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JVC RS40/X3 Calibration Thread - Page 12

post #331 of 431
I updated the app to accept a screen gain, if you need that, grab it again.

Gear mentioned in this thread:

post #332 of 431
Ah right on, having a hi power screen, that is good to have.
post #333 of 431
Quote:
Originally Posted by GeerGuy View Post
I updated the app to accept a screen gain, if you need that, grab it again.
Hi,

The measurement(s) should be taken with the meter facing the projector. Therefore, screen gain shouldn't be a factor in converting lux to lumens.

Larry
post #334 of 431
Quote:
Originally Posted by Geof View Post
I think you meant screen square area, where screen area is in square meters.

for sq feet lumen = lux*screenarea/10.76
Yep, I meant m². Sorry, my mistake. I am from germany
post #335 of 431
Guys, something doesn't seem right with my calibrations.

I'm using calman and a radiance mini with an i1LT. The sensor is a few years old now.

When I try to calibrate the grey scale, it shows the RGB is way out ( although it doesn't look that bad to my eyes) If I reel them in the greys go pink, especially from about 60% and up. Although calman shows that things are tracking true.

Also in calman I only get around 9FtLBs. I realise this sensor isn't the best for measureing lumens, but even on high lamp with iris all the way open I can only get about 14FtLB. I am using a perforated screen (centerstageXD) but even on a flat white wall it doesn't change much. To me the picture is bright, but not blinding, but I would have guess it was above the minimum suggested brightness for a home theatre.

Any thoughts ? Any way of checking if my meter is playing up ? Other than testing it against a calibrated one, which I don't have access to.

My X3 is at about 100hours btw. Although when it was new I still only got about 9FtLBs.

Would a $20 light meter be good enough to compare ?
post #336 of 431
Quote:
Originally Posted by LarryChanin View Post
Hi,

The measurement(s) should be taken with the meter facing the projector. Therefore, screen gain shouldn't be a factor in converting lux to lumens.

Larry

I'm open to suggestions on when and where to apply the screen gain. My screen is 1.0, so it has never mattered.

Right now the screen gain is only applied to the fL and nits measurements, not for Lumens. I was thinking that a person would want to know the Lumens without the screen gain, since it is a measurement of the projector light output. The fL or nits values are more associated with the entire "system".

I could just make 2 columns of numbers, 1 without gain and 1 with, and apply the gain to Lumens, fL and nits.

Thoughts?

Try This:

 

Luminosity Calculator 1.1.zip 155.640625k . file
post #337 of 431
I would have thought the added gain feature in the app tells the user how many FL he is actually seeing onscreen vs how many are coming from the projector.
post #338 of 431
Quote:
Originally Posted by GeerGuy View Post

I'm open to suggestions on when and where to apply the screen gain. My screen is 1.0, so it has never mattered.

Right now the screen gain is only applied to the fL and nits measurements, not for Lumens. I was thinking that a person would want to know the Lumens without the screen gain, since it is a measurement of the projector light output. The fL or nits values are more associated with the entire "system".

I could just make 2 columns of numbers, 1 without gain and 1 with, and apply the gain to Lumens, fL and nits.

Thoughts?

Hi,

I was under the impression that the original poster wanted to calculate the lumens of the projector when lux has been measured. That does not require gain because as I have stated the measurement should have been made with the meter pointed at the projector.

If you are interested in how to calculate the foot lamberts coming off of the screen, then I suggest you take a look at Ron Jones Simple Projection Calculator.

If you want a calculator that estimates the actual screen gain based on your projector mounting location, viewer location and screen material characteristics, I suggest you take a look at forum member FLBoy's All Screen Gain calculator.

I use Ron's Lux to Lumens calculator (as discussed in posting #2) to determine my projector's lumen output. Then I use FLBoy's calculator to estimate my screen's actual delivered gain for my actual projector and viewer locations based on my screen material. Then I plug the lumens and delivered gain (not the maximum manufacturer's quoted gain) into Ron's Simple Projection Calculator to determine the foot lamberts coming off of my screen.

