Sorry if this is elsewhere but if the RS-1 only gonna be 700 lumens--sounds awfully low. Anyone know anything about this? Thanks

Sorry if this is elsewhere but if the RS-1 only gonna be 700 lumens--sounds awfully low. Anyone know anything about this? Thanks

Viper, I think you will find that brightness of this projector is well discussed and reviewed on this forum as well as others....
in addition, don't get too hang up on actual numbers IMHO, but judge by yourself and try to get to a demo and see it with your own eyes.

700 true lumens at D65 is actually quite bright. Most HT projectors claiming 800-1000 lumens are nowhere near this when calibrated for accurate colours.

700 lumens

Yes, I have seen it, its a terrible projector. SO dull and SO noisy! And as for that ANSI CR rating! I wouldn't even bother demoing... There are lots of lovely Runco projectors out there that are much better, you can tell because they cost lots of money.

700 lumens is only at min throw distance,
actual lumens likely less depending on you set-up.

I have found far lower lumen levels when pointing my meter at the back wall from the back of the projector. Far less than 700.

As others have said...700 D65 lumens is actually above average. The only projectors that have more are a couple LCD's and the 3 chip DLP's.

Glad Jason posted that. Most likely sets some minds at ease.
Seems like there are several ways to measure lumens. Also seems like CRT projectors are measured differently than digitals.
I don't pretend to understand the whys and wherefors, but would greatly appreciate, if the more knowledgeable could sort it out for this neophite. :confused:
How does one know if a projector will have satisfactory brightness, according to the values posted by manufacturers or reviewers.
Tony...

Glad Jason posted that. Most likely sets some minds at ease.
Seems like there are several ways to measure lumens. Also seems like CRT projectors are measured differently than digitals.
I don't pretend to understand the whys and wherefors, but would greatly appreciate, if the more knowledgeable could sort it out for this neophite. :confused:
How does one know if a projector will have satisfactory brightness, according to the values posted by manufacturers or reviewers.
Tony...Tony, I'm in the same boat as you - just figuring this stuff out and spending time here trying to learn something so please take this with a grain of salt. But from what I understand so far, the best way to figure it out is to take the ANSI lumens at D65 (700 for the RS1 in high lamp and 580 in normal), then calculate the resulting Foot-Lamberts for your application. To do that use the following formula:

ftL = (Lumens * Screen Gain) / Screen Area (sq.ft.)

I have a 1.2 gain 127"W 2.35 screen, so I will get the following results:

Normal Lamp (1.78): 19.3 ftL
High Lamp (1.78): 23.3 ftL

Normal Lamp (2.35): 14.6 ftL
High Lamp (2.35): 17.7 ftL

There are a couple of other factors as well: lamp will drop in brightness with age (I figured maybe 20% before I would just replace it) and the zoom. For me there is an additional consideration with a 2.35 anamorphic lens dropping the brightness further.

I found it a little bewildering at first (and still do to some extent), but from what I gather I'm aiming for over 12 ftL. My only concern given the numbers above is 2.35 movies in normal lamp. But then again, I will be watching that in a total light controlled room and I think that is one application (movies) that is a little less demanding of bright light. When watching HD sports, I would be using High lamp in 1.78 so would get over 20 ftL which should be more than enough. Once I understood this my original concerns about light output were pretty much put to rest. Anyway, my $0.02 FWIW.


EDIT: One thing I really don't understand yet though is the interaction of contrast ratio and "perceived" brightness. Anyone want to take a crack at the "Contrast for Dummies"?


Craig.

As others have said...700 D65 lumens is actually above average. The only projectors that have more are a couple LCD's and the 3 chip DLP's.

Assuming the RS-1 actually tests out on the "Turk-o-Meter" at 700 lumens after calibration.

Agreed, I'll believe it when I see it. I'm guessing 550.

How does one know if a projector will have satisfactory brightness, according to the values posted by manufacturers or reviewers.
Click on the link in my sig...Yet another shameless, self promoting plug...:p

I figured maybe 20% before I would just replace it

If you plan on replacing bulbs when they lose 20% of their lumens value, then save yourself some time and just buy a dozen bulbs with the projector.
Most probably lose 20% in the first 50-100 hrs.

