What are these lenses?

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I pulled out a light source and three lenses out of a slide projector. I have no idea what kind of lenses they are. Can anyone help me identify them? They are arranged in the order they were placed inside the projector.
 

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Hello

Trev, could that middle green piece of glass be IR absorbing glass? I’ve pulled a couple of slide projectors apart and they have got the same colour filter in them but placed directly in front of the lamp. So maybe they put it in the middle to get the right focal or some other reason.
This is only another possibility so don’t go spiten-th-dumb. 😀

DJ
 
Since I dont know much about lenses I will probably just use the pcx lens. Or should I use the pcx in combination with the dcv lens?

Hmm that depends on how wide the light from the condensers is and what size lcd your going to use, from my experience 2 condensers are always better then 1, they are much brighter and you have far less distortion in the image, but ofcourse thats only if you match up a pair correctly.

So in your case id see just how wide the beam of light is that comes from the condenser setup first, and from there determine if that light beam is wide enough to fit your lcd. Also i might add taking away the second condenser will change the focal length of the pcx lens and therfore it will change things in your design.

Trev
 
Trev, could that middle green piece of glass be IR absorbing glass? I’ve pulled a couple of slide projectors apart and they have got the same colour filter in them but placed directly in front of the lamp.

Its definatley UV filter bud, ir filter is pink, red, dark red, or orange depending on grade.

So maybe they put it in the middle to get the right focal or some other reason.

They more then likley placed it there so they use less of it and to use it as an optical spacer , though all lenses and filters shouldnt touch.

Trev
 
I think there's a bit of confusion over terms here.

No, none at all, the colour depends on the spectrum that is being blocked, also that filter shown in the drawing does not state that, that is the actual filter being sold.

Trust me, from first hand experience in purchasing the ir and uv filters , uv filters are clearly green to a blue colour, ( dependant of the spectrum being blocked), while all of the ir filters that ive owned that are of comercial quality designed for high light capacites are the red, orange, dark red, pink, and even purple colours.

Take a look also at cold mirrors, look through them at a 0deg angle (if you have a 45deg spec mirror), and you will clearly see a very dark red filtration, and a hint of purple.

Edmund Optics a major industrial optical manufacturer can clearly back me up with my claim.

Also i might add, optical filters for cameras are very weak and do not have the same qualities of the types of filters required for projection devices, that are powered with such high light outputs.

Trev
 
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