Using the CA813 light meter to measure your front projector - AVS Forum
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post #1 of 111 Old 11-23-2006, 09:35 AM - Thread Starter
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I've had a lot of questions recently about using a light meter to measure lumens, ftL, on/off CR and ANSI CR so I'm putting together this basic tutorial. I hope others with experience will chime in and add their tips and techniques that have worked great for them as well.

Note that the following is a depiction of how I use the meter and what works for me. Others techniques I'm sure can be used as well, which may even be better. So don't take this information as definitive, but rather just to give you some ideas. I'm rather new to this meter so it would be great to hear the feedback from others.

Also I'll talk about specific measurements I got with my Ruby at 525 hours on the bulb and using near max throw. For reference I have a 106" diag Firehawk with 1.3 gain.

OK, let's get started...

What is the AEMC CA813?
The AEMC CA813 is a light meter that can be used to measure light output from your pj in foot candles (fc) and lux. It is a popular light meter among AVSers because it is accurate, inexpensive (about $165), and convenient to use.

Using the meter to measure lumens
Set the meter to measure in lux with one decimal point of precision. Display a 100 IRE full field pattern. Ideally your pj should be first calibrated to D65. However this is not necessary if you want to know what the max light output is that your pj is capable of regardless of its calibration.

Stand AT THE SCREEN and rest the back of the sensor gently on your screen (or hold it just in front of it), facing the pj lens. You could use a tripod but doing so doesn't allow you to measure exactly at the screen which I prefer.

Because it is a bright reading the number should dial in within a few seconds. Hold the meter still for best results. If it shows 0 and you have a very bright pj try removing the decimal point percision, or you can also measure in fc instead.

In my case I measured 62.3 lux. However to determine lumens you must now factor in the size of the screen. At first I was confused by this. I thought to myself "What does the screen size have to do with anything since I am measuring the light directly from the pj and not off the screen?".

Well the answer of course is that the lens zoom and focus changes the intensity of the light. So as you zoom out and throw a larger picture, the intensity of the light goes down, and vice-versa. The lumen measurement is designed in such a way that, although the screen size factors into the measurement, it provides a result which can be compared apples-to-apples with anyone else's lumens measurements regardless of their screen size (assuming they measured correctly).

OK, next we convert our lux or fc measurement to lumens. The formulas for this are:

lumens = (lux / 10.76) * square feet of screen in FEET (not inches)

or

lumens = fc * square feet of screen

So in my case my 106" diag FH is 33.22 sq. feet. So I had (62.3 / 10.76) * 33.22 which comes out to 192.4 lumens.

Converting lumens to ftL

To convert your lumens to ftL use this formula:
ftL = lumens * screen gain / (area of screen in sq. feet not inches)

So in my case I was getting 192.4 * 1.3 gain / 33.22 = 7.53ftL

Just a side note: I considered the picture I was getting from my Ruby to be quite bright and punchy, so I was SHOCKED to determine I was only getting 7.5ftL. This taught me an important lesson, because previously I was under the impression that I "had to have" at least 12 ftL to be satisfied. Your preference may be different so you really need to get a sense for yourself what is acceptable. It may also have been the super high 20,200:1 CR I was getting that helped the perceived brightness to be much higher than I would have thought.

How to measure ON/OFF CR
Unlike the previous measurement for lumens, the measurement for on/off CR should be done very close to the pj lens - say about 12-18 inches. This is because the AEMC will not give you sufficient accuracy at the screen with a 0 IRE measurement, especially if your pj has excellent black levels.

The key here is that you do NOT move the zoom or focus of the pjs lens when taking this measurement. Just move your meter up to the front of the lens. You will also need a tripod for this to get an accurate black level reading. Although it can be done without one, it grows tiring trying to keep the sensor stable enough to get an accurate reading otherwise.

So with your meter now just in front of the pj lens using a tripod, set the meter to measure lux with two decimal points of precision. Display a 0 IRE full field pattern. It will take a while for the sensor to adjust. You'll likely see an initial high reading, and then the meter will start dropping off. Give it some time - it can take up to a minute or two. Eventually it will stop dropping and at that point you have your reading.

In my case for 0 IRE I measured 0.16 lux. [Side note: You cannot compare this black level by itself to that of your own, as it is dependent on many factors such as the distance to the lens and zoom/focus position. ]

Next change to a 100 IRE full field pattern. For this you must switch the meter to measure in fc because it will be very high when measured at the pj (much more so then when measured at the screen previously).

