While on a business trip to the bay area last week I dropped by William Phelps office and talked shop. One thing that we talked about was the shading on the RS-1. There was a question on the forum awhile ago about whether or not the RS-1 uses different shading tables for normal and inverted operation. Wm confirmed that the RS-1 is similar to earlier JVC projectors and that it does have different shading LUT's for normal and inverted use. In fact you can see this for yourselves if you toggle the normal/inverted RS-1 menu. If you watch carefully, when the setting is changed the screen goes blue and you can briefly see parts of the screen change rapidly as the new LUT values are being applied.

The one thing that I didn't expect however is that the shading errors were reduced significantly when the normal/non-inverted configuration was used. Wm, mentioned that this is consistent with previous JVC projector lines because they were shaded from the factory in normal right side up orientation. To save time at the factory, The LUT for the inverted configuration is extrapolated from the autoshaded data rather than being measured directly which leads to shading errors when the projector is used in inverted mode.

The HD-1 that Wm had set up at his facility had nearly identical shading errors to the RS-1 that I have at home. They were so close in fact that it's obvious that the shading must have been done by computer rather than by hand. When we toggled the setting for inverted mode the areas on the screen with shading errors increased in both size and luminance.

The bottom line from all of this is that if you are concerned about reducing shading errors and if you have flexibility with your RS-1 installation, the normal right side up oreintation is the best (and with a minimal use of lens offset too).

(and with a minimal use of lens offset too).

Mark--I'm interested in any info you might have on how lens offset might affect image quality. For example, does max offset increase effects such as chromatic aberration?

Thanks,

Brian

Good find, Mark! With the large lens offset capability this projector offers much more flexibility for upright mounting.

Andy K.

Thanks. I was debating between ceiling (inverted) or shelf mount, sounds like shelf is the way to go

So would this be addressable if they provided LUT access? Is this correctable via a firmware upgrade?

So ceiling mounted means the projector must be inverted???

The bottom line from all of this is that if you are concerned about reducing shading errors and if you have flexibility with your RS-1 installation, the normal right side up oreintation is the best (and with a minimal use of lens offset too).
Thanks for the info, Mark! My RS-1 is shelf mounted with minimal lens offset used...:D

I don't know very much about these LUT tables, but is it possible for JVC to create a "corrected" INVERTED LUT table that they include in an upcoming firmware upgrade?

How much worse are these errors when inverted?

I don't have much option (longterm) but to ceiling mount my projector and I love the way the picture looks right now on the the coffee table, I'd hate to make it worse just by ceiling mounting it..... :(

Alternatively, anyone know of a good (commercial and buyable, not homemade) ceiling mount that allows the RS1 to remain upright?

anyone know of a good (commercial and buyable, not homemade) ceiling mount that allows the RS1 to remain upright?
Ditto!

Chief makes one, but of all the ones I've seen, they're kinda' butt ugly.

http://www.chiefmfg.com/client_files/www.chiefmfg.com/images/LCDA.jpg

Thanks for the info Mark. Glad I am doing a shelf mount. I actually was originally going to do a ceiling mount (purchased the RPA-U and had it at my house), but decided to do a shelf mount (to create a longer throw in my setup) to get more CR, and reduce lumens a bit.

Hmm...

Does this mean that if I ceiling mount it but use my vantage to invert the picture instead of the HD1, I am taking advantage of this as well?

Also does anyone know how to ensure that the horizontal/vertical lens shift is at its center indent? There does not seem to be a click or a marker to indicate that the controls are centralized?

Oliver

You don't need to invert the image if you don't invert the image[edit: make that "pj"], just shift it.

There's no lens shift detent that I notice, but not nohing would improve dramatically if there were.

It seems that is something that happens on a lot of projectors. Every pj I have used (all LCD) seems to have worse shading when inverted.

Too bad they wouldn't have the better optomized jig for inverted mode (as well as how it is on normal mode) because it is clear many ceiling mount. Oh well.

I don't suppose Wm had any news on the LUT access issue that you might be able to give us a hint about, did he?

So it seems my newly purchased Chief RPM-U mount will make my new RS-1 look bad. Projector is going up on Thursday, so could someone please recommend another alternative for me as I need to ceiling mount this unit and want it to look good (as well as the mount too!)

Dave

Dave,
I'm checking this too. Even though Chief make 2 mounts than hold PJ's normal and not inverted, they don't list them as fitting the RS1. I am gonna' check around more tomorrow to see what options there are.

When we toggled the setting for inverted mode the areas on the screen with shading errors increased in both size and luminance.

