AVS Forum Special Member
Join Date: Aug 2005
Location: Brisbane, Australia
Mentioned: 9 Post(s)
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I know of the post your referring to as I could not find it either.
If you can connect a PC to your projector, make yourself a single pixel line pattern using paint (set the pixel count to 1920 x 1080) and display it 1:1 on your projector. You can add as many focus and geometry points as you like. The key thing being that when the astigmatism adjustment is correct, both the horizontal and vertical lines will be the same intensity and sharpness and your image will as sharp corner to corner.
Once your lens is mounted correctly:
1. Start with the lens out of the light path, and focus the image as good as the projector's optics will allow.
2. Move the lens into the light path and observe any changes (apart from width) the lens has made.
3. Rock the front portion of the lens (rubber rings) to bring both the H and V lines into focus at the same time. There is no right or wrong final position here as this is based on TR and how the optics focus at the specific distance your projector/lens is away from the screen.
I seem to remember something in the post about "rocking the projector's focus" during this adjustment. I'm sure the original poster stated their reason for this, however I don't do this when aligning my lens. Simply put, if you follow the 3 steps above, the image is sharp with out the lens, so making the astigmatism adjustment should only be used to bring the image back to corner to corner focus as adding the anamorphic lens to the light path is the only change you have made. If you move the lens out of the light path (as many do for 16:9), then you don't want to have to touch the focus of the projector once everything is dialed in.
Hope that helps.
I love my Constant Image Height system!