Hey Im Dustan and i accedently Threw a Knife into my 54 inche tv... but no worries! cause i took it apart, rebuilt it and now its a pretty grand projecter. but thing is... that i need help. first of all i need to be able to focus it. like the picture is ALWAYS focused but i mean like, The tv needs to be very close to the wall to cover the wall, so that i cant have a couch or anything. is there anyway to Decrese the size of the projection so i can move the tv backwards?

also if i use any sort of mirrors to help i need to keystone and i have no idea how to do that with this type of system

Thank you so much for any help

To focus a given lens assembly, you need to vary the distance from the image source to the lens.

In order to focus a picture farther away, the lens needs to be closer to the image source. This ALSO increases the magnification of the image. Even if it didn't it would increase the overall size of the image as well. It's a double-whammy.

There is a hard limit as to how close a given lens can be to the image, which is hte FL of the lens itself. Once you get to this point, the image will never come into focus at any distance.

In order to decrease the size of the projection, you need a longer FL lens.

Your first step, therefore, is to determine the FL of the lens that you have, then determine the FL of the lens that you NEED. Once you have that, then you want to figure out if you can USE the lens that you need. It's no good if the light trough your image source (typically LCD) can't be directed to a further point for the lens that will give you the throw that you want.

Really, I'd start looking for a replacement rear projection screen, and fix the TV you have.