Mark,

I take it you did not physically invert the projector when trialling this 'find'. :cool:

There must be a reason for inverted values being different to upright values, so a non-conclusive test at best. ;)

As a Southern hemisphere resident, this may be advantageous....?

Cheers

Philippe

- Before every-one rushes out to get new mounts, and run the gauntlet of WAF :D

It looks like the LCDA-230C Chief mount will fit the RS1. Here's the link to the Chief page that has the specs.

Chief Mount (http://www.chiefmfg.com/client_files/www.chiefmfg.com/downloads/2005_Chief_LCDA_Series.pdf)

Would the Peerless PRS-45 mount work?

Just ordered the RS-1 for my father and trying to figure out what mount to get as well. New to the forums so I can't post a link to the pdf with specs and pictures. It seems the dimensions and weight work (recommends 25 lbs but I'm guessing the 25.6 lbs on the RS-1 is fine) It clamps onto the projector as opposed to screwing in or having it sit on a shelf so it may not look as obtrusive. Anyone see any potential problems?

Thanks,
Ankur

Why can't I think of any reason for a different shading "LUT" in table/ceiling mode? I mean it's the same panel right?

Ok, I will check if my Pearl has the same issue! Though it looks perfectly fine in ceiling position now! :D

regards,

Li On

Why can't I think of any reason for a different shading "LUT" in table/ceiling mode? I mean it's the same panel right?
It is either dependent on small gravity induced changes of panels, optics, lamp, etc. or (more probable) the LUTs are applied prior to orientation and lens shift.

In the latter case a firmware update should be able to fix this, although I don't expect it will happen.

Sounds like voodoo to me... :p

Ok, how about this? Inverted the projector but keep the orientation setting in table top and use external processor to invert the image?

regards,

Li On

Can you invert gravity too? ;) Because it is the physical tolerances and the flexing of the chassis that cause the various components to shift position ever so slightly from the normal to inverted position of the projector.

Vern

Can anyone confirm that the shading occurs irrespective of the physical orientation of the projector, and is strictly due to selecting "flip vertical" in the setup menu? That would be annoying. We have a wide couch centered along the (external) wall opposite an HP screen. I don't want to ceiling mount since this would lower the gain and throw light back onto the white ceiling, and the RS-1 is so big that a low shelf would be visually obtrusive and loom right over our heads. I am considering mounting the projector flat on the wall, firing vertically and using a 4" elliptical optical flat mirror to fold the beam horizontal. This requires that I flip vertical, and I'm hoping this doesn't needlessly degrade the image. Hard to imagine why it would produce shading other than a bug in the firmware if it is not a function of physical orientation.

Sounds like voodoo to me... :p

.....
Li On

I remember a similar issue with the G series as well as the HX2U.

In the G15, there was a little set screw to adjust the bulb when in the inverted position. It seems that when the projector is inverted, the bulb hangs differently(obviously,it's upside down) but the different geometry results in a different light output. When the projector is calibrated at the factory, it is in the right side up position so the filament/(arc gap?) is hanging down and the pj software is adjusted for the light it is putting out. The G10 and G11 had no such adjustment.

In the HX2U, a different (UHP, not xenon) bulb is used and there were some reports of bulb flicker in the inverted position. Again, my understanding from a comment Wm had posted several yrs ago was that the bulb was misbehaving due to the different orientation.

Theoretically, I cant explain why. it might be hard to understand how a pinpoint light source changes if it's orientation is changed. But the light source is not precisely a pinpoint, it is a very small line segment. Light from one end of the line segment strikes the dila panel at a different angle than light from the other end. Maybe, variations in the light output or spectrum along this line segment will be reflected differently by different parts of the dila panel resulting in shading variation?

If this is way off base, it's because I just watched Monty Python and the Holy Grail and the specious reasoning behind witch burning still has me chuckling.

Mark,

Can you in any way quantify the shading errors?

Is there a good scene from a DVD that one can use to test their RS-1 to see how bad it really is?

Sincerely,
snooktarpon

Hmm...

Does this mean that if I ceiling mount it but use my vantage to invert the picture instead of the HD1, I am taking advantage of this as well?

Also does anyone know how to ensure that the horizontal/vertical lens shift is at its center indent? There does not seem to be a click or a marker to indicate that the controls are centralized?

Oliver

What is the word on this? I'm pretty sure my lumagen will invert as well...