Also important is that you measure the 100 IRE pattern at the same exact position as the 0 IRE pattern. This is why using a tripod is so important.

For my 100 IRE pattern I measured 300 fc. To calculate my contrast ratio I just need to convert the fc to lux. To convert fc to lux just multiply the fc by 10.76391. So in my case 300 fc = 3229.173 lux.

To calculate the on/off CR, simply divide the two. In my case:
3229.173 from 100 IRE measurement / 0.16 from 0 IRE measurement = 20182:1

(In case you are wondering, I am using Darin's iris tweaks for the Ruby which yields substantially greater on/off CR than otherwise out of the box).

How to measure ANSI CR
First just a note - I think technically to measure true "ANSI" CR one must make a number of measurements from various parts of the screen and do averages or something along those lines. I do not do this as I think others do not as well. So its important to note that I do not believe the technique I am explaining here measures real ANSI CR but gives you a comparable measurement.

ANSI CR can be measured both at the pj and at the screen. This is because the 0 IRE block in the checkerboard will be a lot higher than a full 0 IRE pattern which enables you to get a good reading at the screen. Reading at the screen is also important as it takes room reflections and any ambient light into account for what you are actually getting at the screen.

Now onto our measurements. Put up the first checkerboard pattern. Put the tripod in front of the pj, similarly to how you did for the on/off measurement. Except this time you want to move the tripod so the sensor is off center of the screen, and instead it should be centered with a black box on the checkerboard pattern. I use the first black box off center. So look back at the screen and position the sensor so that the shadow from the sensor thrown on the screen is centered in that black box.

With the sensor position, take a reading in lux and note it. Now move to the next checkerboard pattern so the sensor is then centered in a 100 IRE white box. You will likely need to read this in fc. Convert this to lux and note this value. Divide the two. The result is your ANSI CR measurement at the pj. In my case I had:
3864.2 from the 100 IRE checkerbox / 37.5 from the 0 IRE checkerbox = 103 ANSI CR at the pj.

Now, repeat this same process, except measure this AT THE SCREEN. Your ANSI will go down, unless you have a perfect bat cave. In my case my ANSI CR at the screen was 70.9 lux / 0.84 lux = 84.4 ANSI CR at the screen.

An interesting expiriment, which I will soon be doing, it to cover up reflective areas of the room and repeat the ANSI CR measurements at the screen to see how things improve.

As a side note - the AEMC does not come with a tripod mount and I don't think one is available. I made a makeshift one very easily which makes taking the 0 IRE measurements much easier. For this I cut a block of wood so that it fits tightly within the top of the tripod mount (insert in its tray). I then drilled two holes in the top that were just big enough to have the two prongs on the sensor fit in snugly. I then covered the whole thing in black felt.

I then also made a black square of felt and cut a hole in the middle just big enough to fit over the black ring which contains the sensor itself. This blocks the light that would otherwise be reflected back at the pj lens and then back into the meter because otherwise that area is a bright yellow plastic that is highly reflective (surprising they wouldn't have at least made this black). Total time about a half hour.

I know I mentioned it here quite a bit, but again I want to stress the importance of using a tripod mount for all these measurements.

Please feel free to ask any questions and post your own experiences and techniques you use in performing these measurements.

For related reading about determining whether a certain screen type and size will work with a projector you are considering, see Bob's excellent thread "Will this projector/screen work in my room? - A tutorial" here: http://www.avsforum.com/avs-vb/showthread.php?t=753497
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post #2 of 111 Old 11-23-2006, 10:12 AM
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Nice! Thanks for taking the time to put this together. If everyone had a light meter and took some readings it will no doubt dispel a lot of myths on this forum about true ft-Lamberts and required lumens.

Also, re" An interesting expiriment, which I will soon be doing, it to cover up reflective areas of the room and repeat the ANSI CR measurements at the screen to see how things improve."

I'll be interested in hearing how this works out. My HT is dark to begin with (black ceiling and black sidewalls near the screen transitioning to burgundy). Even with this setup I'm sure my ANSI is getting washed out. The RS1 should be somewhere around 300-350:1 ANSI CR but I don't think I'll get close to this off the screen because of light reflections. I'm thinking of repainting my HT and going with a true black cave except for the carpet.