Larry
post #339 of 431
Quote:
Originally Posted by plissken99 View Post

I would have thought the added gain feature in the app tells the user how many FL he is actually seeing onscreen vs how many are coming from the projector.

If a user wants to know the FL from the screen, they're going to be a lot better off measuring it rather than trying to calculate it.

In theory you can measure the lumens directly from the projector and then calculate it based on your gain, but the problem is that the advertised gain and real world gain are not the same thing. So, any number you calculate based on the advertised gain is going to be misleading.

Since the user will have a meter in order to measure their projector lumens in the first place, it's going to be far better to use the same meter to measure the "real" FL from the screen.
post #340 of 431
Quote:
Originally Posted by LarryChanin View Post

I use Ron's Lux to Lumens calculator (as discussed in posting #2) to determine my projector's lumen output. Then I use FLBoy's calculator to estimate my screen's actual delivered gain for my actual projector and viewer locations based on my screen material. Then I plug the lumens and delivered gain (not the maximum manufacturer's quoted gain) into Ron's Simple Projection Calculator to determine the foot lamberts coming off of my screen.

Just curious, but wouldn't it be easier, and more accurate, to just measure the FL coming off of the screen?
post #341 of 431
Thread Starter 
Quote:
Originally Posted by wilsonj View Post

Guys, something doesn't seem right with my calibrations.

I'm using calman and a radiance mini with an i1LT. The sensor is a few years old now.

When I try to calibrate the grey scale, it shows the RGB is way out ( although it doesn't look that bad to my eyes) If I reel them in the greys go pink, especially from about 60% and up. Although calman shows that things are tracking true.

Also in calman I only get around 9FtLBs. I realise this sensor isn't the best for measureing lumens, but even on high lamp with iris all the way open I can only get about 14FtLB. I am using a perforated screen (centerstageXD) but even on a flat white wall it doesn't change much. To me the picture is bright, but not blinding, but I would have guess it was above the minimum suggested brightness for a home theatre.

Any thoughts ? Any way of checking if my meter is playing up ? Other than testing it against a calibrated one, which I don't have access to.

My X3 is at about 100hours btw. Although when it was new I still only got about 9FtLBs.

Would a $20 light meter be good enough to compare ?

The i1 Display 2 series of colorimeters (including the i1 LT) are known to have a loss of accuracy over time. Given that yours is several years old I would say that is certainly the case. X-Rite is just now releasing a new series of Colorimeters that replace the i1 Display 2 series. The new model is the i1 Display Pro III (being called i1 Display 3 by some people) and Calman will probably be offering an upgrade along with the OEM version of this new i1 model sometime soon. Note that the retail version of the "i1 Display 3" will not work with non-Xrite calibration software, such as Calman or ChromaPure (i.e., you must buy the OEM version of the i1 Display 3). The new model is said to be much more accurate and has less drift over time than the Display 2 series. The street price for the new i1 model is $269 plus Calman may charge you an upgrade fee for their software to support the new sensor, but it would probably be worth the price. The new i1 Display 3 OEM sensor in combination with Chroma Pure calibration software can be ordered thru the AV Science Store but since you already have Calman I would contact them to see what kind of upgrade they offer.

As for trying to meaure ftL off of the screen using your i1LT I have found it to be very inaccurate for that purpose. For measuring the lumens from the projector (does not involve the screen) there are low cost lux meters that work well for this purpose. See item number 5 from POST #2 of this thread.
post #342 of 431
Quote:
Originally Posted by Shagg View Post

If a user wants to know the FL from the screen, they're going to be a lot better off measuring it rather than trying to calculate it.

In theory you can measure the lumens directly from the projector and then calculate it based on your gain, but the problem is that the advertised gain and real world gain are not the same thing. So, any number you calculate based on the advertised gain is going to be misleading.

Since the user will have a meter in order to measure their projector lumens in the first place, it's going to be far better to use the same meter to measure the "real" FL from the screen.

