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I just bought this lens on Ebay. I have a 17" transparency with a 550mmand 220 mm fresnels. Looks to have promise.



http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...AMEWN%3AIT&rd=1

Close up. The 550 mm lens I got from 3Dlens was damaged when I got it so I cut it down to 10.2 by 13.6. So when it is framed it is a tad small.


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The 'S' is 3 mm tall on the transparency.

Throw is 115" and a 17" LCD would make a 76" screen.

You bought that eh? I almost bought it, but I decided the focal length was too long for me personally and my needs (I keep thinking short throw is better in my situation), congradulations. That looks good!

I haven't built a projector yet, but those verticle lines are they the circuliar fresnel grooves? If it is, it sure shows the need for fine grooves, what is the thickness per groove, is that .02 or .05? I forget the right decimal place, but you should be able to answer the question.

Err.. maybe that's just your screen material... oops.

The fresnel groves show because that is what he is focusing on or close to. I would assume he has the transparancy attached right to the (pressed up against) the fresnell. In a normal setup you leave a small gap , so that you dont focus on the ridges.

Nice find.

The lines are from the 220mm fresnel from diyprojectorcompany. Note that the 2 frenel lens are 10mm from my fake LCD. If the gap is bigger then the lines would not be seen. I put them this close because I cut my fresnels too small. Groove Pitch: 0.5 grooves/mm

I will be ordering new fresnels from Lumenlab as soon as they get some.
My new projector will be folded with a fs mirror.

rlwoodjr,

Thanks for the reply, I have one other question that I was always curious about. Two of my lenses that I am waiting to arrive are like yours, they have adjustable aperatures. What happens when you adjust from your F11 setting to your F40? Does the picture just get darker or does something else happen? Like corners cut off?

Just gets darker. The light stays even across the screen, it dims evenly.

How far away is the lens from the project screen? How big is the projection?

SCott

rlwoodjr,

Perfect answer, thanks.

Distance from wall is 115" and a 17" LCD would make a 76" screen.