I am planning on getting an HD-1 for our living room, which has an open window but is quite dark in the evenings when we draw the shades. The screen would be a 106" diagonal Da-Lite Hi-Power, which would drop down in front of an (upcoming) 65" Slim JVC RP set for daytime and casual viewing. Throw distance will be 17.5 feet, with the HD-1 mounted on an eye-level shelf on the rear wall of the room (just to the side of a couch). We have a white ceiling and beige rug (medium brown walls), so I am counting on the retro-reflective screen to prevent light from bouncing off the ceiling and floor. Interpolating from cine4home measurements, this throw range should yield 460 D65 lumens in low mode and 570 in high, while the lamp is new. With this screen size (33 square feet) and Hi-Power gain, two of us (adjacent couch seat and a different, closer couch seat) should be pretty close to the peak of the gain curve, and see 48 FL in high and 40 FL in low mode. I admit to being influenced by Tryg's Hi-Power review, and am looking for "punch", as well as the potential for day-time viewing.

My question is, am I overdoing things, and would this be "too bright"? Also, if it were too bright, why can't I simply dial down the brightness using the projector controls, instead of adding an ND filter? There are other seats on the first couch, and a third couch, that would see the image at lower gain, but they are still likely to be between 0.7 to 1.2 gain. I could go with a lower gain (~1.2) screen and equalize the viewing experience across the room, but am a little concerned about low teens FL as the lamp ages, as well as reflections off the ceiling and floor. Any advice would be appreciated.

" if it were too bright, why can't I simply dial down the brightness using the projector controls, instead of adding an ND filter?"

You could, but you lose CR in direct proportion, because you're only lowering brights, not blacks.

That said, with the RS1's very low black level it will probably work just fine.

So, like many, I cannot quite envision what 700 lumens looks like, but I can pretty well recall various Pearl set-ups. The Pearl juuuust did not have quite enough sharpness, quite enough contrast, or quite enough BRIGHTNESS. So how would the two compare? I think that might help both myself and others to get a feel for the RS-1.
I am considering the RS-1 for a 92+ diagonal screen with about a 1.3 gain (maybe the Stewart G-3 or 130 )...with a throw of about 14' I have seen the Pearl on a 92" screen from about 16' throw. Hoping for a little better in those areas of (1)brightness, (2)contrast, and (3)a little sharper. ;) Thanks for comment.

the problem is that we are comparing apples and oranges. On one side we have the JVC that probably comes very close to the 700 lumens and on the other side you have projectors that are rated at 1000+ but when actually rated, wind up near or below 700 lumens

Daniel:

How can you say the JVC "probably" comes close to 700 and others rated 1000 and above are lower than their claimed numbers? What data do you have to support that and what other PJs are you referencing? Have you tested the JVC against these others?

Daniel:

How can you say the JVC "probably" comes close to 700 and others rated 1000 and above are lower than their claimed numbers? What data do you have to support that and what other PJs are you referencing? Have you tested the JVC against these others?

This has been discussed ad-nauseam in many reviews of pre-production and production RS-1/HD-1 projectors. The JVC rating is at D65 calibration. Other projector specs are before calibration.

Noah: Thanks for pointing out why people use ND filters. I have found your other posts to be very informative. In a fully darkened room, does a high FL level (20-30, 30-40) cause you to wince at whites and wish the screen was dimmer, or is it "punchy" and desireable? I presume that in an environment with ambient light, it would be hard to overdo the FLs.

700 lumens out of a 15,000:1 contrast projector has to be a light canon. My 4805 is about 600 lumens (in low lamp mode) calibrated at only about 2000:1 contrast and it's a freakin light canon. It even fills 10.5 x 5.9' very brightly on my pale grey wall.

Say the 4805 is 700 lumens in high power lamp mode its blacks are quite a bit brighter than the RS-1's, which means the dark end is adding more measured light output than the RS-1's.. The fact that the RS-1 can achieve anywhere near 15,000:1 at 700 ANSI lumens much mean that it has a clearly brighter white end to make up for its darker blacks (which SHOULD be darker).

So, the RS-1 should have clearly brighter whites than the 4805, which is a light canon itself. Therefore, even at the same lumen rating the RS-1 should appear clearly brighter than the 4805.

92" screen from about 16' throw. Hoping for a little better in those areas of (1)brightness, (2)contrast, and (3)a little sharper. ;) Thanks for comment.

Well, when people say sharpness, I think of MTF, which is a function of so many things (and isn't really measured anyway) that it's very difficult to make any sort of educated comment.

