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post #1 of 13 Old 04-24-2016, 11:25 AM - Thread Starter
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Lowest nit levels for Projectors

How do I find out the lowest nits a projector can display?

According to UHD a display has to be either of the following

Option 1: Display between 0.05 to 1000 nits
Option 2: Display between 0.0005 to 540 nits

How do I know when Option a Projector is following? With TVs is easy since only OLEDs follow option 2.
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post #2 of 13 Old 04-24-2016, 12:45 PM
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I have thought about this myself and since the projector can be used on multiple screen sizes ( from small to large) as you go bigger then would the nit value go down?
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post #3 of 13 Old 04-24-2016, 02:22 PM
 
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Quote:
Originally Posted by gowthamn View Post
How do I find out the lowest nits a projector can display?

According to UHD a display has to be either of the following

Option 1: Display between 0.05 to 1000 nits
Option 2: Display between 0.0005 to 540 nits

How do I know when Option a Projector is following? With TVs is easy since only OLEDs follow option 2.
In the projection world we don't use nits. We use foot lamberts (ftL). It should also be noted that the popular home theater front projectors, on typical screen sizes, will get NO WHERE CLOSE to 540 or 1000 nits of brightness. With that said, the best way to figure out black level is to read a professional review of a particular projector. Let's take the current JVC DLA-RS500. Cine4home measured 1680 lumens average max brightness (iris open, max zoom) and 37000:1 native contrast, with 400,000:1 dynamic contrast. As the previous poster mentioned, screen size and gain will be a factor into figuring out black level and peak white. So let's say you have a 25 square foot unity gain screen as an example. That would mean peak white is 67.2 ftL and black level is 0.0018 ftL or 0.000168 ftL when enabling the dynamic iris. If we convert this to nits you get 230.24 nits peak white and 0.00616 nits (native) and 0.0005752 nits (dynamic) for a black level.
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post #4 of 13 Old 04-24-2016, 03:06 PM
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We do use nits, or Cd/M2, the
SI unit of luminance. 100 nits being the DCi 2.0 target, 106 nits being the DC practise. BTW, ISO now also has a lumens standard, yes higher numbers thatn ANSI or Center.
Uh Seegs, you forget to mention the ambient or unwanted light this leads to a ground illumination/reflected light level.
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post #5 of 13 Old 04-25-2016, 02:27 PM - Thread Starter
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How do you calculate that the peak white and black levels from lumens and screen size?

Quote:
Originally Posted by Seegs108 View Post
In the projection world we don't use nits. We use foot lamberts (ftL). It should also be noted that the popular home theater front projectors, on typical screen sizes, will get NO WHERE CLOSE to 540 or 1000 nits of brightness. With that said, the best way to figure out black level is to read a professional review of a particular projector. Let's take the current JVC DLA-RS500. Cine4home measured 1680 lumens average max brightness (iris open, max zoom) and 37000:1 native contrast, with 400,000:1 dynamic contrast. As the previous poster mentioned, screen size and gain will be a factor into figuring out black level and peak white. So let's say you have a 25 square foot unity gain screen as an example. That would mean peak white is 67.2 ftL and black level is 0.0018 ftL or 0.000168 ftL when enabling the dynamic iris. If we convert this to nits you get 230.24 nits peak white and 0.00616 nits (native) and 0.0005752 nits (dynamic) for a black level.
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post #6 of 13 Old 04-25-2016, 02:31 PM
 
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Quote:
Originally Posted by donaldk View Post
We do use nits, or Cd/M2, the
SI unit of luminance. 100 nits being the DCi 2.0 target, 106 nits being the DC practise. BTW, ISO now also has a lumens standard, yes higher numbers thatn ANSI or Center.
Uh Seegs, you forget to mention the ambient or unwanted light this leads to a ground illumination/reflected light level.
On this forum, especially in the home theater segment, we never use nits. We always use ftL. For on/off contrast room reflection should not make a difference as far as measurements go, but of course ANSI and intra-scene contrast measurements will be greatly affected by the room and screen material being used, but that wasn't part of his question.
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post #7 of 13 Old 04-25-2016, 02:38 PM
 
