I'm sure this is simply ignorance on my part and I apologize in advance, but thinking of the RS2, what does a higher contrast ratio really bring to the table?

In my itty bitty brain, I'm thinking that brighter colors are simply, well, brighter, creating a farther spread between black and white. But my undertanding of LCOS and ANSI contrast (which may be flawed) makes me wonder if ANSI contrast would actually decrease due to more light spill from the brighter colors.

In my opinion, the RS1 seems to suffer more from lack of depth in bright scenes (and I'm assuming this is due to its low ANSI contrast). Can someone tell me how an improved contrast ratio would affect this?

I just want to correct any flawed, internal logic I have going on here... :-)

Thx.

In my opinion, the RS1 seems to suffer more from lack of depth in bright scenes (and I'm assuming this is due to its low ANSI contrast). Can someone tell me how an improved contrast ratio would affect this?

Thx.

It's interesting that DLP suffers the opposite. When I recently compared a DLP side by side there was more dimensionality to high APL (bright) scenes compared to DILA but the opposite in lower APL scenes. By lower APL I don't just mean very darkest of dark scenes either. IIRC JVC mentioned they had improved the light engine to reduce scatter and I imagine whilst it may not be at DLP levels the ANSI may have improved. Feeback from a recent dealer event reported the HD100 had increased dimensionality compared (side by side) to the HD1. Not sure if this is due an increase in ANSI or other aspect.

D

Ian,

"In my itty bitty brain, I'm thinking that brighter colors are simply, well, brighter, creating a farther spread between black and white. But my undertanding of LCOS and ANSI contrast (which may be flawed) makes me wonder if ANSI contrast would actually decrease due to more light spill from the brighter colors."

Think of it this way... to double the contrast you either need to be twice as bright with the same black level or have the same brightness and cut the black level in half. (Or of course a combination of the two... simplified here)

From what I have seen if the RS-2 it sounds like it puts out pretty close to the same brightness as the RS-1. So to double the contrast it went the direction of making black level half the level it is on the RS-1.

Shawn

In my itty bitty brain, I'm thinking that brighter colors are simply, well, brighter, creating a farther spread between black and white. But my undertanding of LCOS and ANSI contrast (which may be flawed) makes me wonder if ANSI contrast would actually decrease due to more light spill from the brighter colors.

.

dazzerxxx beat me to it, but the JVC description of how they achieved higher contrast is actually by reducing stray light, rather than increasing it as you fear. From the JVC literature on the new RS2:

The projectors’ new 0.7-inch 1920 x 1080 D-ILA devices reduce stray light caused by the dispersion and diffraction of reflected light. JVC decreased orientation irregularities by reducing the gaps between pixels, adopting improved liquid crystals and other innovative technologies, enabling the device itself to achieve a contrast ratio of 40,000 to 1.

The enhanced optical engine dramatically improves the precision of light polarization, helping to prevent light leakage into the projection lens and allowing for true black level reproduction. For optimum image quality, the new projectors incorporate video processors from Gennum Corporation that offer high-precision scaling and Gennum’s VXP™ technologies.

Unless the ANSI went up as well, you're probably correct that the improved on/off won't help out bright scenes.

If JVC achieved deeper black levels through controlling light bleed/stray light, I don't understand why it wouldn't increase ANSI contrast to some degree. I mean, aren't those precisely the types of factors affecting ANSI?

Ian,

"In my itty bitty brain, I'm thinking that brighter colors are simply, well, brighter, creating a farther spread between black and white. But my undertanding of LCOS and ANSI contrast (which may be flawed) makes me wonder if ANSI contrast would actually decrease due to more light spill from the brighter colors."

Think of it this way... to double the contrast you either need to be twice as bright with the same black level or have the same brightness and cut the black level in half. (Or of course a combination of the two... simplified here)

From what I have seen if the RS-2 it sounds like it puts out pretty close to the same brightness as the RS-1. So to double the contrast it went the direction of making black level half the level it is on the RS-1.

Shawn
You get better number by cutting the low level light output. A dynamic Iris is a good example of this. This is the beauty of dividing by a fraction.

Ian,

Think of it this way... to double the contrast you either need to be twice as bright with the same black level or have the same brightness and cut the black level in half. (Or of course a combination of the two... simplified here)

From what I have seen if the RS-2 it sounds like it puts out pretty close to the same brightness as the RS-1. So to double the contrast it went the direction of making black level half the level it is on the RS-1.

Shawn


Ahhh. My itty bitty brain is a teeny weeny bit bigger now, thanks all.

I'm sure this is simply ignorance on my part and I apologize in advance, but thinking of the RS2, what does a higher contrast ratio really bring to the table?

In my itty bitty brain, I'm thinking that brighter colors are simply, well, brighter, creating a farther spread between black and white. But my undertanding of LCOS and ANSI contrast (which may be flawed) makes me wonder if ANSI contrast would actually decrease due to more light spill from the brighter colors.

In my opinion, the RS1 seems to suffer more from lack of depth in bright scenes (and I'm assuming this is due to its low ANSI contrast). Can someone tell me how an improved contrast ratio would affect this?