As far as contrast goes, the overall edge goes to the JVC, with the intra-image dynamic range (GregR's terminology, not mine) being much higher on the JVC in low APL scenes. I'm not going to pretend to understand all of the intricacies involved in comparing the contrast of a DI projector to a non-DI projector, but we do have threads around here dealing with that very thing. My take? the JVC is a step forward.

As far as brightness goes, well, if you're talking about max lumens post-calibration it seems to me that the Pearl and the JVC will be very similar.

If you were really that unhappy with the Pearl (I do enjoy mine), I suggest you get a closer look at the JVC to draw your own conclusions.

Say the 4805 is 700 lumens in high power lamp mode its blacks are quite a bit brighter than the RS-1's, which means the dark end is adding more measured light output than the RS-1's.. The fact that the RS-1 can achieve anywhere near 15,000:1 at 700 ANSI lumens much mean that it has a clearly brighter white end to make up for its darker blacks (which SHOULD be darker).


I'm not sure I follow this logic. Aren't lumens measured on a 100 APL test pattern? If so, there is no "dark end" adding light to the image in these measurements.

I could be wrong. I've never measured lumens before.

Kevin,

"I have found your other posts to be very informative. In a fully darkened room, does a high FL level (20-30, 30-40) cause you to wince at whites and wish the screen was dimmer, or is it "punchy" and desireable? I presume that in an environment with ambient light, it would be hard to overdo the FLs."

Thanks for the compliment.

I can't say for sure, never having measured what brightness I'm getting. My is guess that 40 ft-L in a dark room would be approaching winceworthyness.

Personally I wouldn't want a pj that's inwincible :) I'd just add some judicious backlighting to take the edge off.

Daniel:

How can you say the JVC "probably" comes close to 700 and others rated 1000 and above are lower than their claimed numbers? What data do you have to support that and what other PJs are you referencing? Have you tested the JVC against these others?

viperdrummer:

Please don't take this as rude, as it really isn't meant to be; however, the fact that you started this thread for the stated purpose and then questioned Daniel about what frankly, at this point, is common knowledge shows that you simply have not read the other JVC threads regarding this pj...I know the threads have gotten long, but if you really want info on this projector, it's already here in spades...do the reading.

Regards.

I'm not sure I follow this logic. Aren't lumens measured on a 100 APL test pattern? If so, there is no "dark end" adding light to the image in these measurements.

I could be wrong. I've never measured lumens before.

I'm not really sure either, so you could be right. I was just talking about what I thought might be the case really.

My 4805's fade to black is VERY bright though compared to my CRT projector (obviously) and black always has this level of light output and it looks darker when there is bright lights around it. I'd be very suprised if that level of light wasn't registering.

Either way 700 calibrated ANSI lumens from any decent contrast projector is very bright. I mean some 7" CRTs rate about 150 ANSI lumens and they look awesome. Although I suspect their ratings to be a bit higher with gamma correction, but still.

I usually run my 4805 on my 8' wide super high gain silver torus, but I swear on my pale gray matte wall at 10.5' x 5.9' with the image bounced off of a regular mirror (which no doubt causes at least 5-10% in light loss) so I can reach that size it still looks very bright in low lamp mode, which is rated at 600 lumens. I have a bit over 300 hours on the lamp right now. So, 700 sounds low when you read about all these projectors rated at 1500-2000 lumens or so, but it doens't appear low in reality.

Sorry if this is elsewhere but if the RS-1 only gonna be 700 lumens--sounds awfully low. Anyone know anything about this? Thanks

lol do you know the brightness of a marantz or a benq or a sharp ? :D

you'd revise yr judgement

the HD1 is bright enough that the demos in Germany and Franceboth were on a 400cm wide 16/9 screen in a black room
of course in a white living room one would need 3000ansi real

the problem is that we are comparing apples and oranges. On one side we have the JVC that probably comes very close to the 700 lumens and on the other side you have projectors that are rated at 1000+ but when actually rated, wind up near or below 700 lumens

i'd say 350-400 ansi from those 1000-1200 ad figures.

JVC is one of the brands that is quite fair on its specs.

HD10K: 550ansi 2400:1 at D65
HX2: 550ansi 1700:1 at D65
HD1: up to 830ansi 18000:1 :D around 7500K

Apologies to Daniel and others--I should have done more reading.