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Quote:
Originally Posted by gowthamn View Post
How do you calculate that the peak white and black levels from lumens and screen size?
You take the square footage of the screen and divide by peak white lumens. Then you take the contrast number and divide your peak white foot lambert number into it to get black level. If you had a positive (or negative) gain screen you factor this in as well. One foot lambert equals 3.4262591 nits. Do your conversion. So in my example the math is:

(1680/25)(1)= 67.2ftL - Peak White

(67.2/37000)(1)=0.0018ftL - Black Level

We multiply by 1 because in this case the screen gain is 1.0. But if you had a higher gain screen you'd change the 1 to whatever the gain is.

Conversion to Nits:

67.2 x 3.4262591 = 230.24 nits

0.00622 x 3.4262591 = 0.00616 nits
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post #8 of 13 Old 04-25-2016, 05:09 PM - Thread Starter
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Projectors Don't have the range of either OLEDs or quantum dots.
Screen size is the only advantage.
Quote:
Originally Posted by Seegs108 View Post
You take the square footage of the screen and divide by peak white lumens. Then you take the contrast number and divide your peak white foot lambert number into it to get black level. If you had a positive (or negative) gain screen you factor this in as well. One foot lambert equals 3.4262591 nits. Do your conversion. So in my example the math is:

(1680/25)(1)= 67.2ftL - Peak White

(67.2/37000)(1)=0.0018ftL - Black Level

We multiply by 1 because in this case the screen gain is 1.0. But if you had a higher gain screen you'd change the 1 to whatever the gain is.

Conversion to Nits:

67.2 x 3.4262591 = 230.24 nits

0.00622 x 3.4262591 = 0.00616 nits

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post #9 of 13 Old 04-25-2016, 05:36 PM
 
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Quote:
Originally Posted by gowthamn View Post
Projectors Don't have the range of either OLEDs or quantum dots.
Screen size is the only advantage.
Who said they did? Projectors do have an advantage with WCG and contrast (with the exception being OLED). They can achieve P3 quite a bit easier than flat panels and other than OLED, most have higher contrast than flat panels.
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post #10 of 13 Old 04-25-2016, 11:43 PM - Thread Starter
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Yes, there are already projectors with BT 2020 WCG.

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Originally Posted by Seegs108 View Post
Who said they did? Projectors do have an advantage with WCG and contrast (with the exception being OLED). They can achieve P3 quite a bit easier than flat panels and other than OLED, most have higher contrast than flat panels.
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post #11 of 13 Old 04-26-2016, 03:46 AM
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Yup and that Christie demonstrator at NAB also had 1000000:1 on-off.
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post #12 of 13 Old 12-03-2019, 01:07 PM
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….so at the end of 2019 and entering 2020, this post MAY need updating. Can a 3,000 lumens projector produce 1,000 nits? What about the really high 6,000 lumens, or so, laser UST projectors??? I'm pretty sure those can start doing UHD/Dolby Vision without issue. Especially if you pony up for a Black Diamond screen to reject a lot of ambient light from affecting the image> (although many of my flat panel TV friends STILL turn off the lights when watching a popular show/movie, lol! Must be all that high gloss TV glare getting in the way of watching their movie, lmao)
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post #13 of 13 Old 12-04-2019, 01:36 PM
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Quote:
Originally Posted by PsiPr0 View Post
….so at the end of 2019 and entering 2020, this post MAY need updating. Can a 3,000 lumens projector produce 1,000 nits? What about the really high 6,000 lumens, or so, laser UST projectors??? I'm pretty sure those can start doing UHD/Dolby Vision without issue. Especially if you pony up for a Black Diamond screen to reject a lot of ambient light from affecting the image> (although many of my flat panel TV friends STILL turn off the lights when watching a popular show/movie, lol! Must be all that high gloss TV glare getting in the way of watching their movie, lmao)

I've never seen a Black Diamond in person. Does it enhance contrast so much as SI markets?
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