Click to view attachmentHi Ho folks. Being from Britain I wa unsure about buying anything from surplus shed, but I just ordered a projection lens to go with the PS1 screen I just bought and was wondering if anyone had any insights to how good it would be for that project.

I'm using a 120 watt floodlight for my light enging and i've tried that before with some nice bright results using a normal magnifying lens, so I figure with a real projection lens it should work better. I was using an old portable dvd player before but that didn't have av input so I was limited to movies, hence the use of the PS1 screen.

Here are the specs of the lens, and I have about 12 feet of room to play with so if anyone can give me an idea of what size of image to expect that would be great. (I know i won't get past 70-80 inches without some major screen door though). Thanks

Multi-element projection lens 210 mm f/4.7 ctd, 68 mm long 210 mm focal length.

Heres a pic

slipknot69,
Your lens should work just fine, i am using a 229mm FL copy lens, pretty similar to yours,
with 12 feet from lens to the screen(wall) you will get an 82" image but it will be pretty pixelated, you will need aprox' 222mm from the LCD to the Lens.
somebody please correct me if i am wrong, as i am still learning!

Hope this helps,

David Resnik

By no means take what I say here as absolute fact...

You want to match the focal length of the triplet to the field fresnel (or second fresnel). I think the idea is to use a fresnel that has a slightly longer FL than the triplet. So, to me, it sounds like you should plan to use a 220mm field fresnel. (So, you'll want to buy 2 220mm fresnels.)

Thanks for the insights guys. As I said Ive messed around with just an ordinary magnifier and got some half descent results but i want to do it right this time. This will be my 3rd shot at a descent project and I cant wait to get this lens. Ive got a good feeling about this one.

Thanks again

Slipknot

I wonder about this detail though "The middle of this assembly has a center stop making the center opening approx. 20mm diameter." (See view # 2 here) Doesn't that limit the field of view to 20cm? How large of a screen can such a small FOV handle?

Hmmm... that's interesting. I wonder if you would be able to take the lens apart (like the pro lens) and remove that stop?

Also, I see that the glass is only 45mm diameter, not 68mm like I thought...

Good news. I just got an email back from Surplus Shed saying "Looks like it would be no problem to take these apart. We only have a few left..." I was ordering some other stuff, so I picked up one to play around with. Anybody know about a calculator to determine needed FOV?

Now if only I could find someplace that sells small 220mm fresnels for cheap...