In a fully darkened room, does a high FL level (20-30, 30-40) cause you to wince at whites and wish the screen was dimmer, or is it "punchy" and desireable? I presume that in an environment with ambient light, it would be hard to overdo the FLs.
My personal take on this is the "standard" around here of shooting for ~16-12 ftL is on the dim end for anything other than dark movies in a dedicated dark theater. Again, this is my personal preference. I have one of my two PJs set up to around 12 ftL and the other in our BR set up above 30 ftL since there's often AL in that room to deal with.

The darker PJ (an LCD) is great for watching darker movies... even though the black levels aren't great this particular PJ (yes, I'm looking forward to the RS!! :D) It's easy on the eyes and easy to get into the mood when watching something like Silent Hill or Harry Potter. With that said, it is on the dim side IMO for anything else. Brighter movies such as comedies could use some more brightness IMO. There isn't a lot of in your face plasma punch by any means at this level and you really NEED a very dark room to achieve good PQ.

The other PJ (DLP) is much more vivid and plasma-like with its bright picture (~30 - 35 ftL). The room is dark at night, similar to a proper theater. Everything is simply brighter and more vibrant. I'm sure you've seen a plasma display, it really is very similar... just larger. Even with some AL in the room, the picture is still quite acceptable, which certainly can't be said about the other screen at ~12 ftL. There's nothing 'painful' or even stressing about watching the image at this level of brightness, but it's not really relaxing or soothing either (which the 12 ftL screen can be). Whites aren't blinding, but they are bright and colors just jump of the screen at times. Sports are a treat to watch as is anything that isn't dark and moody, if that makes sense. The image is just too bright for these dark movies as the darkest of scenes are a little too bright.

I think if I had only one PJ to use for all purposes, I'd probably have the PJ mounted close to the minimum throw so the image was around 20 ftL (new bulb) when fully zoomed in to fit the screen. I'd then shrink the image down when I wanted a brighter picture. Granted, this isn't ideal, as the image is now much smaller and it doesn't fit the screen... But, I'm not one to only watch movies with my PJs either and 12 ftL just doesn't cut it for watching a football game with a light on in the room! If you have a dedicated bat-cave theater and only watch movies, 12 ftL might be great, but for anything else I think a little more punch is needed.

Just my 2 cents.

So, the RS-1 should have clearly brighter whites than the 4805, which is a light canon itself. Therefore, even at the same lumen rating the RS-1 should appear clearly brighter than the 4805.
No. Max lumens have nothing to do with black level and contrast. If projector A has 700 ANSI lumens @ D65 with on/off CR of 1k:1 and projector B has 700 ANSI lumens @ D65 with on/off CR of 100k:1, both projectors would be IDENTICALLY bright. The black level of projector B would be 100 times lower than the black level of projector A.

Lumens are an absolute figure of merit, not a dependent figure. If lumens are measured correctly (when the entire gray scale is properly calibrated to D65), then you can simply compare the numbers from one projector to the next to see which is the brightest. The problem is that manufacturers (and less competent reviewers) measure lumens on uncalibrated units in order to give marketing as high a number as possible to publish, so comparing most manufacturers' claims to accurately measured D65 light levels has no meaning. Even among competent reviewers the equipment and techniques used can vary from person to person, so for best results I recommend either measuring the lumens yourself or using numbers from the same source.

And then don't forget that lamps lose brightness VERY quickly. So for fair comparisons, it is best to compare lamps that are brand new (second best is with lamps with the same amount of hours, but since they can lose brightness at different rates, that is not the optimum method). Most lamps will lose half their brightness in anywhere from 250 to 500 hours regardless of manufacturers' claims. So, for example, it would be totally unfair to compare the brightness of a projector that has a lamp with 200 hours on it to a projector with a brand new lamp. Even the difference of 50 hours could have a significant impact on brightness, so be very careful when making observations.

I've owned CRTS (80s thru mid 90s) and then DLP projectors. I was thinking about buying the Sim2 HT3000 before all the hysteria concerning the RS1 broke out. I'm on the pre-buy list for the RS1, but the low ANSI figure (I know, typical for an Lcos unit) and fear of a lack of "punch" has me concerned. Also, black levels are constantly trumpeted, but one reviewer said he though bright scenes had a slightly washed-out look compared to DLP.
Will I be buying into a machine with great blacks but at the expense of the "plasma" look in bight scenes? Obviously, I've never seen the RS1, just read about the perfermance here and elsewhere.
I've noticed many posting here who've seen the RS1 and like it are currently using Sony or JVC projectors (same display characteristics).

