Need help understanding lens shift-

[Dieselboy]

I'm trying to design (currently only in my head) the avaliable spots to postion a projector in my room and I'm a little confused as to what the 'parameters' are for where the projector can be postioned. How do I determine the maximum amount of 'off center' a projector can be mounted? Specifically I'm concered with how close I can mount it to the ceiling-

I'm going to mount it on a shelf built in the wall and I can go down a max of about 7inches below the ceiling. I know that LCD type projectors offer more mounting options than DLP, but I like the price of the HD20 Optoma. So when I go to projectorcentral.com and use their calculator for this projector it shows that at my throw distance of 13ft. there's a number of 8.6inches between the projector and the top of the screen- is this the minimum or maximum distance the projector should be mounted? Or does this number represent something different entirely?

[ditch-digger]

that means that the top of your screen will start 8.6" below your lens...

[Dieselboy]

So the DLP style is non-adjustable then?

[Trogdor2010]

The newer, more sophisticated projectors, including DLP use lens shift, but cheaper and early generation DLP sets do not feature lens shift, it is actually not recommended to use lens shift (heavily) due to light leakage and imbalanced color temperature, it is best to treat it as a convienience. You can position the projector to angle the projector (both on floor and ceiling mount if allowed, however you will have to risk keystone errors and using keystone correction will lose the 1:1 pixel relation in the 1080p display, this is not much noticable, but can present geometry errors if used improperly. For best results is to set the projector in the center and with little keystone correction as possible as none. Optoma's budget DLP projectors do not feature lens shift and the Mitsubishi 3800 DLP also does not. The cheapest 1080p projector with Lens shift is the Epson 8100 for $1600, or a used Sanyo PLV 700 if you can find one, these are also LCD projectors, and tend to not be as reliable as DLPs (from my experience), and need to be cleaned periodically.

[ditch-digger]

Originally Posted by Trogdor2010

The newer, more sophisticated projectors, including DLP use lens shift, but cheaper and early generation DLP sets do not feature lens shift, it is actually not recommended to use lens shift (heavily) due to light leakage and imbalanced color temperature, it is best to treat it as a convienience. You can position the projector to angle the projector (both on floor and ceiling mount if allowed, however you will have to risk keystone errors and using keystone correction will lose the 1:1 pixel relation in the 1080p display, this is not much noticable, but can present geometry errors if used improperly. For best results is to set the projector in the center and with little keystone correction as possible as none. Optoma's budget DLP projectors do not feature lens shift and the Mitsubishi 3800 DLP also does not. The cheapest 1080p projector with Lens shift is the Epson 8100 for $1600, or a used Sanyo PLV 700 if you can find one, these are also LCD projectors, and tend to not be as reliable as DLPs (from my experience), and need to be cleaned periodically.

lens shift does not produce light leak, its the input, and exhaust fan placement on the projector. lens shift on lcd do not degrade the picture. possible loss of lumens when zooming to much but thats it. as far as dlp lens shift, i have not seen them, and keystone is not recommended. lcd's are much more reliable in my experience than dlps. the bulbs, are not as long lasting, and the pj shells are much much smaller and cant disperse the heat properly lending to overheating, and malfunctions. and lcd can be placed almost anywhere in the general area of the screen, with no loss of quality, and dlp's tend to give a good percent of people rainbow effect while watching..

basically if you cant get a great deal on a lcd 1080p then go with a very good 720p lcd. there is a reason why the dlp's 1080p's are so inexpensive. if not sure i highly suggest calling projector people. they are some of the most knowledgeable people i have spoke to. they have seen every pj out there, and test them all. i guarantee they will get on the phone and tell you the same thing. one sales rep told me they (all) choose the top lcd 720p models over the $999 1080p dlp's. its not all resolution..look up the

http://www.projectorpeople.com/proje...ome+Cinema+720

http://www.projectorpeople.com/proje...onic+PT-AX200U

just because something is cheap does not mean you should get it...