarized component of the light. The second one can be oriented parallel with first (=highest transmission), 90 degrees crossed with it (=strongest ND filter) or anything in between.
In practice, it's probably the first one that can be rotated not the second one (makes no difference) and there should be some quarter-lambda plate in front that circularly polarizes the incident light in order to make sure the whole thing does not act as a polarizer but only as a ND filter).
For truly wide band and 1 to 400 ND this must be made of some sort of polymer otherwise it would be extremely expensive. Not sure what that will do optically to the lens properties.
EDIT: 2 to 400 ND, of course. not 1 to 400, coz ND1 means zero power loss.
squirrel$$$bandit
Veteran
A little research proves you right--it's a double polarizer. Supposedly multi-coated glass, FWIW. Interesting.
Rob-F
Likes Leicas
I bought an inexpensive Leica to Nikon adapter from Rainbow Imaging and it worked fine.