Quote:
Originally Posted by Shagg View Post

Just curious, but wouldn't it be easier, and more accurate, to just measure the FL coming off of the screen?

Hi,

When someone is considering a new projector purchase they need to also factor in the screen characteristics. This is especially true of the RS40 in which we have to consider both 2D and 3D considerations.

In this case when we are trying to figure out the best projector/screen material combination for your configuration, it simply may not be feasible to buy multiple screens to do the measuring. I would not trust the results obtained by measuring off of those very small samples of screen material.

For folks who, for better or worse, have already committed to a projector and screen material without knowing what the foot-lamberts will be, yes measuring would be easier.

Larry
post #343 of 431
Quote:
Originally Posted by Ron Jones View Post

The i1 Display 2 series of colorimeters (including the i1 LT) are known to have a loss of accuracy over time. Given that yours is several years old I would say that is certainly the case. X-Rite is just now releasing a new series of Colorimeters that replace the i1 Display 2 series. The new model is the i1 Display Pro III (being called i1 Display 3 by some people) and Calman will probably be offering an upgrade along with the OEM version of this new i1 model sometime soon. Note that the retail version of the "i1 Display 3" will not work with non-Xrite calibration software, such as Calman or ChromaPure (i.e., you must buy the OEM version of the i1 Display 3). The new model is said to be much more accurate and has less drift over time than the Display 2 series. The street price for the new i1 model is $269 plus Calman may charge you an upgrade fee for their software to support the new sensor, but it would probably be worth the price. The new i1 Display 3 OEM sensor in combination with Chroma Pure calibration software can be ordered thru the AV Science Store but since you already have Calman I would contact them to see what kind of upgrade they offer.

As for trying to meaure ftL off of the screen using your i1LT I have found it to be very inaccurate for that purpose. For measuring the lumens from the projector (does not involve the screen) there are low cost lux meters that work well for this purpose. See item number 5 from POST #2 of this thread.

Hi Ron, thanks for your reply.

Yes I had heard about the new xrite sensor. I'll contact calman and see what is in the pipelines.

I wont waste any more time trying to calibrate the PJ with the sensor I have. I did read on here of others that had "bad" i1LTs. I probably wouldn't have picked up on it if it weren't soooo out of whack! Makes me wonder how many other people out there are trying to calibrate with an old unit that is no longer performing correctly.

Cheers
Jamie
post #344 of 431
Quote:
Originally Posted by LarryChanin View Post

Hi,

When someone is considering a new projector purchase they need to also factor in the screen characteristics. This is especially true of the RS40 in which we have to consider both 2D and 3D considerations.

In this case when we are trying to figure out the best projector/screen material combination for your configuration, it simply may not be feasible to buy multiple screens to do the measuring. I would not trust the results obtained by measuring off of those very small samples of screen material.

For folks who, for better or worse, have already committed to a projector and screen material without knowing what the foot-lamberts will be, yes measuring would be easier.

Larry

Could have been my misunderstanding, but I thought the people talking about it above already had screens.

Yes, if you don't have a screen yet you'll need to estimate it.
post #345 of 431
Thread Starter 
Quote:
Originally Posted by wilsonj View Post

Hi Ron, thanks for your reply.

Yes I had heard about the new xrite sensor. I'll contact calman and see what is in the pipelines.

I wont waste any more time trying to calibrate the PJ with the sensor I have. I did read on here of others that had "bad" i1LTs. I probably wouldn't have picked up on it if it weren't soooo out of whack! Makes me wonder how many other people out there are trying to calibrate with an old unit that is no longer performing correctly.

Cheers
Jamie

There are some companies that offer the service to recalibrate the sensor (e.g., i1 LT) for use with their specific software. The charge for such a recalibration is typically $100 or a little more. Tom Huffman at ChromaPure offers this service. I don't know if Calman offers a similar service or not.
post #346 of 431
Quote:
Originally Posted by Ron Jones View Post

I don't know if Calman offers a similar service or not.

