CANON Obiective lens 28-80 for Projector

Hello everybody.
I wanna made my self-made projector.
My favorite's hobby is photography so i have many reflex and many obiective lens with many focal lenghts.
I wanna know if i can use one of they for the lens of projector..

in this case i can change the focus image and zoom while the projector is functionally.

Can i use ?!?! is it possible ?!?!?! if no why no ?!?!!?

Many link where i can buy a triplet lens for my projector ?!?!!

Greets.
simone
 
Hi simone,

I see some problems with your idea:
1. 35 mm lenses are made to cover, err, the 35 mm format, that is, 24 x 36 mm. Projecting the image of any LCD bigger than that will suffer from severe vignetting.
2. The focal plane distance of photografic lenses is usually too short to be used in a projector (for Canon lenses, IIRC, it' s about 46mm).
3. Heat! Photografic lenses are not made to withstand the huge amount of heat produced in a projector. Well, with some good fans...

Why not to use a good enlarger lens (for medium or large format)? They can be found quite cheap nowadays (thanks to His Uglyness digital photography, people are stopping using photographic enlargers...)

Cheers,

Bruno
 
projector parts

Process lenses are even better than enlarger lenses. If you use them for large format photography, then many of them can cover an 11" by 14" piece of film. So they work very well for big LCDs, ie. 15" or 17" diagonal.

If you want to make a projector using a smaller LCD (ie. 7"), then the optics are not so difficult to find. This is a good link, if you are in the EU:

http://www.exclusiv-online.com/shop/index.php?main=product&art=OSET1

They have everything you need, and you get a discount for buying it as a set.