I just want to correct any flawed, internal logic I have going on here... :-)

Thx.

You are correct, that if the static on/off CR improves with no change to ANSI, there will be a decrease in shadow detail visibility because less of the luminance range will be captured by the ANSI CR range in any bright simultaneous scene. However, you do gain significant improvements at low APL where the improved on/off provides significant benefits. Bottom line, you want increases in BOTH on/off and ANSI.

"You are correct, that if the static on/off CR improves with no change to ANSI, there will be a decrease in shadow detail visibility because less of the luminance range will be captured by the ANSI CR range in any bright simultaneous scene."

I don't see how you reached that conclusion.

Increasing on/ff CR with everything else the same lowers the black floor, which if anything would expose more shadow detail.

Seems to me that the worst that could happen is that the additional detail is not visible because of washout by brighter parts of the image.

"You are correct, that if the static on/off CR improves with no change to ANSI, there will be a decrease in shadow detail visibility because less of the luminance range will be captured by the ANSI CR range in any bright simultaneous scene."

I don't see how you reached that conclusion.

Increasing on/ff CR with everything else the same lowers the black floor, which if anything would expose more shadow detail.

Seems to me that the worst that could happen is that the additional detail is not visible because of washout by brighter parts of the image.

This is my understanding too. If the ANSI cr is kept the same while the on/off cr is improved, the shadow detail in dark scenes will be improved to the degree that the on/off contrast was improved. With brighter scenes there will likely be a small but measurable improvement. In both cases though (bright scenes and dark scenes) there shouldn't be a loss in shadow detail (only an improvement).

To answer the OP's question. More contrast is always a good thing. The RS-2 should have about half the black level of the RS-1 and this should be very perceptible on fade to black scenes and also really dark scenes. I'm sure in my HT that it will make a significant difference. More contrast is always nice but I'm of the camp that would like to see JVC fix some of the other things about the RS-1 first before improving contrast.

"I've noticed the opposite, that a higher speced and measured on/off contrast projector can have poorer shadow quality than a much lower one. If colors are messed up, and the gamma curve is not completely smooth..."

Those problems are not a result of better contrast, other than the mfgr thinking the good CR lets them get away with it.

So what would the contrast ratio be if they fixed the color accuracy?

IB

Will their new machine that is supposed to have a 30,000 to 1 contrast ratio have more accurate colors?

Is it a new LCOS chip they are using, or light path changes to achieve the 30,000 to 1 spec?

IB

This is my understanding too. If the ANSI cr is kept the same while the on/off cr is improved, the shadow detail in dark scenes will be improved to the degree that the on/off contrast was improved.

Yes, on very dark scenes, as I hope I made clear.

With brighter scenes there will likely be a small but measurable improvement. In both cases though (bright scenes and dark scenes) there shouldn't be a loss in shadow detail (only an improvement).

With brighter scenes, the improvement in on/off CR will either not have any significant impact, or will decrease shadow detail visibility. In bright scenes, you're really only seeing a slice of that massive on/off CR range, roughly what the ANSI CR is. Below that range, much will be lost because of spill. If you increase the on/off CR range and hold ANSI constant, you're looking at a smaller relative slice of the on/off CR range. On the other hand, the luminance deltas are slightly increased, but I think that improvement will be overwhelmed by spill, thus leading to an overall negative for bright scenes in terms of detail visibility.

You can test this easily on a CRT display, by raising and lowering black level (and making sure that white level remains constant, which means slightly altering white level in the opposite direction you are moving black). What you are doing is basically changing the effective on/off CR of the CRT display, while ANSI remains physically constant. If you make absolute black very low, shadow detail suffers in mixed scenes because a greater portion of that detail falls outside what I guess you could call your 'ANSI window' (which is small on a CRT because ANSI CR is low). If you raise black level, you recover shadow detail visibility in those brighter scenes because more of that detail is pushed up into the ANSI window. In other words, if your on/off CR is low enough that it is basically approaching the same as your ANSI CR, you should be able to see all the shadow detail, all the time. But of course, this will look terrible on low APL scenes as we all know.

To answer the OP's question. More contrast is always a good thing. The RS-2 should have about half the black level of the RS-1 and this should be very perceptible on fade to black scenes and also really dark scenes. I'm sure in my HT that it will make a significant difference. More contrast is always nice but I'm of the camp that would like to see JVC fix some of the other things about the RS-1 first before improving contrast.

I definitely agree with that. I don't mean to insinuate that increasing on/off CR is a bad thing, which someone could take away from what I said briefly above. Increasing on/off CR is definitely a good thing. But it may also expose other weaknesses, such as ANSI CR. In any case, the negative specifically for bright scenes where ANSI dominates, can easily be reverse by artificially elevating your black level, and lowering the on/off CR performance of the display. Why anyone would want to do that is beyond me, but it simply illustrates that more on/off CR is ALWAYS a good thing, since a user can easily reduce the effective on/off CR they're getting from their display, but a user can't go the other way.