Of course ! SpectraCal also calibrates sensors for big companies who sells TVs, beamers etc.
post #347 of 431
Quote:
Originally Posted by plissken99 View Post

Can someone give a few more details on using the lux meter? 1, should I be using it on a 100ire test pattern screen or something?

Also is there some other way to convert lux into lumens? Because that spread sheet tell me nothing, I can't edit it in any way either since I don't own Excel.

Quote:
Originally Posted by GeerGuy View Post

I made a Window's program that will convert from measured lux to lumens, fL and nits for a given screen size.

Quote:
Originally Posted by GeerGuy View Post

I updated the app to accept a screen gain, if you need that, grab it again.

Quote:
Originally Posted by LarryChanin View Post

Hi,

The measurement(s) should be taken with the meter facing the projector. Therefore, screen gain shouldn't be a factor in converting lux to lumens.

Larry

Quote:
Originally Posted by Shagg View Post

Could have been my misunderstanding, but I thought the people talking about it above already had screens.

Yes, if you don't have a screen yet you'll need to estimate it.

Hi,

As you can see from the above quoted postings, the original discussion started with the original poster asking how to calculate lumens of the projector. As you know that involves taking measurements with the meter facing the projector. Therefore, in the original context whether or not he already has a screen is irrelevant.

Yes, with the conversation switching to luminance the option to turn the meter around and measure the reflections off of an existing screen presents itself, but perhaps a Colorimeter would be a better tool for this since measuring foot-lamberts is one of its primary functions.

Larry
post #348 of 431
Pardon the sloppy quote (cut & paste really). Previous 2 measurements I posted here"

----


- Hours: 752
- Delivery: Dec 8th 2010
- Screen size: 128"
- Throw lens/screen: 14' give or take a few inches...
- Natural mode
- Color space: normal
- Gamma normal
- High Lamp
- Iris fully open (0)
The reading at center screen shows 115 lux or 519 Lumens.

---------

- Hours: 995
- Same settings described above
- Took my measurement upon startup (no warm-up time)
- Using Lumangen mini - user setting 4 [means nothing to you guys but it's just for my reference down the line]


Center screen is showing 85.9 lux or 388 Lumens. A 34% drop in 250 hours. It caught me offguard. Gotta be honest, I'm still using Normal lamp with aperture at -7 although I'm probably opening it to -5 later tonight. I'm still very happy and my brain is certainly not registering a 34% drop.


-----------



So the latest reading is as follow:

- Same settings as above
- Hours: 1163

Center screen is showing 53 lux or 239 Lumens.

I do my regular viewing on normal lamp with iris fully open. For a while the picture quality was bugging me. So now last night at 1178 hours watching the Indiana Jones DVD I came to the conclusion that the image was too dim to appreciate this fine projector. I broke down and switched to high lamp with aperture at 12. I have a feeling the iris will get open wider sooner than I did on low lamp. But for now the PQ is back to "WOW".

So extrapolating a bit here, if I enjoyed the pic up until 1100 hrs (approx.) is it fair to assume that I could enjoy another 500 hours in high lamp mode? Time will tell. That would bring me to 1600/1700 hours. Under the 2000 hours I was hoping for but none the less not so bad.

One thing is for sure, I'm contacting Mark Haflich in the next few days to order a replacement lamp. I want one on hand for when the time comes.
post #349 of 431
Quote:
Originally Posted by zbroke View Post

Pardon the sloppy quote (cut & paste really). Previous 2 measurements I posted here"

----


- Hours: 752
- Delivery: Dec 8th 2010
- Screen size: 128"
- Throw lens/screen: 14' give or take a few inches...
- Natural mode
- Color space: normal
- Gamma normal
- High Lamp
- Iris fully open (0)
The reading at center screen shows 115 lux or 519 Lumens.

---------

- Hours: 995
- Same settings described above
- Took my measurement upon startup (no warm-up time)
- Using Lumangen mini - user setting 4 [means nothing to you guys but it's just for my reference down the line]


Center screen is showing 85.9 lux or 388 Lumens. A 34% drop in 250 hours. It caught me offguard. Gotta be honest, I'm still using Normal lamp with aperture at -7 although I'm probably opening it to -5 later tonight. I'm still very happy and my brain is certainly not registering a 34% drop.