TA

Wet1: Thanks a lot. I think I will go ahead with the High-Power and take all the lumens I can get. The downside is not everyone will get the punch if there are visitors, but it should be no worse than 14 FL for the furthest seats.

Timbelmont,

If you like the "hard edged" look of DLP, you probably won't be happy with the RS1. The much used term, "film like" is an attempt to describe the visual smoothness of a DILA image versus a DLP image. This is a personal preference issue much like the ongoing color gamut arguments.

DLP projectors in a dark environment give me headaches, end of story.

I saw the RS1 prototype at CEDIA and immediately fell in love with it. TO ME, it was the best overall image I viewed and at an unbelievable price.

Wet1: great post. Your comments are certainly the conclusion I've come to in reading about all this for a year or so. I've never had a pj, but am on the prebuy for the RS1, and planning to use a HP screen to get the 30+ ftL.

By my calcs for my setup I get the follow:
Lumens --> FTL
700 --> 23.59
600 --> 20.22
500 --> 16.85

Question - What effect does screen gain have on this and how do you calculate it in? I use a Studiotek 130 (1.3 gain). And how do you calculate throw distances into the equation? I'll be shooting from 15ft.

Based on my initial calcs if the RS1 produces 700 lumen at D65 and then tapers off to 500 with age I can be happy. If it gets much lower it could get a bit dim. Now if screen gain and throw can help it would be a bonus.

just multiply your results by the gain. (1.3 in your case)

Based on my initial calcs if the RS1 produces 700 lumen at D65 and then tapers off to 500 with age I can be happy. If it gets much lower it could get a bit dim. Now if screen gain and throw can help it would be a bonus.
That's wishful thinking, Kraig. If you get 700 lumens initially you had better figure on 350 lumens by the time you get to 500 hours...maybe sooner. And it keeps going down from there, albeit at a slower pace.

Question - What effect does screen gain have on this and how do you calculate it in?
ftL = screen gain * lumens / sq. ft. of screen

Another good candidate that should click on the link in my sig...;)

i disagree with the statement that 12ftl is only good in a bat-cave theater.

I think most people would be suprised how little ftl they are getting, taking bulb age into account.

I think a bright image is great, but you adjust to the image as it dims. Sure a side by side most would pick the brighter image but I'm willing to bet people are watching images at less ftl's then they think and dont know the difference.

I think if someone has 12ftl after bulb age your in a good position personally bat cave or not.

Take a quick look at this thread. It does a good job of explaining the equations a has a nice example.

http://www.avsforum.com/avs-vb/showthread.php?t=753497&page=1

If you get 700 lumens initially you had better figure on 350 lumens by the time you get to 500 hours...maybe sooner. And it keeps going down from there, albeit at a slower pace.


Bob-
Is it still that bad? I thought drop off like that was attributed to not having proper cooling for the bulb? I'm not disagreeing with you just wondering.

Ofcourse that would help support my arguement that most people dont know how little ftls they are getting and not know the difference.

That's wishful thinking, Kraig. If you get 700 lumens initially you had better figure on 350 lumens by the time you get to 500 hours...maybe sooner. And it keeps going down from there, albeit at a slower pace.
Bob,

This lamp light output/age comment has been mentioned repeatedly. I have searched in vain on the internet looking for supporting data and can't find any. Someone from JVC (I think) has stated that UHP lamp technology has improved significantly over the last several years. Are there any recent studies that support this position?
I just replaced the lamp in my HS10 and the old lamp (2100 hrs) output was only about 30% of the new lamp so I completely agree that earlier UHP lamps degraded rapidly. Is this still the case for newer designs?

Maddogmc-

I think that I may stick with the RS1 and if I don't like it, just get something like the Sim HT3000. The price on the RS1 is low enough where I won't be out much if that happens. One of you guys might even want to buy it. :)

TA

This lamp light output/age comment has been mentioned repeatedly. I have searched in vain on the internet looking for supporting data and can't find any. Someone from JVC (I think) has stated that UHP lamp technology has improved significantly over the last several years. Are there any recent studies that support this position?
No, there are no studies that I know of. My repeated comments are due to what are now 11 lamps that I have tracked (10 UHP and 1 Xenon) and every one without exception reached half brightness in less than 500 hours of usage - several of them in as little as 250 hours. This doesn't mean that YOURS will do the same, but as far as I am concerned, I would be happier than a pig in sh!t if I ever found one that went longer. So for me this is Gospel, and I plan my brightness needs based around 50% of the actual measured lumens of a given projector with a new lamp.

