The question of required lumen output has been raised by us all at one time or another. I've read countless threads in which people have asked if a certain projector would be right for their room, or if a particular screen-size suited a particular projector. I'm of course interested in this now since early this spring I'll be upgrading my 720p projector to a new 1080p model. But as I search for ideas of what my next purchase might be, I can't help but wonder how important high numbers of lumens are for a dedicated home theatre room with 100% light control, dark walls, floor and ceiling, as well as non-reflective surfaces? Or, instead on lumens, does a good picture have more to do with the projector's ability to display decent contrast and uniform brightness?

Here's my situation. My two year-old Panasonic AE900U (the specs say 1100 lumens) has about 900 hours on the bulb and is fully calibrated with the best contrast it can give me. It's running in low-lamp mode and is 19.5 feet away from a 118" diagonal Carada Brilliant White screen. It's housed in a custom-built wood cabinet in the back of my home theatre that is as projector-friendly as can be. I'm still amazed at the picture. Now, without the benefit of a light-meter, I'm guessing that the lumen output is somewhere in the ballpark of 200-300 and I'm plenty happy with the image. If this is the case, and since I always use the projector in a totally dark room, do I really need to worry about getting the most lumens for my buck? Or is it the total package that I should be concerned with? And in the room I described above, would any respectable projector suit my needs if it had say, 700 to 1000 lumens?

A long, long time ago in a far away land, I owned an LCD projector that was fairly bright. I went to an HT meet in my area where the guy had a "HUGE" IMO CRT on the ceiling.
Well I watched the pic for about 15 min. and said to myself, self "Self, I want that".

Proceeded to find a projector with better contrast and black level.(DLP)
I now have a Sony Pearl, which I really enjoy.
So in my opinion, in a light controlled theater, lumens is not the be all end all. I will say I run a Highpower screen. Bottom line, it's a combo of all things combined. (IMO)

Scott

For the answers to your questions here and a lot more just click on the link in my signature.

Some people really need the extra brightness, many don't.

Each group seems to think that they represent the typical case, or an important majority. The reality probably lies somewhere in between. The more options that are available the better, I think.

First read Bob Sorel's link.

Sufficient lumens are needed to ensure that you see color vision at maximal resolution. The recomendation is 12-14/foot-lamberts. However you actually can see more detail with more light as long as you don't need sunglasses. As with all things the law of diminishing returns kicks in with visual acuity. The second problem becomes one of fatigue of the iris as it opens and closes in a movie setting. Thus the recommendations which are founded on very limited data.

You'd get varying answers on how important lumens are depending on who you ask. I imagine you would get a different opinion from the guy with a 13' throw and 100" Diag screen compared to a guy with a 22' throw and 130" wide screen. My projector has 3,000 lumens (3 chipper) projecting onto a 120" wide perf screen from 23' away. I would not go to a projector with less lumens. It really does make a huge difference to me. Lumens is a big determing factor. Not the only one, but it is the first one I look at. My setup probably isn't the typical theater setup, so what is important to me might not really be as big of an issue to others.

As our eyes age they need more lumens for the same acuity of vision. Hollywood mirrors have bright lights on both sides or all around to minimize shadows and maximize acuity.

imho home theater projectors for the most part arent bright enough

i'd say mostly for the aging side effect: a lamp loses quickly lumens after just a few hundred hours.

a projector should either offer 2 3 different lumens output (from 300 to 1500) or the same projector should be made available in 2 different brigthness range (1000-2000ansi real lumens at 6500K and not at 10,000K...) and 400-600lumens ( for the black home theater with medium small screen).

Is there too much emphasis put on lumen output?

Bob goes into great detail in the link in his sig, but to summarize that, it all depends on your application. To paint in very broad generalities, for screens probably under 96" diagonal or smaller, brightness isn't really an issue as it only takes 300 Lumens or so go light those to 12 ftL (assuming 1.0 gain). Coincidentally (or not), I'd venture that that's probably about the most common HT screen size.

It becomes progressively more and more of an issue as you increase screen size.

I would agree with most everyone. The combination of personal preference, room design, type of content (sports with lights on or dedicated bat cave) all factor in.

I just bought a 777 for a 96x54, possibly 100x56; scope of 127 or 132 width. For me 1300 starting lumens (typical reported measurment) is the ticket. My wife can watch tennis with enough lights on that the kids can play. A typical 1080 PJ calibrated would not make me happy.

The happy part is the key. YOU and yours have to like what you end up with.

[QUOTE

Sufficient lumens are needed to ensure that you see color vision at maximal resolution. The recomendation is 12-14 ft/lumens.[/QUOTE]

I think it's important to point out the typo in your post; I am most certain you intended to say 12-14/foot-lamberts.

As stated earlier, it depends, BUT

both the ability to have a single purpose light controlled screening room and having the viewing practices that rarely or never require a semi-lit room are both necessary and increasingly small subsets of the FP world. At the top end of the market at least the former of these two factors is assumed. BUT For the meat of the market, where the volume is sold (and where the manufacturers make the profits that justify their FP R&D) neither of those factors are, or should be assumed. In the volume and growing part of FP market, where the projectors cost about the same as high end televisions, the vast majority of users (and therefore the vast majority of FP users) are going to be operating in living rooms, game rooms or at best, repurposed dens, where contrast is environmentally limited and lumens are king. As well, these are the folks who buy big screen tvs for football season and the superbowl (ask at big screen dealer over the past 20 years what drove the vast majority of his/her sales, and the answer will be football) and they are expecting to show off their 100inch screens to their friends in rooms where they can still see the chips, dip, and beer fridge. I know that while I enjoy watching Bladerunner in the darkest room I can manage, my superbowl and other viewing parties are done in semi-lit rooms.

Ok, maybe a simpler way to put this - for years FP has been driven by video hobbyists/film buffs who want, literally, their own home theatre. As FP grows, and by growing justifies more rapid product releases and more R&D investment, the number of videophiles are being dwarfed by the the number of more casual "no substitute for diagonal inches" viewers for whom a different set of specs is most important.

The good news, an true videophile can now buy a $3000 black pearl for their custom built garage theatre and for 6-7k have what cost an out-of-reach 30k+ a few years back. That doesn't mean for the hobby to grow that we don't need bigger, more powerful light cannons that can throw a quality image at the same time.

More light!....I personally believe the future is having a wall (giant screen) lit up like a LCD screen that you can watch anytime....Not just in a secluded bat cave. I have one in the basement and one in my great room...I find my family and I spending way more time in the great room on the main floor of the house...;) Projectors are becoming more and more popular...Yep....They are moving from the bat caves to the living rooms...:)

jdlynch
typo fixed.

Large lumens are needed for the future to have darker colored screens in patially lit rooms. Foot lamberts are equivalent to lumens x screen gain / square feet of screen.

I want a very large screen (lots of lumens). Didn't THX once have a 30 degree viewing angle requirement from the seats?

Sometimes that is the case. It is a lot like resolution...many think more is better. Thought light output can be critical for certain applications, dark/dedicated rooms don't require as much to acheive a good picture. Some of it is personal preference, too. I had a 103" Silverstar for a while, which always put out a super bright image. Now I went to a 53"x124.5" 2.35:1 screen. I am using a Sim2 D75/Panamorph UH380 combo, which is not a light cannon. But, it still lights it up plenty for me (I think my preferences are shifting to a more CRT/filmlike image as opposed to a plasma-like image I used to get.
http://www.avsforum.com/avs-vb/showthread.php?t=888908&page=2