New Foot Lambert Calculator

Thanks Mike!

I appreciate being able to see and adjust lumens. The one at PC doesn't show that value making the whole process much more of a mystery.

Here is some general info about the tool:
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Last Updated 9/18/2011

All the lumen numbers should be fairly accurate now, including the JVC and Sony. I am constantly revising them slightly as I see more and more reviews come out with different numbers so I can keep averaging them.

Calculator Real-World Accuracy:
Although my calculator should easily be the most accurate one on the Internet for home theater projectors, keep in mind that you might assume a variance of REAL WORLD results to this calculator of about 5% to 10% on average. It could potentially be as high as a 20% error margin on some of the calculations, but somewhat rarely. This will primarily be due to calibration variances on how each person calibrated or setup their projectors, but also partly due to MFR lamp variance and errors in measuring equipment or technique. Most of the lumens numbers are based on averaging out multiple measurements from multiple review sites and my own measurements when I had them.

What do the different modes mean:

Best Mode Lamp Low = This means after a proper calibration the expected brightness you will get.
Best Mode Lamp High = Same meaning as above, except with the Lamp running in high power.
Dynamic Mode = From Lamp High this is a somewhat subjective measurement of what the brightest somewhat calibrated mode might look like with a few concessions in accuracy (but not extremely far off) in order to maximize lumens.
Absolute Brightest Mode = This mode means the absolute brightest the projector can go with all settings unrealistically cranked up and blown out. This is not recommended for viewing and is only there to help establish baseline numbers.

Using your own Numbers
You can always find your own lumen numbers for any projector from a review site and plug them directly into the calculator. If plugging in custom numbers like closest throw that already take into account the position (like if a reviewer says Lumens measured at closest throw), then for my calculator you would choose closest throw option check box, but set the % adjuster to ZERO, this way the text in the results window will still say CLOSEST throw, but no throw modification to the actual lumens will be done for throw distance (which is what you want if you are using already adjusted values).

Feedback from Forum Members about my Calculator
I am currently looking for other programming ideas of any other useful tools, or if someone has an idea about adding a feature to it, please let me know, as I would love to hear your feedback. The tool was a completely original design written from scratch in Visual Studio 2010 - ASP.NET 4.

Why I made this tool
It was made for the benefit of projector users and new buyers alike, as I feel people are often matching the wrong projector to wrong screen gain. This project is most likely just a pre-cursor to a larger project. I am simply getting my hands dirty so to speak before I go all out with an entire review site and potentially even more home theater tools.

Known Bugs:
Occassionally an error may be thrown, simply reloading the page usually fixes it. The error seems to only occur occassionaly when selecting SCREEN GAIN. This will be fixed in the next version most likely, but it is not a crippling error. There are a few minor formatting and alignment issues with the page (will get to fixing these later). There are not ANY known bugs that affect the actual numbers, it should work AS-IS for the most part. I am not saying there are NO bugs affecting numbers, just saying not yet known at least, but I don't think there are.

You did a very nice job, coderguy. As a dabble-veloper myself, I would be mostly concerned about the upkeep on the information input into your app. It would also be nice if you could convince the PC guys to send you their db of projector stats for some cool retro.

I think in the long run, this is a tool that will be used very much and I am glad you took the bullet to develop it. When I go to PC, it's usually to mess around with their calculator, but now I'll use yours.

Very nice Coder!!! Thanks for the tool my friend!

Thanks guys, the data is fairly easy to maintain, actually very easy.

Please make this a sticky, so I don't have to go searching for it when I need it. Excellent job, coderguy!

question!

in the "Semi-Accurate Best Mode" are you still using low lamp mode, or the high lamp?
Since i have my HT in a livingroom with a firehawk, thats the mode i´m aiming for. I use my panasonic ae4000 on low lamp and in cinema 1 mode. My guess is that´s a bit brighter than a fully calibrated mode. Is that somewhat on par with your "Semi-Accurate Best Mode", or is it more like a calibrated "normal" mode with no colorfilter?

Very nice work on the calculator, i like it alot. Both fun and educational

Semi-Accurate is always high lamp.
Thanks.

How many FL is ideal for a 100% light controlled HT? Also, the JVC RS45 has more output in best mode lamp low and lamp high than the Panny A7000???

Very useful!

But according to the chart the RS60 has only 25 lumens less than RS35 in Best Mode (high). This isn't anywhere near the real world experience of most users as discussed ad-nauseam over the past 8 months, and certainly doesn't match my own experience with the RS60 and RS35...?

Where did these numbers come from?

Mark

Great tool !

Thanks.

