Discussion in 'Projectors, Screens & Video Processors' started by buns, Sep 14, 2003.
ask me at AV talk
From what I gather if the panel is 4:3 and you project a widescreen image you'll be wasting horizontol resoultion of the panel. Just like a 4:3 TV, they'll be more unused space, therefore lower picture quality. Rather than a widescreen panel, and using more of the panel.
Don't know anything about lenses though.
the point of the lens is you leave the picture on the 4:3 panel compressed (ie dont use anamorphic mode) and the lens does the stretch..... hence no loss of pixels on the panel. I just dont know how the panels match up.... since 4:3 is more common, are the panels of better quality leading to a better overall performance of projector? Or are the 16:9 panel machines just as good?
I htink you mean vertical resolution (horizontal lines).
The whole point of the anamorphic lens is to distort the image back in to the correct aspect ration allowing you to use the full resolution of the panel. This is what they do with D-Cinema.
You would still set your DVD player or STB to 16:9 and the image on the face of the PJ would be tall and thin. It would be squashed OPTICALLY.
BUNS: From what I have seen of such lenses they can cause pincushion distrotion unless specifically designed for your device. Also good ones might well cost more than your PJ....
Ah right so optical squashing is better (if the lens is perfect, and price is a non-issue)- rather than electronic squashing.
However I take it it's still better if the panel is widescreen shaped, and the lens is just a normal type? Surely using more pixels on a widescreen LCD panel is better than using a 4:3 panel, with unused pixels just projecting black?
The difficulty I forsee, is that, quality of the lens issues aside, in order to properly watch a source that is not 16x9-shaped, you would have to physically remove the anamorphic lens and refocus the projector. This sounds like a bit of a 'pain'. Also, for the (now relatively few, thankfully) movies letterboxed into 4x3, you either need to also operate the optical zoom on the PJ, or end up watching a smaller image area. Better, IMO to use a 16x9 panel, and then only use a part of it's pixels, when a true 4x3 image is being displayed.
BTW, Gordon, why do you suppose its is that you (and many others, including me) have a tendency to spell 'ratio' as ration?
Nathan - assuming the DVD is producing a full-screen 16x9 image; if you were to watch such a signal on a 4x3 device, it would fill the screen, but everything would be the wrong shape. On an LCD (etc) all the pixels would be in use. The proposal here is to take exactly such a setup and then optically distort the image back up to its correct width. All the pixels remain in use.
Good grief! ration indeed. I have no idea. I re-read what I typed before hitting send and never noticed that. I rememebr seeing an email a year or so ago that had a paragraph of text in it. You had to read it and write down how many "F"'s were used I think. I read and re-read and still got it wrong. By miles! It was some psychological test I think. Amazed me.
thanks guys..... the thinking i have is that an sxga 4:3 panel costs less than the equivalent wsxga.... or whatever res you happen to be talking about..... so by using 4:3 panel and lens..... you can get the resolution of a more expensive widescreen panel..... if you see what i mean. Of course the difference may be negated by lens cost.... only ref i have is avs selling a used scoped lens for $400 so id assume new would be $600 ish.
Yeah there are potential issues when using material not matched to the lens..... with a 16:9 lens this is ok..... i dont in fact have any non 16:9 material, so it wouldnt be an issue. Fair enough with a scoped lens id have to do some fiddling, for a non scoped picture i would be forced to have myself a rather funny powerstrip res (id have to artificially compress in the horizonal) but it would work.
Am i to assume that 4:3 projectors and 16:9 offer very similar performance at the lower end of the market...... this i suppose is what i should have asked in the first place!
ps. why dont we see more made of the lens used on projectors..... anytime we use a lens in the lab it is a real bugger to get one that is any good, surely in a projector the quality of the lens is a big factor in performance?
I have often wondered why....... for example, when DLP chips first came out - inevitably they were all 4x3 jobs - 16x9s are only recently beinning to appear.....Home Theatre projector manufacturers didn't consider using anamorphic optics to get over the issue. Given appropriate scaling in the projector (or outside even), a 4x3 image could be rescaled to fit 16x9, displayed on a 4x3 panel (laterally compressed) and then resired with a suitable lens. But nobody ever did this commercially....AFAIK. Would have avoided the need for Texas to produce different DLPs for presentation vs. movie purposes.
it is an interesting point..... but it is a bit of a spin on normal convention..... why make a simple change on an established line when you can start all over again!?
Prismasonic sell these lens' which are very similar in design to the Panamorph lens, but much cheaper. Someone on the forum bought one and had favourable results with it IIRC.
The other advantage of using an anamorphic lens, especialy with LCD projectors, is the reduced screen door effect.
If you can hide any distortion, then the 4:3/lens combination would probably be the better solution I would think. However, just to add to what Gordon said - sometimes these lenses will only work with the projector zoomed in to produce it's smallest image, otherwise you get distortion. This may mean moving the projector back quite a bit. I think that was the case with the HT1000.
I read on avs that folks r using these lenses on 16x9 panels to create the super wide ratios as in the cinemas (cinemascope), pictures of it looked fantastic.
Cant remember what the thread title was though.
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