Wow, I've never seen so many concerned new owners (ok that's not true). Folks, if you haven't seen any increase in shading errors by mounting your RS1 upside down, then trust your eyes. This error which Mark describes and WM identified, as has been stated, is quite common, and is typically so subtle that it would take someone with WM's experience to point it out, to you. It's easy enough to test for yourself. Watch a movie with the projector upside down (and the picture right side up). Then watch the movie with the projector right side up ( and the picture right side up). I bet you can't tell the difference. If the RS1 is similar to its predecessors, even with test patterns it will take some look'n to see the differences between the two orientations.

So if you invert the image with a video processor, that won't be an issue right?

" So if you invert the image with a video processor, that won't be an issue right?"

No, it could still be an issue.

The whole potential problem is that the physical shading has the potential to change depending upon if the projector is inverted or not.

JVC adjusts the shading of the projectors right side up then I'd guess simply makes an upside down mirror image of of that for inverted mode.

The problem is that the physical shading of the projector can change when physically inverted... therefor the upside down mirror image shading tables are not accurate for what actually needs to be done when inverted. Likewise using the right side up tables are also not accurate for a physically inverted projector fed an inverted/mirror image signal from a video processor.

For long time DILA owners... how is the shading in comparison to say a G10?

Shawn

Shading seems much better on my RS1 than either of my G1000 or G15's did - but I dont know how much unit-to-unit variation there is (or was) so take that with a grain of salt.

Andy K.

"There must be a reason for inverted values being different to upright values"

The lamp is filled with high pressure gas; because of buoyancy the fireball will be in a different relative vertical position if the pj is inverted.

I'm not really clear on how it works, but my guess is that the slight change in angles of the light rays in the three optical paths is what causes the shading differences.

Mark or anyone

I want to mount my RS1 upright but at the top of the screen. Is that considered more lens shift than inverted at the top of the screen?
thanks

Anyway - I wondered about this, as my previous projector WAS affected by orientation - and I ended up having (much to my dismay) to shelf mount it. So before installing the RS-1 in it's final location (back of room/max throw/inverted) - I tested it for several days at the front of the room/min throw/table mounted - specifically noting any shading/CA errors. Maybe I got lucky for once - but I saw no appreciable difference in shading at either position/throw/orientation. CA was ever-so-slightly improved at max throw.

I'm about 85% happy w/ my shading - but there is definitely room for improvement. Hopefully (someday/somehow) wm can come to the rescue. If not - then I'll be looking to upgrade the RS-1 (RS-2/RS-3?) in the (near/far) future when the LUT adjustability becomes available (if ever).

I take it you did not physically invert the projector when trialling this 'find'.

There must be a reason for inverted values being different to upright values, so a non-conclusive test at best.


The HD-1 was physically inverted when we did this test.

You have a good point though in that YMMV. I'm not saying that every RS-1/HD-1 will benefit from right side up orientation, but rather that shading errors "may" be reduced on some units if the projector is mounted right side up. People shouldn't read this thread and jump to the conclusion that they need to automatically change their mounts though. The shading on their projector might be so good that there is no need to deviate from their preferred mounting setup. They might even have a unit where their shading is made worse by changing the orientation!

What this thread should do is alert those owners who have noticeable shading errors (like mine) that experimenting with the projector orientation might help to reduce some of these errors.

Can you in any way quantify the shading errors?

Is there a good scene from a DVD that one can use to test their RS-1 to see how bad it really is?


The shading errors on all of the production RS-1/HD-1s that I've seen so far (4 of them) are all very similar. The OOTB shading is actually pretty good and much better than the old G series projectors that a lot of forum members may remember. Unfortunately it's still not perfect though and it's visibly apparent with a uniform white field. There are several large horizontal bands that differ in both brightness and color from the rest of the field. The color shift is slight but the bands shift towards yellow/brownish. With most mixed scenes it's hard to see, but it's apparent with B&W movies and scenes with sky or clouds.


I want to mount my RS1 upright but at the top of the screen. Is that considered more lens shift than inverted at the top of the screen?


I have similar concerns. My projector is mounted in a soffit at the same height as the top of the screen. I have been using inverted mounting but I'm going to experiment with right side up orientation and see if this reduces the shading error on my unit. I prefer to use less than the max lens shift so I may hang the projector right side up, but below the soffit, but it really comes down to how much of an improvement (if any) I get in experimenting with this orientation.


Sounds like voodoo to me...

Ok, how about this? Inverted the projector but keep the orientation setting in table top and use external processor to invert the image?


Yes, William has commented in the past that the orientation affects the shading. It's not voodoo! :) I don't think that JVC would go to the extreme of having different LUTs for right side up and inverted position if it were voodoo lol. In fact when Wm calibrates units he specifically asks which orientation a person will use so that he calibrates it in that position to reduce these sorts of errors.

