would this lens work or not?
fujinon 240mm f4.5
with a 2.5" lcd..
the calculator im using shows that at 78" i can only get aprox 20" picture.. but the calc is using fresnels and such and ive read for this small of an lcd i dont need to. am i correct on the 20" picture or will this be a good lens to use?
fujinon 240mm f4.5
with a 2.5" lcd..
the calculator im using shows that at 78" i can only get aprox 20" picture.. but the calc is using fresnels and such and ive read for this small of an lcd i dont need to. am i correct on the 20" picture or will this be a good lens to use?
not for an objective, it will give bad light and color abreviations, and bad edge or center focus. once again - I suggest a CRT lens.
I don't want to start a new thread for this and this seems to fit my question best.
Can this be useful in a diy projector?
http://www.tradera.com/auction/auction.asp?aid=9901463
If so, for what size of lcd? I'm planning to use a 11" one?
Can this be useful in a diy projector?
http://www.tradera.com/auction/auction.asp?aid=9901463
If so, for what size of lcd? I'm planning to use a 11" one?
lens
That 85 mm fl lens would be okay for a 2.5" LCD. For an 11" LCD, you need something in the 300 mm to 450 mm focal length range. It depends on what size image you want, and the throw distance from the lens to the screen.
An overhead projector triplet or duplet with a 325 mm fl would work pretty well: 92" diagonal image from 10 feet.
That 85 mm fl lens would be okay for a 2.5" LCD. For an 11" LCD, you need something in the 300 mm to 450 mm focal length range. It depends on what size image you want, and the throw distance from the lens to the screen.
An overhead projector triplet or duplet with a 325 mm fl would work pretty well: 92" diagonal image from 10 feet.
Right now i would like something around 50" from 7' distance because that is what my small room allows me to have.
50" from 7 feet
Then that would take a 386 mm fl projection lens. and somewhere around a 500 mm field fresnel. I don't know where you could find either of those. 325 mm lenses are cheap and easy to find. (61" image) 450-500 mm lenses are sold by some of the DIY projection sites. ( 36" to 41" image)
You could make your own 406 mm projection lens by putting a 1.25 Diopter reading glass lens at each end of a very short plastic tube. But maybe you should think about a compromise of the other dimensions.
Then that would take a 386 mm fl projection lens. and somewhere around a 500 mm field fresnel. I don't know where you could find either of those. 325 mm lenses are cheap and easy to find. (61" image) 450-500 mm lenses are sold by some of the DIY projection sites. ( 36" to 41" image)
You could make your own 406 mm projection lens by putting a 1.25 Diopter reading glass lens at each end of a very short plastic tube. But maybe you should think about a compromise of the other dimensions.
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