Originally Posted by jeahrens
Optics needed to properly resolve 4K are expensive. Whether it's included or added on (and a lens that does distortion correctly like an A-lens more so). While an A-lens does give more light we're still seeing output high enough to get good results on average screens. So, while an A-lens is still giving you an advantage, we're still at a point where lens memory has made the need for a custom panel largely irrelevant. As solid state light sources evolve, I would imagine the desire for $5K+ lenses will fall even more (though those that have one will still gain benefit).
You are correct the very nature of all projection is based around being highly inefficient going all the way back to the first film projectors. It is based around blocking light or filtering light, so the illumination source has to have a unit brightness for the highest brightness ever needed anywhere in the image at all times and then to make colors we remove what we don’t want and to make black we remove it all. All this energy being removed can only go one place and that is into heat. Not even to mention all the waste heat many of the brightest light sources make as a waste product.
HDR specs tell us it is imposable to do with projection so they resorted to tone mapping along with some extra brightness. HDR put an even higher demand on brightness that is mainly for highlights but nonetheless has to be there for the entire image and be blocked most of the time. Thus higher inefficiency when it comes to projection.
In contrast a light emitting screen like a flat panel display has its easiest task at making black not the hardest. All it has to do to make black is not turn that pixel on thus no power.
So yes to put a lens in front of the 4k projector to pass the image thru while compressing or stretching it has to be amazingly perfect and thus expensive. My suggestion is to not do the compression after the image is formed but to do it in the light path before the image to regain that 26% that eventually has to be blocked when doing the zoom method of scope presentation of CIH. These optics I don’t think would require the fine precision as if they were passing an image. Doing this would take away the light advantage of an A-lens method of doing scope and would then only leave the resolution advantage, and many people feel at 4k resolution that advantage is not as important as it was at lesser resolutions like 720 or 1080.
You are correct most of the new projectors do fine with brightness when as you put it use a average screen. But you have to admit with HDR who wouldn’t want an extra 26% brighter image or maybe support a 26% larger than average screen. That might mean for some the difference of being able to drop to an eco lamp mode and increase lamp life.
My point was with a device that is built around inefficiencies when there is an opportunity to improve efficiency for those doing CIH presentation why not explore it.
This concept would be of no use to me of course as I need that 26% brightness over the full screen area as I like to show IMAX movies that use that area that CIH zoomers never use but pay for.