Choosing a target Foot Lambert reading
How many fL depends on user preferences, your usage habits and lamp budget, 3D vs. 2D usage, whether the projector has a static-mode IRIS, and a few other factors. The standard is 14fL but you should also consider some bulb dimming over time. Without an IRIS, generally I'd say shoot for 16-22 fL in LAMP LOW for most users as a start because some of the lumens will be lost fairly quickly, this is as long as you do NOT mind dealing with a bit overly bright image the first couple hundred hours or so. If you are a heavy user and the projector has an IRIS and can drop below best mode with the IRIS fully closed, then find IRIS closed numbers before making a decision, as this could vary greatly. If you are a very light user putting less than 300 hours on the bulb per year, then I'd say 16fL to 18fL is a good starting target. Just my own estimations and it depends on the projector setup and how bright a person prefers the image.

For 3D it becomes more complicated, essentially you want to get as many lumens as you can, but you have to be careful because you will ruin your 2-D experience by having an image that is way too bright and cannot DIM enough. The brighter the image the more eye strain you will have. The way I handle this problem is I use a Da-Lite HP screen and shelf mount the projector, so I can control the gain, as the lamp loses lumens I lower the projector, eventually even floor mounting it if it doesn't have lens shift, but then again I am always looking for a way to save a buck. As long as someone is calibrating their own projector, many people will be fine using a number that is halfway between the SEMI-Accurate Non-Best Mode and the Best Mode Lumens (lamp high), but this will reduce lamp life since it is a HIGH lamp based number. This is because many projectors can calibrate a bit brighter than their Best Mode with only a few minor side effects to the image, but some projectors are better than others at this. Best mode is still the best mode.

Panny 7000 numbers vs. newer JVC's
From measurements so far, the Panny 7000's lumens drop more than most from its brightest mode to its calibrated modes. This is pretty standard for most Panny's even going back to the 3000 and 4000. The JVC's have more calibrated lumens and the newer JVC's are supposed to be even brighter than previous years. That said, I don't have accurate numbers for the RS45/55/65 just yet. Some of the other JVC numbers are also off a little more than normal.

JVC Numbers
I am still tweaking some of the numbers (mostly JVC), but these are difficult because there are so many conflicting measurements. This is another reason I have made it so that you can enter your own numbers. Some of the JVC's numbers are troubling due to many sources getting such different measurements. Here is one example, if I go by one site then the JVC HD250 is about 10% to 20% brighter than the RS10, and the RS-50 even 20% brighter than the RS10, but I know this site is wrong as the HD250 and RS10 should be less than a 10% brightness difference since they are basically the same projector, so I have to do my best to provide a more accurate number. I just re-averaged the numbers again with a slight bias based on what we generally know to be true.

The RS40/50/60 numbers also come out very different depending how you used the CMS, or if you have a lumagen versus calibrating without the help of a processor, so it is somewhat impossible to get these numbers perfect.

Even if the JVC reading is off by 10% to 15% in best modes (50+ to 70+ lumens), that's still within the error margin I noted, but then again some of the JVC numbers will get better as I spend more time analyzing them.

Update: I have found that most of the variance in lumens readings is due to some of the reviewers getting JVC's with used lamps as a review unit. I have modified the numbers slightly again, but still searching for user's that measured with light meters to average into the reviewer numbers.

The SMPTE standard is 14fL.

Tom,

You wouldn't happen to have any links to some of your posts with lumen measures, or lumens numbers you measured to share easily on hand, would you?

No problem if you do not, just curious...
I'm still averaging them all out.

I have tons of data, but it is all post-calibration. The pre-calibration data I have is not associated with a specific Picture Mode.

No problem, but just to clarify for others:

The calculator is an average of post-calibrated best modes, it does not consider factory modes in any fashion, even the absolute brightness measurement is lowered based on what a culmination of reviewers found. The Dynamic / Semi-Accurate Non-Best Mode is also based on a culmination of what reviewers considered a brighter but compensated non-accurate image to get more Lumens, and hopefully still good enough for some uses, although most would still prefer the best modes especially in movies. The numbers are often rounded up or down very slightly to the next 10 or 25 number just to keep it cleaner, but still based on actual averages of multiple calibrations and not factory specs.

Great program!

Any way to estimate the fL in 3D mode for those that support 3D?

Version 0.2 is about 50% finished and has 3D Calculations and a completely improved interface

I will post a screen-shot of the next version in a minute, I might be finished by tomorrow.

New Features

--Includes New Graphical Interface and sliders for Zoom and Throw Adjustments

--Added Statistics-- Things like Sample Throw Ratios (Min. Throw for 100" Screen) are shown for every projector, as well as Offset %, Weight, Dimensions, Motorized vs. Manual, Dark Chip version, etc...

--No longer is Throw Distance and Zoom a manual calculation
(uses Zoom and Throw Graphical Sliders sort of similar to PJC)

--Lambert readings are now shown Live and calculated in real-time next to each lumen mode, instead of just in the Final Report. This even works if you enter multiple screen sizes, for instance if you enter 92",110",120"; the program will INSTANTLY show a range saying 14fL (92") to 9fL (120"), and it is shown for every mode (Best, Brightest, etc)

--Now includes a 3D option to calculate a brightness loss for any mode by a percentage and include it in the report

--For 3D Projectors, Added IRIS Closed (Absolute Minimum Brightness) for projectors that have further room with their IRIS so that it is easier to tell the minimum brightness you can get for 2D on a projector with the 3D Modes and Lumens cranked up

--Dynamic Mode has now replaced the "Semi-Accurate Non-Best Mode". They are the same but it has been renamed.