The only verification I can add to his would be in the way of having you question other enthusiasts like myself who have taken the time and trouble to track lamp brightness. You will NEVER get this information from a PJ manufacturer...;)
I just replaced the lamp in my HS10 and the old lamp (2100 hrs) output was only about 30% of the new lamp so I completely agree that earlier UHP lamps degraded rapidly. Is this still the case for newer designs?
So far I have seen no indication that lamps are getting any better, but there is always a first time...hopefully. :)

Wet1: Thanks a lot. I think I will go ahead with the High-Power and take all the lumens I can get. The downside is not everyone will get the punch if there are visitors, but it should be no worse than 14 FL for the furthest seats.
You guys will be happy with the HP, it's a great screen. One thing worth noting... the off axis image isn't all that great with the HP (if this is even a concern). While the gain is down off axis, so is the PQ IMO. The image becomes a little muddy off axis. So while you might think a gain of only say 1.0 off axis is still acceptable, beware the image quality will not be equal to a 1.0 gain matte white screen.

Good luck with everything. I'm sure you guys are as excited about getting your RS1 as I am. :)

Viperdrummer,

No offense taken. Although Lumens and contrast ratios are scientifically measured today , each company seems to have their own procedure for doing so and the real world numbers never seem to match. There have always been exceptions with the Infocus line typically being as bright as they claim and the Marantz having the contrast ratios that they claim.

The best explanation I heard was Sam Runco himself at a AVS party. He told us that in the early days if he saw a projector that was rated for example 600 lumens and he had a projector that seem to be twice as bright, he would claim that his projector was 1200 lumens. Now I am sure that doesnt happen anymore, but what is written on box and what you get after the bulb ages slightly and especially after calibration isnt what you wind up with.

What occurs is that if you have companies like JVC and Runco who measure their specs after calibration and compare them to companies that dont do any calibrations then, the calibrated projectors will always loose in spec comparison

That's wishful thinking, Kraig. If you get 700 lumens initially you had better figure on 350 lumens by the time you get to 500 hours...maybe sooner. And it keeps going down from there, albeit at a slower pace.

ftL = screen gain * lumens / sq. ft. of screen

Another good candidate that should click on the link in my sig...;)


I dont know about this for UHP bulbs. There was a survey posted on here a while back on Optoma H78/H79 UHP bulb degrade over time and at 500hours it was showing that the lamp had lost about 1/3 of its brightness.

Isnt the Xenon lamp in the Ruby known to loose lumens quicker than a typical UHP bulb?

I will start out at 22ftL on low lamp with a new bulb, and 28ftL on high lamp with a new lamp on the RS1 in a "batcave" with my setup up using C4H lumens numbers. So at 1/2 lamp life I will get 14ftL on high lamp. I would think I would be good, no? :confused:

I would not think you would want to go over 30ftL on a new bulb in a deadicated theater as this would elevate black level too much? Blacks will look a lot deeper and richer at 12ftL as opposed to 30ftL, correct?

Is it still that bad? I thought drop off like that was attributed to not having proper cooling for the bulb?
Yes, it is still that bad. It is curious that the longest lasting half life I have measured (500 hours) came from an InFocus 7210, and coincidental or not, it was also the noisiest (and probably best cooled) projector of the ones I have tracked. With the tendency towards quieter projectors, that indicates to me that they aren't being cooled as well as they could, and as a result may be contributing to even shorter lamp life. Of course this is all speculation on my part and I have no proof, though my trackings support my hypothesis.

