AVS Forum banner
1 - 5 of 5 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter · #1 ·
Hello, I just bought the Optoma GT1080 after my older projector died. Currently I have 3 options when it comes to focusing the image. Either the entire 1/4th of the bottom screen is blurry or The top Left and right corners are blurry or all the edges can be slightly blurry (gives about the same look at a 720p projector on the edges). The issue is not my screen. I confirmed this by 1. projecting directly onto the wall behind my screen and 2. My previous projector did not have this issue. Also the bottom center of the projection appears to be slightly lower than the sides.

I am not using any image shift or zoom. I do have a slight keystone added, but even when I set keystone to 0 the same areas are still blurry and everywhere else is sharp.
 

·
Registered
Joined
·
2 Posts
Discussion Starter · #2 ·
I'll correct that when I focus it so the bottom middle to look good the entire 1/4th of the left and right of the screen is blurry. So to make it clearer I'll restate the 3 looks my projector gives me

  • 1/4th bottom is blurry, rest is sharp
  • left and right 1/4th is blurry, rest is sharp
  • all the edges are slightly blurry
 

·
Registered
Joined
·
11,246 Posts
Short throw projectors can be very difficult to properly line up with the screen to produce perfect focus across the whole screen, and the GT1080 is a very short throw projector. The GT1080 must be absolutely at 90 degrees to whatever it's projecting onto and the surface it's projecting onto must be absolutely straight. Obviously you did not use any image shift or zoom because the GT1080 has neither. You should not have to use digital keystone correction either as long as the projector is aligned properly with the screen or wall that it's projecting onto and the screen or wall is perfectly straight.
 

·
Registered
Joined
·
132 Posts
Short throw projectors can be very difficult to properly line up with the screen to produce perfect focus across the whole screen, and the GT1080 is a very short throw projector. The GT1080 must be absolutely at 90 degrees to whatever it's projecting onto and the surface it's projecting onto must be absolutely straight. Obviously you did not use any image shift or zoom because the GT1080 has neither. You should not have to use digital keystone correction either as long as the projector is aligned properly with the screen or wall that it's projecting onto and the screen or wall is perfectly straight.
From the op's decription, its quite likely its a placement issue.

But, it might be a faulty unit too. For example, i recently went through 3 optoma hd142x, all of them had different focus problems and the pj placement was exactly the same. One was unusable due to uneven focus, either the right or left side was in focus. It was faulty without a doubt. The other two were fine but i could see see slight focus issues with them too. One had softer focus in bottom left, other one middle top compared to rest of the image. But i think they were within normal manufacturing tolerances. So, nashartwell, when you are sure you have the correct placement but find it impossible to get good focus, RMA it. Right now, seems like you are not using optimal placement based on the need to use keystone and bottom middle being lower than the sides.
 

·
Registered
Joined
·
7,207 Posts
You must place short throw projectors so that the image is completely square on screen.

I'm not sure what your old projector was, or if it was short throw like the GT1080. Standard throw and short throw are completely different beasts when it comes to setup, placement, and focus.

Once the image is square, you must be 100% sure that the surface you are projecting onto is perfectly flat. Typically, this can be seen by waves or distortion to the image.

Now, you can check for focus uniformity across the screen.

If the projector is tilted at all in relation to the screen surface, in any direction, then it will impact proper distance, which will impact focus.

All this said, you also have one of the cheapest projectors on the market, and expectations need to be kept in check against that budget.
 
1 - 5 of 5 Posts
Top