-----------



So the latest reading is as follow:

- Same settings as above
- Hours: 1163

Center screen is showing 53 lux or 239 Lumens.

I do my regular viewing on normal lamp with iris fully open. For a while the picture quality was bugging me. So now last night at 1178 hours watching the Indiana Jones DVD I came to the conclusion that the image was too dim to appreciate this fine projector. I broke down and switched to high lamp with aperture at 12. I have a feeling the iris will get open wider sooner than I did on low lamp. But for now the PQ is back to "WOW".

So extrapolating a bit here, if I enjoyed the pic up until 1100 hrs (approx.) is it fair to assume that I could enjoy another 500 hours in high lamp mode? Time will tell. That would bring me to 1600/1700 hours. Under the 2000 hours I was hoping for but none the less not so bad.

One thing is for sure, I'm contacting Mark Haflich in the next few days to order a replacement lamp. I want one on hand for when the time comes.

Hi,

Thanks for your reports. They are very helpful.

With such low measurements am I correct that you are not doing any 3D viewing?

Thanks.

Larry
post #350 of 431
Quote:
Originally Posted by LarryChanin View Post

Hi,

Thanks for your reports. They are very helpful.

With such low measurements am I correct that you are not doing any 3D viewing?

Thanks.

Larry

I haven't bought a 3D title in a while so no I'm not watching 3D. I imagine the picture would be too dim to really enjoy it but if a 3D movie I really want to see would come out, I would probably buy and watch it just the same and suffer through it.
post #351 of 431
Quote:
Originally Posted by zbroke View Post

I haven't bought a 3D title in a while so no I'm not watching 3D. I imagine the picture would be too dim to really enjoy it but if a 3D movie I really want to see would come out, I would probably buy and watch it just the same and suffer through it.

Hi,

Thanks for the response.

With regard to your remark:

Quote:
[...]I'm contacting Mark Haflich in the next few days to order a replacement lamp. I want one on hand for when the time comes.

It seems to me the time has come. It probably is unwise to wait for the lamp to fail, and risk an exploding lamp when the functionality of your projector is already seriously compromised.

Thanks again for the reports.

Larry
post #352 of 431
Thread Starter 
Zbroke - The industry standard for the bulb life is when the bulb light output drops 50%. It appears your bulb reached that point at near 1000 hours. I take it the bulb was kept in normal (i.e., low) lamp mode for most viewing meaning the actual bulb life was 1/3 the JVC rating of 3000 hr. for normal lamp mode or even 1/2 the JVC rating for high lamp mode.
post #353 of 431
Quote:
Originally Posted by Ron Jones View Post

Zbroke - The industry standard for the bulb life is when the bulb light output drops 50%. It appears your bulb reached that point at near 1000 hours. I take it the bulb was kept in normal (i.e., low) lamp mode for most viewing meaning the actual bulb life was 1/3 the JVC rating of 3000 hr. for normal lamp mode or even 1/2 the JVC rating for high lamp mode.

Hi Ron,

Can you please explain how you estimated the half-brightness point occurred at near 1000 hours?

Zbroke wasn't able to measure his output at zero hours, so how do we figure out where the half-point is?

Thanks.

Larry
post #354 of 431
Thread Starter 
Quote:
Originally Posted by LarryChanin View Post

Hi Ron,

Can you please explain how you estimated the half-brightness point occurred at near 1000 hours?

Zbroke wasn't able to measure his output at zero hours, so how do we figure out where the half-point is?

Thanks.