I dont know about this for UHP bulbs. There was a survey posted on here a while back on Optoma H78/H79 UHP bulb degrade over time and at 500hours it was showing that the lamp had lost about 1/3 of its brightness.
How many respondents had meters and knew how to use them? This is not something that can be judged by eye, as the eye's response to light is logarithmic. So, basically, is someone "eyeballs" a 33% decrease in brightness, in reality they have probably lost something like 60% of actual output.
Isnt the Xenon lamp in the Ruby known to loose lumens quicker than a typical UHP bulb?
yup...That was the one that reached half life in 250 hours...:(
I will start out at 22ftL on low lamp with a new bulb, and 28ftL on high lamp with a new lamp on the RS1 in a "batcave" with my setup up using C4H lumens numbers. So at 1/2 lamp life I will get 14ftL on high lamp. I would think I would be good, no?
That sounds extremely good to me! You have a great plan! It may even be too bright for a short time when brand new, but I'm sure you'll suffer through it...;)

How many respondents had meters and knew how to use them? This is not something that can be judged by eye, as the eye's response to light is logarithmic. So, basically, is someone "eyeballs" a 33% decrease in brightness, in reality they have probably lost something like 60% of actual output.

yup...That was the one that reached half life in 250 hours...:(

That sounds extremely good to me! You have a great plan! It may even be too bright for a short time when brand new, but I'm sure you'll suffer through it...;)


I will manage somehow I guess :p Thanks for the info Bob! :)

The only verification I can add to his would be in the way of having you question other enthusiasts like myself who have taken the time and trouble to track lamp brightness. You will NEVER get this information from a PJ manufacturer

Thats why I asked you my question :)

I defiantly appreciate you taking the time to do the tracking and I don't doubt your findings the least bit.

I would also like to point out though visibly the difference between half the lumens wont equal the perceived difference of half the brightness (as shown in the polls of people selecting 30 percent loss in brightness).

Thanks for the responses about FTL calcs. Now figuring in screen gain my numbers look like this:
Lumens --> FTL
700 --> 30.67
600 --> 26.29
500 --> 21.91
400 --> 17.52
300 --> 13.14

The thing I still don't know how to calculate is lumens drop off based on throw. Any ideas?

wait for cine4home.de review this week. it will give you a better idea of lumen drop offs.

Bob,

When you measure brightness from a projector what do you have the projector displaying. Is their a standard white which is projected.

Yup...I use a 100% stimulus full field white pattern. In order to have projectors on a level playing field, I first do a full grayscale calibration to D65 and then turn up white until it drifts off by a dE of 3 (That's my standard. I think Greg uses dE of 2). This way I can measure the maximum brightness obtainable before 100% white begins to clip any of the primaries (in other words before it starts to change color temperature).

wait for cine4home.de review this week. it will give you a better idea of lumen drop offs.

Good point. I hope they measure lumens at the min and max throws. Generally speaking though the closer your pj is to the screen the higher light measurement you would get, right?

yes the closer the throw the higher the lumesn the longer the throw the higher the contrast.

I'm pretty sure cine4home.de will give both measurements in their review.

"And then don't forget that lamps lose brightness VERY quickly. So for fair comparisons, it is best to compare lamps that are brand new (second best is with lamps with the same amount of hours, but since they can lose brightness at different rates, that is not the optimum method)."

Since most of us don't get to watch with a brand new lamp for very long, I think it would make more sense to pick a point somewhere in the middle range of the life curve, say 300 - 500 hr.

"the off axis [HP] image isn't all that great with the HP (if this is even a concern). While the gain is down off axis, so is the PQ IMO. The image becomes a little muddy off axis."

To me it just looks dimmer.

"Blacks will look a lot deeper and richer at 12ftL as opposed to 30ftL, correct?"

Maybe in a really dim scene, but the eye keys mostly off of CR, not absolute brightness.

At a minimum the higher brightness causes the eyes' iris to close down, making the darker portions appear blacker.

Many with bright pj's have said it actually increases perceived CR.

Take a quick look at this thread. It does a good job of explaining the equations a has a nice example.

http://www.avsforum.com/avs-vb/showthread.php?t=753497&page=1THANK YOU!! And thanks Bob!! This is exactly what I was looking for.

The only verification I can add to his would be in the way of having you question other enthusiasts like myself who have taken the time and trouble to track lamp brightness. You will NEVER get this information from a PJ manufacturer...;)
Thanks! Hopefully, we can get a few people to do measurements on a regular basis and report back. Maybe there needs to be a specific thread (sticky?) where lumen output for different projectors and/or lamp types can be tracked over time. AVS Forum members could produce the first real, documented history of lamp light output characteristics!

Kraig,

I think I read somewhere the throw on the RS1 is 1.4 to 2.4x width. I believe, that ekkehart had the 695 lumens at min and 525 lumens at max. Roughly a 170 spread. Based on that, guestimate a 17 lumen drop for every .1x throw over 1.4. So if your throw is 1.8x 16.9 width than lumens guess could roughly be 695-(17x4) or 627.


