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I assume you mean that zooming seems to alter the perceived brightness value. It shouldn't actually affect any real brightness settings in the projector.
Since all of the optics involved at different zoom levels are the same, there is no actual change in the total amount of light from the projector to the screen. However, as the actual projected image itself gets larger and smaller, you definitely will see a change in the image brightness, simply because there is a change in the total amount of light available divided by the number of square inches of image. This is essentially the benefit of using the panamorph lens to view 16:9 images with a 4:3 panel.
As far as where to mount your projector, I would install it such that the largest image (zoomed out?) produced is just a little bit larger than your desired screen size. This will give the most amount of "useable" zoom. You may find that you'll want to zoom-in when viewing poorer quality signals (VCR, NTSC).
Technically speaking, the measured light intensity drops off at an exponential rate in relation to the distance. In other words, the closer to the screen, the better.
| Originally posted by sprakash Also, would the brightness be affected since while using dilard, the degree of zooming seems to alter the brightness values. Thanks in advance, Sanjiv |
Since all of the optics involved at different zoom levels are the same, there is no actual change in the total amount of light from the projector to the screen. However, as the actual projected image itself gets larger and smaller, you definitely will see a change in the image brightness, simply because there is a change in the total amount of light available divided by the number of square inches of image. This is essentially the benefit of using the panamorph lens to view 16:9 images with a 4:3 panel.
As far as where to mount your projector, I would install it such that the largest image (zoomed out?) produced is just a little bit larger than your desired screen size. This will give the most amount of "useable" zoom. You may find that you'll want to zoom-in when viewing poorer quality signals (VCR, NTSC).
Technically speaking, the measured light intensity drops off at an exponential rate in relation to the distance. In other words, the closer to the screen, the better.
