The way I understand it...
Using a standard 80mm triplet will give you an image that is to large to put the projector behind the view without the viewer being right up on the screen. A long throw lens will allow the projector to sit much further back for the same image size. However it seems like folks are having problems using say a 135 mm long throw triplet with 15" or greater sized LCDs.
Instead of trying to use a long throw lens... why not just use the 80mm lens, and sit the projector on the floor/ceiling, closer to the screen, tilt it, and use the front fresnel to adjust for keystone?
Using a standard 80mm triplet will give you an image that is to large to put the projector behind the view without the viewer being right up on the screen. A long throw lens will allow the projector to sit much further back for the same image size. However it seems like folks are having problems using say a 135 mm long throw triplet with 15" or greater sized LCDs.
Instead of trying to use a long throw lens... why not just use the 80mm lens, and sit the projector on the floor/ceiling, closer to the screen, tilt it, and use the front fresnel to adjust for keystone?
>> Unless the loss of sharpness through the fresnel lens bothers you.
So in otherwords tilting the front fresnel will cause a loss of sharpness?
So in otherwords tilting the front fresnel will cause a loss of sharpness?
You're putting the fresnel lens in the image path, they are usually intended for concentrating a light source rather than sitting between the image source and projection optics. You will see some amount of blurring.
However: this might not bother you. In fact, some people intentionally defocus their projectors a tiny amount, because they find the sharp edges of pixels (screendoor effect) can be distracting. My preference is sharp pixel edges, especially for computer use rather than video playback.
However: this might not bother you. In fact, some people intentionally defocus their projectors a tiny amount, because they find the sharp edges of pixels (screendoor effect) can be distracting. My preference is sharp pixel edges, especially for computer use rather than video playback.
With my current split design... I see very sharp pixel edges. Ive never tried an unsplit design though...
>> It looks stupid, especially with a ceiling-mounted projector.
I think if the screen is framed well, you could tilt the screen a few degrees either way and you wouldnt be able to tell.
I think if the screen is framed well, you could tilt the screen a few degrees either way and you wouldnt be able to tell.
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