I'm ready to buy within 30 days and have been looking at the RS1 vs. the VW50 and there's something that doesn't make sense to me. On Projector Central, the VW50 is listed as 900 ANSI lumens while the RS1 is only 700. When I put in identical parameters into the throw distance calculator (100" diagonal from 15' back for example), the VW50 image brightness is listed at 8fL (and flagged as too low) while the RS1 at the same distance is listed at 13fL. In fact, the Sony is flagged as "Recommend higher brightness" with a 100" diagonal regardless of PJ position/zoom. How is a PJ with 200 fewer ANSI lumens able to apparently achieve a 50+% brighter image?

I'd appreciate some insight into this. The VW50 (or 60 now) looks appealing, but I don't want to end up disappointed in the image brightness.

Thanks in advance!

Should be noted that the 700 lumens for the JVC would be a something close to shortest throw. It drops somewhat at farthest throw, although with a gain in contrast.

BB

Reito is full of bitterness about marketing. He is not using his brain.
Most projectors lose brightness as the throw distance increases for any given screen size. This is because most zoom lenses are not constant aperture but decrease markedly in effective aperture as you zoom out. In this case your screen width is 87 and your throw is 180 inches, so your throw is a little over 2.0. The Sony throw range is 1.41 to 2.40, with a non linear (actually its exponential) loss as you leave the closest throw and move to long zoom. At 2.0 you will have lost about 30% of the light from the closest throw.

ANSI lumens are measured as a max. Closest throw, IRE 100, new bulb, open iris. Often the color temperature will be set higher than D65 too because that will increase the lumens. In this case, you will after bulb aging end up with an average illumination on the screen of say 250 lumens. Your screen is about 30 sq ft, so if you divide 250 by 30, you will get a litle over 8 ft lamberts. This is a guess because of my assumption of average viewing scene after bulb aging. If you add screen gain, going say from a 1.0 gain to a 1.3 gain screen, you will get say 10.5 ft lambers. Recomended is 10 to 12 ft lamberts for a movie theater. Shorten your throw distance to 11 ft and you will have plenty of light just as you will at 15 ft until your bulb ages.

From my extensive testing on RS1's, I have found they ranging anywhere from 450ish to over 700 at the short throw, depending on the lamp mode. Published specs are a best case scenario typically.

On some units (especially common on presentation products) they often are not rated at D65 so the end number is a bit higher than they will end up after calibration.

Thanks for all the info - this is very interesting stuff. Something still doesn't add up for me though. The lumens listed for the 2 PJs on the projectorcentral calculator match the "official" specs from Sony & JVC, so I assume that the calculator takes them at their word and isn't adjusting the Sony's light output down because the official spec is unrealistic. Given that, how is it that a projector with (supposedly) fewer lumens projects a brighter image from a given distance than one with (supposedly) more? Isn't the image brightness just a function of light output, zoom, distance, and screen size (again taking the mfr's specs as gospel as the calculator seems to)?

My buying decision hinges on this. If the Sony's brightness would work for my room, I'll watch for impressions of the 60 to trickle in and most likely go that way, but if it won't, I'll pick up an RS1 immediately for my HT that will be ready in the next 2 weeks.

I cannot comment on ProjectorCentral other than I cannot tell you how many times they're calculator has been inaccurate (all their calculators). I have had many customers come to me to buy a projector that they prewired based on PC's chart, and then found that it was wrong, thus causing them to have to either move it or change projectors last minute. Take it all with a grain of salt.

Derrek. Trust Jason and myself on this one. We agree. We both sell and install these things to supplement our welfare payments.