I'd also love to see a comparison of measured ANSI (off the screen) between a normal and high ft-lambert (high gain) setup. I think some people might be surprised at the level of real world contrast is lost with a high ft-L setup. I have a High Power and a ST130 so maybe I'll do this when I get a chance and post some numbers.
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post #3 of 111 Old 11-23-2006, 10:17 AM
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Great thread and very helpful/udeful for snyone wanting to know what kind of ANSI performance either thor room or projector will allow.

I found adding some black felt material to the walls and ceiling up to just 6ft from the screen increased my ANSI significantly. Initially my screen was touching the sloping ceiling of my loft room, and with the walls being 18% grey paint, the light reflection was significantly reducing my ANSI. Moving the screen down (and away from the walls) when I went to a scope screen increased the ANSI by 30%. Adding the felt to the walls increased the figure by a further 30%.

I also found that the speakers near the screen were effecting some fo the readings at the lower parts of the screen, so that reduced the overall average number. By covering those up with black felt increased the lower readings so they matched the upper readinsg and gave another big increase in ANSI. By blacking 80% of the screen out using some left over felt (not enough to cover it 100%) I found that the pj was giving around 400:1 ANSI. A full blackout of the screen would have given even more. Currently then my room is the limiting factor as I am currently getting around 200:1 max. I need to cover all the walls and ceiling for optimum results.

Gary

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post #4 of 111 Old 11-23-2006, 10:17 AM
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Very useful information. I'm sure a lot of people will benefit from this. Let me add a couple of things.

1. The AEMC meter has 3 buttons above the on/off switch. The middle button turns the illumination in the readout on and off. You will probably need to have this on to read the measurement of black. Make sure it's behind the sensor so it doesn't contaminate the reading. The left button adjusts the range of the readings. You'll need to adjust this downwards during the black reading so you can get an accurate number with decimals.

2. When taking ANSI contrast readings, you can use the checkerboard patterns from Avia that simply shift the black and white checkerboards. This way you don't have to move the tripod between readings.

3. Taking the ANSI contrast readings close to the lens should be an accurate measurement of the PJ's true ANSI CR. When taking the readings at the screen, the light from the white squares bounces off reflective surfaces in the room and washes out the black squares. In the nearfield, the black squares are already greatly elevated in brightness so they are much less susceptible to this.

4. I was able to double the at-screen ANSI CR reading in my room (100 to 200) by painting the screen housing black and placing black velvet on the ceiling directly in front of the screen extending out about 4 feet. It really does work.

5. I am somewhat amused that you have been agonizing over whether the Z20000 would have enough light output for you considering that you are getting only 7.5fL right now from the Ruby.

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post #5 of 111 Old 11-23-2006, 10:34 AM
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After using two colour correcting filters on my HT1000 to get as much CR as I could out of it, I was surprised to find I was getting just 4FL. Until then I'd thought that number would be unwatchable. As it was, it looked just fine. CRT owners probably live with numbers like that all the time, but with such high CR, it's probably what makes the image look brighter (as the blacks are so much blacker)

I prefer around 9FL with DLP to mute image noise etc (the higher you go, the more the image can look noisy IMHO), so 7.5 will be fine for me. 12FL was OK, but after the lamp dims it looks more filmlike (IMHO) despite being DLP.

Gary

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post #6 of 111 Old 11-23-2006, 11:15 AM - Thread Starter
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Quote:
Originally Posted by Mark Petersen View Post

Nice! Thanks for taking the time to put this together. If everyone had a light meter and took some readings it will no doubt dispel a lot myths on this forum about ft-Lamberts and required lumens.

Agree 100%. I think many people will be surprised at how bright 7-8ftL looks with a super high CR pj in a light controlled room.

Quote:


Also, re" An interesting expiriment, which I will soon be doing, it to cover up reflective areas of the room and repeat the ANSI CR measurements at the screen to see how things improve."

In my case I think most of the light is coming from the light reflected off the screen, to the back wall, and then back onto the screen. So I will try covering up the back wall with some material and remeasure. My walls are already a medium-dark green and due to WAF I'm not going to get much better in that regard. However if I can come up with even a temporary solution like hanging material across the back wall just when sitting down to do some serious viewing and then removing it, so be it!

Also my carpet is quite light and I suspect that is casting quite a bit of light back into the room. So I'll try covering that up separately and see how that impacts the measurements.

