Originally Posted by ricwhite
Therefore, I believe what I read that even small amounts of light on the screen can ruin what would otherwise been a good high-contrasty image.
Thanks Ric. I agree that it definitely can. For me it is a difference between can and will though. If lights are pointed directly at the screen they can cause a lot of degradation, but there are many situations where LED lights do not have a direct path to the screen and the degradation can be very small.
I believe that a few things in articles out there are very misleading about how little light it takes and may have started with a guy in Australia who really never understood what he was talking about. For instance, how much the light from one candle will degrade things. I think somebody may have gotten confused about how much light there is from a standard candle and figured it would be 1 lux in a room when it is 1 lux 1 meter from the candle (and drops off from there).
I did experiments with a candle on top of a projector versus having a candle behind a chair in an off-white room along with a full 14" LCD worth of light when on a Windows desktop and pointed toward a side wall in a dark walled room and the amount of degradation off the screen can be more or less than people would predict based on many factors, like where the light is coming from and what paths it has to the screen.
A powerstrip with LEDs on it but placed behind a couch can be a pretty much non-factor in a light colored room with about 10k:1 on/off CR. I still generally cover my LEDs with neutral density material to be sure, but then there is some light, but way less than would be much of a factor even with 100k:1 on/off based on some testing I did where I simulated 100k:1 on/off CR using lower on/off CR projectors (because higher wasn't available) and neutral density filters.
I think it is also important for people to understand that a room can support super high on/off CRs (hundreds of thousands to 1+) even if it doesn't have dark walls.
I am hopeful that Epson can combine native on/off CR like the JVCs with a good dynamic iris and be able to push their multiplier beyond that 3x-4x that is generally the limit without causing more harm than good (other than the mostly useless trick of dimming down over close to 20 seconds on a black screen that Panasonic does basically to be able to claim a higher spec).
Of course, I've been waiting for a while for Epson to release their projector so we can see how they do with their relatively high native on/off CR combined with their iris.