Can I use a projector at an angle?

map1984

Novice Member
I don't know if it's possible, but could I use a projector at 60 degree angle to the wall rather than the normal 90(without vastly reducing quality).
Thanks in advance, Mark.
 

kbfern

Distinguished Member
Not really, if the pj is not firing directly perpendicular you will have a trapezoid shaped image on screen. This can sometimes be corrected if off slightly by using keystone correction but this can affect image quality so best not used if at all possible.
 

Sandra51

Active Member
You could employ a series of mirrors set at the correct angle to bounce it around the room to get it square on to your screen but you would need a very small room as each bounce would increase the image size.
 

mb3195

Distinguished Member
What do you actually need to achieve? The projector will be needed to be pointed 90 degrees towards the viewing wall, but depending on which projector you have, you can then use lens shift to move the image quite substantially left, right, up and down.
 

noiseboy72

Distinguished Member
Most keystone correction that uses just optical correction is about 5 degrees. 60 degrees is very extreme and you will be using maximum correction to achieve this on even the more sophisticated units and you will be massively reducing the quality.

Can you supply a drawing of your proposed setup so that a more detailed suggestion can be supplied.
 

IWC Dopplel

Distinguished Member
Having spend some time setting my PJ up with laser measures, string and getting back into geometry it is quite difficult to align a PJ to be absolutely perpendicular to the screen. This keeps the focus correct across the screen. When this is done you can move the image left, right and up and down. If you fire at an angle to the screen only one 'bisection' will be in focus. I don't know what the depth of field (the amount deemed sufficiently in focus when moving front to back around the perfect line of focus) is on most PJ's. But.....
 

noiseboy72

Distinguished Member
Having spend some time setting my PJ up with laser measures, string and getting back into geometry it is quite difficult to align a PJ to be absolutely perpendicular to the screen. This keeps the focus correct across the screen. When this is done you can move the image left, right and up and down. If you fire at an angle to the screen only one 'bisection' will be in focus. I don't know what the depth of field (the amount deemed sufficiently in focus when moving front to back around the perfect line of focus) is on most PJ's. But.....
This depends very much on the lens throw. A short throw lens - 0.5-1.0 will have a quite a narrow focal range - possibly even struggling to maintain focus over the whole screen with some cheaper models, while a long throw lens can cope with more extreme angles and projector positions. For some live shows, we could be up to 20 degrees off axis onto 40' screens and could still deliver excellent image quality and some cinemas have less than optimal vertical angles due to the positioning of the projection booth.

The OP is talking about being 30 degrees off axis, which for a domestic projector is likely to cause resolution and focus issues. I think I would be looking at a better solution for this personally.
 

Joe Fernand

Distinguished Member
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