That's whats so great about the CA813 is that its makes it so easy to experiment with your room and get direct feedback on what type of impact the changes are making.
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post #7 of 111 Old 11-23-2006, 11:21 AM - Thread Starter
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As a side note, I thought some of you may be interested in this comparision between my Ruby and old Sharp 10K. With both projectors calibrated @ D5:

Ruby: ANSI CR at pj: 103:1, ANSI CR at screen: 84:1, on/off: 20200:1

Sharp 10: ANSI CR at pj: 279:1, ANSI CR at screen: 100:1, on/off: 1320:1

Although the Ruby of course blows away the Sharp 10K in many respects, it is interesting to see DLP's distinct advantage in ANSI CR even when comparing LCoS to DLP technology that's 3 years old. If the specs on the JVC turn out to indeed be 300:1 or more on ANSI CR that would be a nice improvement. Of course as we've been talking about here, much work is needed to control room reflections to get the maximum benefits of such improvements.
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post #8 of 111 Old 11-23-2006, 11:29 AM - Thread Starter
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Quote:
Originally Posted by TomHuffman View Post

4. I was able to double the at-screen ANSI CR reading in my room (100 to 200) by painting the screen housing black and placing black velvet on the ceiling directly in front of the screen extending out about 4 feet. It really does work.

Hi Tom - thanks for the great input. How did you secure the black velvet to the ceiling? Do you think black felt would be equally effective? Wow, 200:1 ANSI CR at the screen is indeed excellent by all accounts - nice work!

Quote:



5. I am somewhat amused that you have been agonizing over whether the Z20000 would have enough light output for you considering that you are getting only 7.5fL right now from the Ruby.

Yes indeed. I was quite surprised myself as I've said. Having the CA813 has completely redefined my standards for what is acceptable ftL because I KNOW what brightness actually looks like at these levels, vs. just having to go by recommended standards.

Based on my research I have concluded that indeed the Sharp 20K would work well for me. Based on your report of 344 lumens in high lamp / high contrast mode (which is the only mode I'd use) I'd start out at about 13.5ftL which would be great. Then assuming I lost half the brightness at about 600-800 hours I'd be where I am now which is acceptable and just change the bulb once a year.

It it wasn't for the 20K's several thousand dollars more street price, it would be hanging on my ceiling already. I still haven't completely ruled it out. However if the JVC specs how out to be true, it'll likely deliver similar (or better) on/off CR while providing twice the brightness and for much less $. I love the sharpness of DLP however... trade offs, trade offs...
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post #9 of 111 Old 11-23-2006, 12:06 PM
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Lovingdvd: Any idea how to use the CA813 to measure ftL from an RPTV? I'm on the preorder list for a RS1 (will be my first FP) but now have a 73" Mits 1080p RPTV, and it would be very useful to know what ftL I'm getting from it. And thanks for this thread; I have a CA813 I've played around with, but having your 'walk through' is very nice!
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post #10 of 111 Old 11-23-2006, 12:25 PM - Thread Starter
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Quote:
Originally Posted by millerwill View Post

Lovingdvd: Any idea how to use the CA813 to measure ftL from an RPTV? I'm on the preorder list for a RS1 (will be my first FP) but now have a 73" Mits 1080p RPTV, and it would be very useful to know what ftL I'm getting from it. And thanks for this thread; I have a CA813 I've played around with, but having your 'walk through' is very nice!

That's a great question. I don't want to get too off topic since this is specific for front pjs and posted in the front pj forums. But I suppose you do the same except you put the sensor right up to the screen or close to it.

Before you even go that route however, I can tell you this is not a great idea... Your RPTV will be throwing a ftL measurement which is "off the charts" higher compared to what you'll get from a front pj and its not really even a fair comparison. What I'd recommend instead is going to a HT store and looking at those pjs and measure their lumens and ftL. That will give you a much better idea.
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post #11 of 111 Old 11-23-2006, 01:48 PM
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Happy Thanksgiving! While I wait for the turkey to cook, here is a tip on measuring "ANSI-like" contrast.