Might be too much simple math. That depends on a linear drop off with distance from his max to his min. You might want to verify that min lumens measurement of his. It might be on his web page, and it also could have been off of a post he responded to lovingdvd on.

You guys will be happy with the HP, it's a great screen. One thing worth noting... the off axis image isn't all that great with the HP (if this is even a concern).

How far off axis before the picture quality degrades?

Kraig,

I think I read somewhere the throw on the RS1 is 1.4 to 2.4x width. I believe, that ekkehart had the 695 lumens at min and 525 lumens at max. Roughly a 170 spread. Based on that, guestimate a 17 lumen drop for every .1x throw over 1.4. So if your throw is 1.8x 16.9 width than lumens guess could roughly be 695-(17x4) or 627.


Might be too much simple math. That depends on a linear drop off with distance from his max to his min. You might want to verify that min lumens measurement of his. It might be on his web page, and it also could have been off of a post he responded to lovingdvd on.

Catdaddy - very cool thanks. Bob Sorel - thanks for all the great info, you're on a roll.

So here is my latest round of calcs. This assumes the 695 lumens at min throw and 627 at max and then my situation in between which Catdaddy calculated at 627. I added % of lumens lost in 10% increments to 50%. I hope it doesn't lose more light than that.

%loss
lumens lumens ftl
New -- 627 --> 27.47
10% -- 564 --> 24.71
20% -- 508 --> 22.26
30% -- 457 --> 20.02
40% -- 411 --> 18.01
50% -- 370 --> 16.21

Still not bad but if you can't add light to my situation I just don't want to hear anymore :p :rolleyes:

Ive been messing with a bunch of calcs myself, as well, Kraig. The two biggest uncertainties for me are the gain from the Carada, which some very knowledgable folks in this forum have measured at 1.1ish and a very knowledgable reviewer measured at 1.4, and the light loss from the panamorph lens, which is somewhere in between 5% to 20%. The closer to 1.4 on the gain the more I can afford the loss even at 20% and the closer to 5% the more i can afford the gain towards 1.1, but I dont like the sound of having both at worst case. 8)

Cat - I thought Carada materials were .8 (grey), 1.0 (classic white), and 1.4 (brilliant white). That is my recollection. Are you saying Carada is overstating their gain? Just curious. Makes me wonder about my Stewart..

I linked to a reviewer who reviewed/tested the screen at 1.4 gain but we have some knowledgable folks who have stated that their analysis/reviews showed a 1.1+ gain. Since it is angular reflective, I guess differences could be attributable to many things but Im allowing for a worst case scenario in my calculations. 8)

http://www.presentingsolutions.com/Manufacturers/Carada/Screen_Criterion_16x9/index.asp

How far off axis before the picture quality degrades?
You have to get pretty far out of the cone. Keep in mind the brightness will drop off as you work towards the edges of the cone, but it is very progressive.

Well, then maybe someone can help guide me with my upcoming projector purchase. I am replacing my VP12S1. I have it 18 feet back, projecting on a 110" Firehawk in my dedicated theater. The picture is good (by good I mean bright) for about 700- 800 hours. My recall is that the lumens on the VP12S1 was 700. So the RS-1 would be significantly brighter than the Marantz? How would it compare to the Infocus 777 in terms of brightness?

Maddogmc-

I think that I may stick with the RS1 and if I don't like it, just get something like the Sim HT3000. The price on the RS1 is low enough where I won't be out much if that happens. One of you guys might even want to buy it. :)

TA

This is the attitude I am taking as well. I, like you, remain a bit concerned about the low ANSI contrast and relating issues of image "depth". The problem is that I really don't see too many alternatives for my 123" 1.3 gain screen. I am intrigued by the Sharp 20K, but it seems it would be too dim for my screen. I dont think the Sim 3000 is any better in this regard, is it?

I am intrigued by the Sharp 20K, but it seems it would be too dim for my screen. I dont think the Sim 3000 is any better in this regard, is it?

Not from what Jason just reported re the Sim 3000.

It's been speculated by some (including Alan Gouger) that Jason's HT3000 for whatever reason wasn't performing up to snuff. Other reviews indicate the brightness is good. Some insist Sim2 is using a brighter lamp in the newer production models.
I have a Stewart Greyhawk, but am upgrading to the Firehawk G3 (1.3 gain) in preparation for my RS1.

TA