Focus different in different areas of the screen?

[imdb_acc]

I noticed while adjusting the focus of my image that it is different in different parts ofthe screen. For example, if the corner area is in focus, the center is a bit hazy. If the center is made clear, the corner becomes a bit fuzzy. Is this for every projector?

[Trogdor2010]

It's likely the projector isn't centered to the screen, for fixed offset lenses, the projector is angled to a trapazoid shape (which requires keystoning, which does not fix focus issues), or lens shift is applied to a degree that covers an off focus centered part of the lens. The best way to mitigate this is to center the projector's lens (if you projector has a fixed offset, try to place the projector where the image is square). You should also check the condition of the lens, although that doesn't cause subtle changes to focus, you can tell if something is in the way. Some cases it could be the problem with the lens itself, which can be the fault by design, but higher end designs shouldn't have this problem.

[MrFattBill]

Originally Posted by imdb_acc

I noticed while adjusting the focus of my image that it is different in different parts ofthe screen. For example, if the corner area is in focus, the center is a bit hazy. If the center is made clear, the corner becomes a bit fuzzy. Is this for every projector?

Where are you in the zoom range? The closer to the middle the less likely this is to happen.

Bill

[drummerboy_2002]

Originally Posted by imdb_acc

I noticed while adjusting the focus of my image that it is different in different parts ofthe screen. For example, if the corner area is in focus, the center is a bit hazy. If the center is made clear, the corner becomes a bit fuzzy. Is this for every projector?

Yes it is. Why? You are using a flat screen, are you not? If so, the corners are farther away from the lens than the center is. The focus changes the focal length of the projected image. The further you move from the focal length, the blurrier the image will get.

[MrFattBill]

Originally Posted by imdb_acc

I currently have projector set on top of a table so I can't really adjust the height. Even though it is a trapezium, I haven't applied keystone correction. I haven't applied zoom either.
I'm trying to get maximum focus at the center of the screen. What do you guys do?

Which projector is it?

Bill

[MrFattBill]

Originally Posted by imdb_acc

It's an Optoma HD66. I don't notice the difference in degree of focus when I'm watching a movie but with the text of the desktop icons, I can clearly do so.

You have it at the correct off set from the bottom of the screen correct?

http://www.projectorcentral.com/Opto...ulator-pro.htm

Bill