Originally Posted by mblank
Xenon? But Pearl is UHP.
And don't you mean it loses brightness at minimum zoom? The CineHome measurements, btw, were closer to 15% loss at minimum zoom...
Yes the pearl is UHP. That's why I said even without ... Xenon
i.e. that even though it does not have the (debatably) rapid dropoff of the Ruby it will still lose ~50% of it's initial brightness like all UHP bulbs do. UHP has a reasonable dropoff after the first 10% of its life and then a more gradual continuous drop in light output for the rest of the bulb life.
Minimum zoom = shortest throw.
I just read the cine4home article, and although it mentions that it uses the same zoom lens as the Ruby (which I would assume would cause the same light dropoff characteristics) he mentions a 17% dropoff in light but doesnt mention at what zoom extents (i.e. whether that dropoff is going from minimum to maximum zoom or not.)
If it is from min to max zoom, then that is an improvement over the Ruby.
Using the measured cine4home numbers, in the best case, you can get an initial 700 lumens @ D65, min zoom, adaptive iris, bulb in high mode, ~10000:1 DI CR. Given usual UHP bulb behaviour, this will likely drop to 350 lumens after a while (still bright enough for many uses). This is the brightest case. You can do the math on the other quoted values in the table. You could choose your screen where 700 lumens are just bright enough to give you the brightness you want, but then for the majority of the life of each bulb, you will be living with a brightness level significantly below that initial value. This is true for all pjs, nothing specific to the Pearl. You are better off chosing screen material and size based on the 50% number, IMO, but to each their own - not looking to offend anyone here.