Larry

I just assumed as a starting point that his projector's lumens were in the same range as several of us have measured on our RS40's when new or with very few hours on the bulb. For a single center screen measurement with the projector near max. zoom (he has fairly short throw at 14' for a 128" screen), iris fully open, natural picture mode, etc., it appears the typical new RS40 will have somewhere around 900 lumens. Mine measured a little more some owners have measured a little less. So even if his RS40 started out when new at the low end of the range (e.g., 800 lumens) then the half output point would be at 400 lumens. He measured 388 lumens at 995 hours. In reality his projector probably reached the 50% at somewhat lower hours.
post #355 of 431
Quote:
Originally Posted by Ron Jones View Post

I just assumed as a starting point that his projector's lumens were in the same range as several of us have measured on our RS40's when new or with very few hours on the bulb. For a single center screen measurement with the projector near max. zoom (he has fairly short throw at 14' for a 128" screen), iris fully open, natural picture mode, etc., it appears the typical new RS40 will have somewhere around 900 lumens. Mine measured a little more some owners have measured a little less. So even if his RS40 started out when new at the low end of the range (e.g., 800 lumens) then the half output point would be at 400 lumens. He measured 388 lumens at 995 hours. In reality his projector probably reached the 50% at somewhat lower hours.

Hi Ron,

Thanks.

Larry
post #356 of 431
Quote:
Originally Posted by Ron Jones View Post

Zbroke - The industry standard for the bulb life is when the bulb light output drops 50%. It appears your bulb reached that point at near 1000 hours. I take it the bulb was kept in normal (i.e., low) lamp mode for most viewing meaning the actual bulb life was 1/3 the JVC rating of 3000 hr. for normal lamp mode or even 1/2 the JVC rating for high lamp mode.

Industry standard as in time to change the bulb even if it throws a good image?

I did in deed watch in normal lamp mode. Aprox ten 45 minute documentaries and maybe ten movies at most were watched in 3D mode (high lamp).

So if it is time to change the lamp due to safety this changes things. Maybe a call to my dealer and/or JVC but after 8 months and 1200 hours I don't think I will get much luck...

I will sleep on it.
post #357 of 431
In this Thread...http://www.avsforum.com/avs-vb/showt......they're now talking about cleaning the Prism in front of the lamp and a lot of people are seeing measurable improvements in Fl .

...and the Instructions..........http://www.avsforum.com/avs-vb/showt...0#post19405330

Scott....................
post #358 of 431
Thread Starter 
Quote:
Originally Posted by zbroke View Post

Industry standard as in time to change the bulb even if it throws a good image? .......

The industry standard of a 50% drop in light output that I referred to is for how a manufacture is supposed to rate the lifetime of a lamp. Clearly you may find that even at 1/3 of the original brightness it is still acceptable to you.
post #359 of 431
Quote:
Originally Posted by Scott_R_K View Post

In this Thread...http://www.avsforum.com/avs-vb/showt......they're now talking about cleaning the Prism in front of the lamp and a lot of people are seeing measurable improvements in Fl .

...and the Instructions..........http://www.avsforum.com/avs-vb/showt...0#post19405330

Scott....................

Hi Scott,

I thought that problem was confined to the earlier JVC lamps and was due to some sort of off-gassing of the lamp housing, and that later replacement lamps didn't suffer from this problem.

Quote:
Originally Posted by Steve Smith View Post

I have an RS20 with about 1600 hours on it and have cleaned it every 300-400 hours. At 1200 hours I decided the lamp was getting too dim for my large screen and bought a new OEM lamp. I now have about 400 hours on the new lamp. When I went to clean it there was no film or haze buildup. This leads me to believe that it was something in the original lamp housing that was offgassing. The original lamp also had the film buildup on the inside of the glass that's on front of the lamp housing.


Do you have any information that this problem is occurring on the new generation of JVC 3D projectors?

Thanks.

Larry
post #360 of 431
Quote:
Originally Posted by LarryChanin View Post

I thought that problem was confined to the earlier JVC lamps and was due to some sort of off-gassing of the lamp housing, and that later replacement lamps didn't suffer from this problem.

My memory agrees with yours. Pretty sure I've read on here before that the above problem/fix applies to the older generation RS models, but not the current RS40/50/60.
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