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The bulb/lamp light on my unit just turned orange today. The projector is around 3500hrs. I've only used it on low mode, so I thought I had another 1000 hours to go. Should I change the bulb immediately, or do I have more time? The picture still looks fine.
 

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The bulb/lamp light on my unit just turned orange today. The projector is around 3500hrs. I've only used it on low mode, so I thought I had another 1000 hours to go. Should I change the bulb immediately, or do I have more time? The picture still looks fine.
Oh and it’s probably just the internal timer. Reset the lamp clock (while jotting down the total hrs) and your light will most likely go green again.
 

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Quick question. If I use HDR Tone mapping of MadVR should I still import JAVs curves or are they no linger necessary and would be doubling DTM effectively?

Should I still be imputing Dominic Chan's settings for example? Official JVC DLA-RS420 (DLA-X570R) Owners Thread

Many thanks
If you are tone mapping HDR into SDR you will not need the curves. I think you need to put the projector in the correct expanded color mode but it’s been a while since I have messed with it.


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If you are tone mapping HDR into SDR you will not need the curves. I think you need to put the projector in the correct expanded color mode but it’s been a while since I have messed with it.


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That's correct, if tone mapping from HDR to SDR you don't need the custom gamma curves as you just use the standard SDR gamma but set the color profile to BT.2020 instead of the normal one to take advantage of the expanded color space.
 

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In case anyone is interested - I found an old thread detailing how to add the missing second Iris to the low model JVC units. I was able to do this last night on my own RS420 and so far it had very positive results. The original post and my pictures detailing the process on my RS420 are in the above link. Obviously do at your own risk.
 

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^ Interesting, thanks for the link!
No problem! Honestly the second Iris made a pretty substantial difference I think so if anyone is interested in tinkering with their machine I think its potentially worthwhile - I wouldn't be surprised if it bridges a lot of the gap in performance between the RS420 and RS520 although the caveat is that I have not seen a RS520 in person. The original google doc posted by the thread starter is great, and I took a bunch of pics and added commentary to explain them all as well to further document the process. Took a few hours and only about $15 in materials to do..
 

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What was the improvement in CR and brightness reduction?
I unfortunately do not have a colorimeter so don't have absolute numbers for you. Subjectively there wasn't much decrease in output (atom, the thread starter from a couple years ago claimed about 20% reduction however I wouldn't have pegged it at that high), and the increase in contrast was substantial - easily seen in darker scenes - I rewatched the end of the recent Wandavision episode 6 and the scene with Vision flying over the town and the contrast was subjectively substantially improved. I historically had a CRT projector, and the baseline contrast on the RS420 was a little lacking in my estimation although I still thought the overall image was great. Note that the addition of the second Iris in the location documented in that thread is one of the main ways that the additional contrast has been obtained between the base model JVCs and the mid tiers for several projector generations, which remains true in the RS420.

"If we look at the RS420 by comparison, JVC claims the RS520 adds 100 lumens of light output, an increase in native contrast from 40,000:1 to 130,000:1, a difference of 400,000:1 vs 1,300,000:1 in dynamic contrast, full DCI-P3 color gamut coverage thanks to a yellow notch filter in the light path, THX certification with a THX calibration mode, ten lens memories positions versus five, a three year warranty versus two on the RS420 and a gloss black chassis with motorized lens cover. Additionally, through information gleaned from JVC’s engineers, we know that the RS520 offers full 12bit end to end video processing and displayed image. The RS420 has a limiting factor in the processing chain that forces the resultant image on screen to be 10bit only. It’s also known that the RS520 achieves its extra contrast performance through two means. Firstly, the RS520 has three current generation wire-grid polarizers, one for each color channel, whereas the RS420 uses only two current generation wire-grid polarizers and one last-generation wire-grid polarizer. The second mean to more contrast comes in the way of an additional iris in the light path. The RS420 lacks this additional iris but, like the RS520, has a single iris inside the lens to help boost contrast if the end user wants to utilize it. "
 

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JVC claims the RS520 adds 100 lumens of light output, an increase in native contrast from 40,000:1 to 130,000:1...

What they don't mention and has been pointed out by many is that the 3X CR increase comes at a high lumen cost.

So your results are interesting.
 

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What they don't mention and has been pointed out by many is that the 3X CR increase comes at a high lumen cost.

So your results are interesting.
Interesting to know - also implies that suppression of more light by a more restrictive second Iris might further improve contrast. I'm pretty happy with how it is currently and don't feel a tonne of need to test multiple Iris configurations at this stage, but would be an interesting experiment..
 

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What they don't mention and has been pointed out by many is that the 3X CR increase comes at a high lumen cost.

So your results are interesting.
I haven’t found that to be the case. My two RS500 are just as bright, if not brighter, than my RS400.
On the other hand, I have seen some used JVC projectors that have lost more than half the brightness, compared with new. It happens mostly when the projector operates in a dusty environment.
 

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I haven’t found that to be the case. My two RS500 are just as bright, if not brighter, than my RS400.

Are you saying with the 2nd iris closed on the 500's they're just as bright as the 400?

And with much higher CR?

Either way, an unknown variable here is lamp variability, unless you checked that by switching them.
 

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Are you saying with the 2nd iris closed on the 500's they're just as bright as the 400?

And with much higher CR?

Either way, an unknown variable here is lamp variability, unless you checked that by switching them.
I used the same lamp for the comparison.
“The same brightness” refers to iris open.
At -15, the RS500 is “dimmer” since it has a much wider range of adjustment. When adjusted for the same luminance, the RS500 consistently has higher contrast.
 

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OK good; very interesting.

Since there's a tradeoff between CR and brightness, I think of a pj's figure of merit as their product, so the 2nd iris improves it.

However, I'm not sure it invalidates the point which I didn't quite finish making:

If you value brightness over contrast, you won't want to use the 2nd iris.

When adjusted for the same luminance e, the RS500 consistently has higher contrast.
Does that include the 400 at max brightness?

If so, I rest your case :)
 

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OK good; very interesting.

Since there's a tradeoff between CR and brightness, I think of a pj's figure of merit as their product, so the 2nd iris improves it.

However, I'm not sure it invalidates the point which I didn't quite finish making:

If you value brightness over contrast, you won't want to use the 2nd iris.



Does that include the 400 at max brightness?

If so, I rest your case :)
Yes, the contrast advantage is noticeable even with the iris wide open.
I do not watch SDR at full brightness; always set it to 50-60 nits.
 

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Very interesting.

How wonder how that works.

Possibilities are

- Adding the 2nd iris catches stray light that doesn't add significantly to brightness but does add significantly to CR, since the amount of light contributing to the black floor is many orders of magnitude less

- JVC grades the panels and picks better ones for the upper models

- Something related to however they got 100 L more (which is itself a head-scratcher)
 
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