I just bought a Mitsubishi HC4000 and am planning a CIH setup. Going by these calculations, to get a 49x115" 2.35 image, the 16:9 diagonal should be 130". Which means that I never get past 12fL under the low lamp best mode at any throw distance. And most people here seem to have a bigger image than mine, so I guess their fL will drop down even further. According to the calculations my mits is throwing up 8.5fL at farthest throw under best low lamp. But I find even this quite bright enough, and that's with my walls and ceiling painted white. I'm sure that if I darken the room, the perceived brightness of the image will improve even further. I guess what's an acceptable fL becomes a subjective issue.

I'm just stating this to reassure those using the calculator not to get too frightened by the low fL readings when planning a similar setup. Most people who are planning their projectors seem to go by the biggest image they can through up, and very few plan in advance regarding the image brightness. At the worst, they can always go in for a higher gain screen to compensate for the loss of brightness later on or change the lamp mode.

Coderguy,
Thank you for all your efforts, this is a wonderful tool my friend.

Here is a peak at the next version, it's not completed yet though:


The blue boxes (fL) next to LUMENS change automatically as you type the lumens in, even prior to generating the report. For the throw distance altering lumens, I have to decide if I should show actual lumens or baseline without modifiers. That's why fL and Lumens do not match on the form (farthest throw modifier).

I owned the Mits hc4000, and I can assure you that on an average lamp it will eventually get too dark for a 130" screen @ 1.0 gain as to how MOST people would prefer the brightness levels. I had only a 106" screen at varying gains (HP) and I had to go just one tiny notch above BEST mode in LAMP low after 400-500 hours when the screen was near 1.0 to 1.2 gain, so a 130" screen with no gain is NOT optimal if trying to conserve the lamp, but that doesn't mean it won't work at all for larger screens, it just means you'll burn through lamps faster and end up enabling BC or Sports mode or LAMP HIGH sooner. Eventually it will cost more lamps if comparing apples to apples. The Mits has reasonably priced and very reliable lamps, so you might be ok at 1.0 gain, but it's not for everyone and I'd still recommend more gain if you can.

Splitting the difference between dynamic mode and Best Mode Lamp High is one way to determine if the projector will work AT ALL for a larger screen at a given gain. So if dynamic is at 800 lumens and Best Mode High at 600, then you can figure you can probably calibrate at 700 lumens and still get a decent image (but this isn't an exact science). Keep in mind the lamps wear out faster when in Lamp high mode. Also, most of us would prefer to try to stay in best mode most of the time, so I would only pick a projector on this basis of dynamic or high best mode if your limited in your options.

I've been editing the numbers since the original 0.1 version, as some of the older numbers may have cached in your browser.

Your numbers are what I would call very marginal, for someone that isn't a real heavy PJ user (limited hours per year) or doesn't mind a darkish image, they could work, but I'd generally like to see at least 16+ fL as a start on any BEST MODE LAMP LOW number for people concerned about the image dimming over time, and a little higher doesn't usually hurt. And, there is PQ loss when losing brightness in an image, yes a dimmer image is plenty watchable but it loses a lot of POP at some point.

I figure most people using my calculator are wishing to conserve money or lamp life and to get optimal brightness over time, but I know some are not as concerned about this.

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130" Screen at Closest Throw at 1.0 Gain for hc4000
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<<Calculations for a New Lamp>>
130" Screen (Lamp Low Best Mode)= 10.4fL
130" Screen (Lamp HIGH Best Mode)= 12.5fL
130" Screen (Lamp High Dynamic Mode)= 17.1fL
130" Screen (Absolute Brightest Mode)= 23.5fL

Coderguy, thanks for the detailed reply! You are right, in that the brightness is marginal. Yesterday, I tried watching movies after increasing the gamma while keeping lamp in low mode and it definitely makes the picture pop. So, I change my earlier statement that while the basic picture is bright enough, it doesn't bring out the full "pop" of the image. I don't prefer the high lamp (due to image quality and conserving lamp life) so I guess I need to either change the gamma or change the screen gain.

The picture should look similar in lamp high once the lamp wears in, but the main issue is just that the lamp will continue to fade in brightness so if your image just passes now, then in 500 hours it will struggle. Again though, some people don't mind the dimmer images as they are not as critical, but 14 fL is the standard and I personally think this standard is about right, but the reason I tell people to go brighter than the standard is to account for lamp wear.

So since a projector can lose 15%+ brightness in 200 hours to even more, then that is why you have to be cautious, at 1000 hours of lamp life it can lose 1/3rd of the brightness or more. It varies though with operating conditions and environment, but those are general estimates.