As far as using an external VP to invert the image goes, off-hand I'd think that this technique would have little benefit but if I were trying to minimize shading errors this isn't something that I would dismiss. Since these projectors can't currently be reshaded I wouldn't dismiss any approach that has an affect on shading... It's an interesting idea and one I'll try out :)


In the HX2U, a different (UHP, not xenon) bulb is used and there were some reports of bulb flicker in the inverted position. Again, my understanding from a comment Wm had posted several yrs ago was that the bulb was misbehaving due to the different orientation.


The lamp flickering problem was caused by running the lamp in one orientation for awhile and then switching the orientation. Wm noticed that this would sometimes cause the lamp to begin flickering prematurely. This does bring up a point though that experimenting with the orientation as I'm suggesting may cause the bulb to begin flickering prematurely. For me this is a price I'm willing to pay in an effort to reduce my shading errors, but others may not feel this way. As I said earlier in this post YMMV so take this thread and everything on the forum with a grain of salt :)

Anyway - I wondered about this, as my previous projector WAS affected by orientation - and I ended up having (much to my dismay) to shelf mount it. So before installing the RS-1 in it's final location (back of room/max throw/inverted) - I tested it for several days at the front of the room/min throw/table mounted - specifically noting any shading/CA errors. Maybe I got lucky for once - but I saw no appreciable difference in shading at either position/throw/orientation. CA was ever-so-slightly improved at max throw.

I'm about 85% happy w/ my shading - but there is definitely room for improvement. Hopefully (someday/somehow) wm can come to the rescue. If not - then I'll be looking to upgrade the RS-1 (RS-2/RS-3?) in the (near/far) future when the LUT adjustability becomes available (if ever).

Interesting story John and a good example of YMMV. Where did your RS-1 end up as far as alignment relative to the screen? (centered, top, bottom, etc.). I assume it was centered but just want to confirm that this was best for CA.

Yet another reason for lasers if this shading difference in inverted position has any dependence on the bulb.

My HD1 have some shadingproblems too, but it has actually gotten a lot better the last 10hours. I'm at 75 hours on the bulb as we speak.
I noticed no difference between inverted vs not inverted. The shading problems I have is basically a narrov purple field on the left edge of the picture (It stayed in the exact same position when I inverted the picture). I think it might be caused by the bulb, so maybe it goes away after some more hours :o

Btw. I also have the yellow bands, but it's barely noticable.

My HD1 have some shadingproblems too, but it has actually gotten a lot better the last 10hours. I'm at 75 hours on the bulb as we speak.
I noticed no difference between inverted vs not inverted. The shading problems I have is basically a narrov purple field on the left edge of the picture (It stayed in the exact same position when I inverted the picture). I think it might be caused by the bulb, so maybe it goes away after some more hours :o

Btw. I also have the yellow bands, but it's barely noticable.

Is your RS1 from the first or second batch?

If the inverted shading issue is really true you would think the reverse would be the case because I think more people use ceiling mounts than shelf mounts? Knowing this why wouldn't JVC set it up for ceiling mount being primary?

If the inverted shading issue is really true you would think the reverse would be the case because I think more people use ceiling mounts than shelf mounts? Knowing this why wouldn't JVC set it up for ceiling mount being primary?

This is a good question for JVC.

I read somewhere (WSR?) that the MF1 is factory calibrated (using Phelps software) for the inverted position and specifically for the ST 130.

Mark,
My alignment ended up at the top.

Mark,

Can you in any way quantify the shading errors?

Is there a good scene from a DVD that one can use to test their RS-1 to see how bad it really is?

Sincerely,
snooktarponShort of test DVDs that offer full field IREs, Greg Rogers has mentioned the beginning of Fargo with its almost solid white field snow scenes as torture tests for shading. Any movie that has similar ones will do. Look for colors other than white in such scenes that clearly aren't in the source. For example, my RS1 is not inverted and starting on the right edge going inward I see magenta for about 5% of the image, then a much more subtle greenish tone for another 5%.

Someone posted that a prominent LCoS calibrator, not specifically named as wm but clearly it was he, reported that he didn't think there'd ever be end-user shading adjustments for the RS1/HD1, which if true is really unfortunate.

So, pending any effective software fix, any idea anyone comes up with to deal with shading difficulties will be welcome.

Dan

Is your RS1 from the first or second batch?

I have an HD1, not RS1 (if that matters).

I have no clue whicht batch it is from, but I got one of the first that arrived in Norway.
I got it in the end of march.