Originally Posted by Jack Ferry
Has anyone found any real world difference in offset compared to the calculated offset? For example, the Infocus projection calculator says that with my 96" screen and my ceiling mounted 4805 projector 14' back, there should be a 13.2" offset with the top of the screen 13.2" above the lens. However, in actual use, the top of my screen is 9" below the lens position - a difference of 22.2". And I'm not using any keystone, the image is perfectly rectangular, and the screen is not tilted. (Actually, I think the 4805 calculator on infocus's site may have the offset reversed.)
My question: Is the 18.7" offset calculated for the X10 with my screen size a valid calculation? Are you finding that the actual offset you are getting is the same as the calculated number? If it is off some, in what direction?
The two remaining barriers to me buying this are the offset and fan noise concerns. If those concern go away, it'll be time to box up the 4805 and move up to HD!
First, I'd have to make some assumptions about your situation. Looking at the numbers quoted above, it appears to me as if you have your image zoomed away from the default that they use in the calculator. If this is the case, you have to adjust the zoom factor on the projector calculator in order to get accurate numbers. That slider is on the left side of the calculator.
Then, it does appear as if they are showing an error in the picture where it shows the projector lens actually inline with the projected image. I don't know if thats the correct direction of the offset. You're trying to use a negative 9 and +13.2 as your differing values and unless that projector is different than it's brothers and sisters, that's not the case. If it's +9 and +13.2, a difference of 4.2", that could easily be caused by adjustment of the zoom.
I can say that the numbers quoted for the X10 are very close to reality. Way within the 4" error I think you are seeing, and way way within the 20+" if that is truly the case.
It sounds as if you have to just pretend that picture of the projector inline with the screen really means the projector is above the screen. Then it would all work out. Yes?
Look at the X10 calculator, that one shows the image correctly, below the inverted projector. I realize the numbers are not the same.