ANSI Lumens / Projector Calculator / Illogical Foot Lambert Readings

Mark (Basspig) Weiss

Well-Known Member
Aug 3, 2010
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I'm reading specs on various projectors and checking the predicted brightness on Projectorcentral.com's calculator.

The problem is that higher lumens-rated projectors are coming back with much lower FL ratings on the calculator, for the same size screen, which defies logic. Brighter projector should equal brighter FL on a screen with a given image size.

I compared a bunch of projectors based on 60" image height.

My existing InFocus IN82 comes out to 34FL on this calculator. The projector is rated for 1500 lumens.

Infocus has a newer model out called the IN8606HD, which claims to be 2500 lumens. However, throwing the same 60" height image, the calculator says only 28FL. My suspicion led me to check the bulb technology and wattage. It's also a UHP mercury arc lamp, like the IN82, but the wattage is much lower, at 220 watts, vs. 300 watts for the IN82. So either the industry believes in unicorns (that somehow a 220W lamp is brighter than a 300W lamp), or the projector calculator is giving bogus results.

Presently, my IN82 is only 14' from the screen, so the largest image I can get is 45" high (and at that dimension, approx 92" diag, the brightness comes to 60FL). It's at a comfortable brightness, about like an LCD TV, but much larger, but the problem is that I have 1/3 of my 154" 2.35:1 screen unused. The IN8606HD has a shorter throw angle, and would fill my screen top to bottom from the present mounting position. I was hoping the extra 1000 lumens would make up for the larger area, but the calculations at Projectorcentral tell me it's not even as bright as my current setup, even for the same image size.

What's going on here? Have the ANSI standards changed since 2009? Are lamps of the same brightness being assigned higher lumens ratings? Or is the data for many projectors incorrect at the calculator, thus rendering artificially low FL numbers? I don't want to even consider changing out my projector if it's going to be a step down in brightness (and a much bigger step down if the image size goes up). Short of hitting the lottery and buying one of those 40,000 lumen commercial projectors, what are the options for finding the honest screen brightness? People tell me my current setup is "blindingly bright" (that was an exact quote from one of six people who attended a screening of "The Wind Rises" that I showed here last month. I rather like it though, because my fireworks video looks more like fireworks.

Another thing that concerns me are with projectors like the BenQ 1070, they claim 2000 ANSI lumens and reviewers talk about how bright it is, but say the contrast and black levels aren't that great. I'm quite happy with the black levels and shadow detail on the IN82. If I were to nitpick, I'd want more gamut in into the reds. Mercury arc is weak on red light output. But to overcome that would require LED or Laser technology. I just want the image to be bigger without having to knock out another support column to move the projector back another two feet. The IN8606HD looks tempting at $799, which is cheap compared to the $5200 MSRP of the IN82 that I bought used for $1400 in 2009, but if they're lying about the lumens (and it seems they are contradicting the laws of physics to claim a lower wattage bulb of the same tech is brighter than a higher wattage bulb) I don't want to waste my money.

My manual calculations say that the 2500 lumen projector on my 60" image height (16:9 aspect means 8.8' wide, thus 44 sq ft area), so 2500 lumens / 44 sq ft = 56 FL. Not 28 FL.

Maybe someone here with some insider info can relate what's really going on with ratings and why the brighter projectors are so dim in the calculator results.
 

JackD201

WBF Founding Member
Apr 20, 2010
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Could the calculator itself be programmed incorrectly?
 

Mark (Basspig) Weiss

Well-Known Member
Aug 3, 2010
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Could the calculator itself be programmed incorrectly?

I don't think so. It's correct with the IN82 parameters. It's the other models that are returning abnormally low FL numbers.
The calculator is a major one at projectorcentral.com.

What I'm starting to suspect is that the other projectors are using the 'text/presentation graphics' setting for their lumens ratings, rather than 'games/movies' mode. If I switch the calculator to that mode for the BenQ, I get something closer to 40 FL. So perhaps several of these 'high output' projectors are actually dimmer than the IN82, which is a movie projector. Maybe the 2000 lumen projector is that only in text/graphics mode, but drops to 800 lumens in movie mode. Funny thing is, if I select 'text/graphics' for the IN82, I get 120 FL and the IN82 has no such mode!
 

JackD201

WBF Founding Member
Apr 20, 2010
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Interesting!
 

Mark (Basspig) Weiss

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Aug 3, 2010
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Got a reply from Projector Central staff this morning. This clears up the mystery and it's a matter of dishonesty on the part of the manufacturers to advertise text/presentation mode lumens on a home theater PJ:

"The calculator makes some assumptions that you may not be following. It will reduce estimated light output for video modes on some home theater projectors but not others based on whether the lumen ratings published by the vendor are video optimized or not. Also, projectors load into the calculator in a default operating mode based on their anticipated common usage--presentation vs. video. You might not notice that change when switching between models. It also makes corrections based on the position of the zoom lens--the farther toward telephoto a zoom is, the dimmer the projector gets. So it is often true that a projector's rated lumen output will not correspond to the fL numbers reported by the calculator."

It may well be that the IN82 was one of the brightest projectors under $10K. Not many PJs today have a 300 W arc lamp in them. Most are 2/3 that and cheat by using white segmented color wheels. Also noticed the lenses on newer PJs are much smaller. Mine is huge, like an old broadcast TV camera lens. The new PJs have lens only a couple inches in diameter. That cuts down on the the light transmission too. Seems like projectors are taking a step backwards in brightness lately. Green, energy saving strategy?
 

JackD201

WBF Founding Member
Apr 20, 2010
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Manila, Philippines
That or lamp cost saving strategy.
 

GaryProtein

VIP/Donor
Jul 25, 2012
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Mark, do a google search for --- "delivered lumens" vs "source lumens" --- it may shed some light on the problem.

When I was researching LED / compact fluorescent / metal halide lighting it cleared up a few problems where lamp specifications were concerned.
 

amirm

Banned
Apr 2, 2010
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Seattle, WA
Data/presentation projectors are completely different animals. They are pushed harder resulting in shorter bulb life. They also use white segment if they are DLP as the response from PJ Central says. Contrast is also always lower. In general, they make poor home theater projectors.
 

Mark (Basspig) Weiss

Well-Known Member
Aug 3, 2010
678
31
940
New Milford, CT
www.basspig.com
I'm aware that presentation projectors use a different technology to get higher published numbers, but I'm supposed to be comparing home theater projectors. InFocus' new entry is a HT projector, has a much lower wattage bulb, but claims higher lumens. But the calculator at projectorcentral shows it puts 1/3 less light on the screen, comparing movie modes on both it and my existing unit with a much higher wattage lamp. I e-mailed them and called them out on this, but the response has been the sound of crickets.

Another thing that's vexingly frustrating is that to get native 2.35:1 (2560x1080), one has to spend 50X as much money as a good 16x9 projector! Three times the purchase price of my first home seems way out of line with what an item you put IN the home should cost.
 

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