Be sure you measure the "black" and white values using EXACTLY the same sensor position and angle, i.e. mount the sensor on a tripod. Do not take a "black" reading on one square of the checkerboard and a white reading on another. That will introduce large errors. If you don't have both a checkerboard pattern and an inverse checkerboard pattern, you can simply use the projector orientation controls to electronically switch the checkerboard square from black to white while leaving the sensor at the same position. Another tip is to cover the screen with a large piece of black felt while making the measurement, or alternatively block the light from reaching the screen by placing a considerably smaller piece of black felt behind the sensor (when making measurements close to the projector - which you should do to measure the performance of the projector rather than the projector + room). There are all kinds of other things you can do to keep reflected light from reaching the sensor, but just blocking the light from reaching the screen will provide the largest single improvement.

I also suggest that you use my "modified ANSI" measurement, which isn't much more difficult than what was suggested at the top of this thread. It will give you a better representation of the performance, and you can also compare your results directly to the numbers in my reviews. Measure the contrast ratio (white value/black value) for EACH of the 4 squares in the MIDDLE of a 4x4 checkerboard, and then average the 4 contrast ratio measurements. If you use a checkerboard other than 4x4 you will get a much different value.

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post #12 of 111 Old 11-23-2006, 02:10 PM
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Excellent writeup, Ric! With information like this I feel sure that a lot of people will want to buy one of these meters and track their lamps, find out how bright their picture really is, and will generally gain a greater understanding of what all these numbers mean to them in real life.

The CA813 really is a very nice, easy to use, and cost effective meter, and provides a wonderful means of taking measurements. I will caution people, though, not to interpret the readings as absolute measurements, as these meters are not the super expensive, NIST calibrated meters that are used for reference, and as such are only accurate within about 10% (IIRC) of reference. They will measure repeatedly and consistently, though, so they are a great way of keeping track of relative measurements within your own system.

I also have a couple of other formulae that might be of use:

For converting lux directly to ftL:

ftL = lux * screen gain / 10.76

And for our brethren using the metric system, to convert lux to lumens:

lumens = lux * square meters of screen

Oh, and thanks for the plug...

Great stuff! This thread will be linked from mine as well...
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post #13 of 111 Old 11-23-2006, 03:05 PM
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Quote:


How did you secure the black velvet to the ceiling? Do you think black felt would be equally effective?

I wrapped the fabric around a panel of lightweight insulation and then glued it to the back of the panel using contact cement, which has an unfortunate tendency to melt the insulation. I then attached it to the ceiling using dry wall screws.

It's a very cheap and simple upgrade that took little more than an hour to complete. Black felt would be fine.

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post #14 of 111 Old 11-23-2006, 08:39 PM
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Thanks very much for putting together this thread. I am printing out all this valuable information.

Phil
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post #15 of 111 Old 11-27-2006, 08:18 AM - Thread Starter
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As a follow up to my previous posts - I had a chance last night to try various experiments in the room to improve ANSI CR. See http://www.avsforum.com/avs-vb/showthread.php?t=757920 for details on what I found. Thanks.
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post #16 of 111 Old 11-27-2006, 09:55 PM - Thread Starter
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BTW I should also add that its a good idea to wear dark clothing, particularly a black shirt. After taking readings in consecutive nights I found that my black level readings with the ANSI CR pattern were 0.04 lux lower with the black shirt since I was holding the meter at the screen. At a glance that may not seem like a lot but it actually affects the ANSI CR reading pretty significantly.
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post #17 of 111 Old 01-13-2007, 11:32 AM
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Wow !! Thanks !!

Where can I buy this sucker ??
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post #18 of 111 Old 01-13-2007, 11:43 AM - Thread Starter
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Quote:
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Wow !! Thanks !!

Where can I buy this sucker ??

I can't recall where I got mine but a Google search will turn up options (this is what I did).
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post #19 of 111 Old 01-13-2007, 12:16 PM
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Thank you.... Looks like the 811 is the same thing and about $40 cheaper.
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post #20 of 111 Old 01-14-2007, 09:53 AM
 
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Quote:
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Thank you.... Looks like the 811 is the same thing and about $40 cheaper.

The 811 has a Max function and the 813 has a Peak function. I don't know what this is. Will the 811 be just as accurate for taking the above measurements?

Never mind, I did a bit more searching and it looks like the 813 is the one to get. I just ordered it. Thanks
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post #21 of 111 Old 02-23-2007, 05:31 AM
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Cool, I'll also try try 813 then.

