Originally Posted by Thebes
nothing about a convergence setting by area (or more precise than one pixel by step) ? (like some Sony'projector)
As Mark wrote (sort of
) it reduces the visibility of color fringing from misalignment but it also degrades the picture in sharpness and color detail. I suspect you don't know how it works so you don't know why Mark wrote that. Here is some excerpts from my Sony VPL-VW60 review about how this type of Panel Alignment feature works. You can download the full review from the WSR subscriber's website.
"The VPL-VW60 has an innovative new feature that allows the user to adjust RGB image convergence in sub-pixel steps. All three-panel projectors are susceptible to convergence errors from panel misalignment. .... Manufacturers are striving to reduce the mounting tolerances but the convergence you get when buying a three-panel projector is mostly a matter of luck. Buyers sometimes feel like they are playing Russian roulette with a .44 Magnum. As Clint said in Dirty Harry (1971), “You've got to ask yourself one question: 'Do I feel lucky?' Well, do ya punk?”
Sony’s new Panel Alignment feature is designed to make you lucky. It is easy to electronically shift an image by single pixel increments on a projector’s red or blue display panels to improve convergence. Sony and other manufacturers have provided that feature on other products. But since panel misalignment is a mechanical tolerance the red and blue images really need to be shifted in sub-pixel increments to match the green image and fully correct convergence. Since the panel’s native pixels are fixed in place and can’t be moved electronically, Sony uses two native pixels to represent each adjusted pixel, and varies the brightness of the two pixels to make it appear as though the adjusted pixel is located between the native pixels. For instance, if the adjusted pixel needs to be half way between two native pixels, both of the native pixels are illuminated to the same brightness. By varying the brightness of two native pixels, the adjusted pixels appear to move between native pixels in 0.1 pixel increments. ...
Because single pixel blue and/or red lines are spread out across two pixels when the Panel Alignment feature is used some color fringing remains unless the image position is moved by exactly one or two pixels. However, the color fringing is much less than it would have been without correction since one of the two pixels will have much lower brightness than the unadjusted single pixel. The worse case occurs if you adjust the positioning by 0.5 pixel or 1.5 pixels since the two “new” pixels have equal brightness. I adjusted the red image by 0.2 pixels vertically to optimize convergence and the color fringing went from just noticeable at my normal viewing distance to not noticeable at all.
Most of our perception of sharpness and detail comes from the green image, which isn’t altered by the Panel Alignment function. But perceived sharpness and color detail may be reduced and that will vary based on whether you apply correction to both the red and blue images, whether you use both horizontal and vertical correction, and the precise amount of correction as discussed above. .... "