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After hearing So many positives about the Nec lt150 (special thanks Huey) I'm pretty sure thats what im getting. I was just wondering how much i can adjust the keystone without affecting the picture I have a Vaulted celing so the projector will actually be about 9' in the air and i wanted to have the screen about 2' off the floor so thatwill put the pj about 8' back shooting down at an angle with about a 70" screen (I think) Thanks in advance for your time and input Wayne
 

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None.


Really all digital keystone adjustment has a detrimental effect on the image. Any keystone adjustment should be done by adjusting the screen or angle/position of the projector. However are you sure you need to adjust the keystone? Check the throw chart over at Nec's site - http://www.nectech.com/presentationp..._throw_v16.pdf
 

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The correct amount of digital keystone is always NONE. Not only does digital keystone reduce image resolution (it operates by blanking outer columns of pixels to return the image to approximately rectangular shape) but it also utilizes the internal projector scaling circuitry to operate. This makes it impossible to use the projector in it's highest image quality mode - Native Resolution, where you scale the signal externally in a HTPC or external scaler.


Gary
 

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I called NEC about ceiling mounting the LT150 and keystone correction.They suggested to stick to the chart as close as I could,the keystone would not allow for much correction.

I was looking to correct a 3 foot difference and the chart said 12 inches above top of screen to lens center.They said it would be best to stay with the chart.
 

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Of course dead-on projection with no keystone is the best, but in the real world the picture looks very good even with digital keystone adjustments (I've played around with mine).


It is something that you do want to experiment around with because, like horizontal pixel alignment (via tracking and phase controls) you can find "sweet spots" which can offer the least amount of distortion offering a reasonably sharp image.


-Dean.
 

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It is undeniable that digital keystoning affects the picture quality, but I wouldn't say that it necessarily "ruins" it.


I think that a pixel-matching scaler or HTPC makes a bigger picture improvement than the effect of digital keystoning creates with uneven pixels matching/alignment.


-Dean.
 
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