Thx guys !!
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post #22 of 111 Old 02-23-2007, 05:54 AM
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Dark clothing, dark gloves, and a black ski mask. If you get too hot wearing the ski mask, black grease paint works well. I looked for a black lab coat but coudn't find one.

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post #23 of 111 Old 03-04-2007, 12:09 PM
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Quote:
Originally Posted by gregr View Post

Happy Thanksgiving! While I wait for the turkey to cook, here is a tip on measuring "ANSI-like" contrast.

Be sure you measure the "black" and white values using EXACTLY the same sensor position and angle, i.e. mount the sensor on a tripod. Do not take a "black" reading on one square of the checkerboard and a white reading on another. That will introduce large errors. If you don't have both a checkerboard pattern and an inverse checkerboard pattern, you can simply use the projector orientation controls to electronically switch the checkerboard square from black to white while leaving the sensor at the same position. Another tip is to cover the screen with a large piece of black felt while making the measurement, or alternatively block the light from reaching the screen by placing a considerably smaller piece of black felt behind the sensor (when making measurements close to the projector - which you should do to measure the performance of the projector rather than the projector + room). There are all kinds of other things you can do to keep reflected light from reaching the sensor, but just blocking the light from reaching the screen will provide the largest single improvement.

I also suggest that you use my "modified ANSI" measurement, which isn't much more difficult than what was suggested at the top of this thread. It will give you a better representation of the performance, and you can also compare your results directly to the numbers in my reviews. Measure the contrast ratio (white value/black value) for EACH of the 4 squares in the MIDDLE of a 4x4 checkerboard, and then average the 4 contrast ratio measurements. If you use a checkerboard other than 4x4 you will get a much different value.

Greg,

Which test disk puts out a 4 by 4 Ansi pattern. I have the Avia Guide but all it puts out is a 20 or greater checker board pattern over the whole screen
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post #24 of 111 Old 03-13-2007, 06:50 PM
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Wow, what a great thread! Certainly deserving of a "bump"!

I have my meter coming (thanks Bulldogger!).
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post #25 of 111 Old 03-13-2007, 10:33 PM
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Im ma gonna get me a THD meter from audionerd and measah the THD and IMD of my RS1. Anybody know the spec? I assed them and instea of anserin me they assed me if I was Ric. Heh heh, I sahd nah, I wz Rob! Ya can take it to da banc that if it be over da spec by more than .01 Im ma goin to send the RS1 back!

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post #26 of 111 Old 03-14-2007, 10:47 AM
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Buying a CA813 light meter was one of the best investments I've made. I was startled to know the foot lamberts I was getting from my H79 were so low when the picture looked plenty bright. And with my dVision having a light meter is a must. Thanks for posting this thread - invaluable information here!!

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post #27 of 111 Old 03-14-2007, 11:10 AM
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Originally Posted by lovingdvd View Post

I've had a lot of questions recently about using a light meter to measure lumens, ftL, on/off CR and ANSI CR so I'm putting together this basic tutorial.

Thank you so much for this!

Please, feel free to call me by my first name, Petri.
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post #28 of 111 Old 03-14-2007, 12:19 PM
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Thanks for the great info! I just ordered a meter. Any advice on getting the tripod up to the lens of a ceiling mounted projector?
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post #29 of 111 Old 03-14-2007, 12:21 PM - Thread Starter
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My pleasure guys.

One thing I would add is that when taking the on/off measurements at the lens - care should be taken to minimize any reflected light. This can be done one of two ways, and preferably both.

One - if your pj is ceiling mounted, temporarily put some black material on the ceiling especially if it is just a few inches away from the lens. With my RS1 the lens is no more than 6 inches from the ceiling, so some light at 0 IRE still goes up to the ceiling and makes it back to the probe. Just the slightest amount of stray light can skew the on/off results considerably.

Second - create a "light trap" behind the tripod mounted meter to prevent light from researching the screen, thereby minimizing the stray light that could make it back to the meter. I do this by holding a large black piece of velvet behind the tripod and checking the screen to make sure its blocking all light from reaching the screen.
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post #30 of 111 Old 03-14-2007, 12:22 PM
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Quote:
Originally Posted by mlang46 View Post

Greg,

Which test disk puts out a 4 by 4 Ansi pattern. I have the Avia Guide but all it puts out is a 20 or greater checker board pattern over the whole screen

Mine does. Both. And the offical ANSI probe locations. See sig.
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