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Discussion Starter · #1 ·
Greetings. My brother bought this projector, and we're starting to get things situated. At the end of the process, our setup will be the G150CL with ISCO-II, Denon AVR-5803, HTPC->DVI->projector, everything else->Leeza->RGB->projector, and even some velour curtains (color undecided) and full-aniline leather furniture (we currently own some wicker-and-metal jobs that are falling to pieces).


We haven't yet switched the projector on. Eventually I will be able to tell everyone, once and for all, the truth about its DVI input (whether or not it can handle a resolution matching its panel, pixel-perfect). This will probably be the first time the truth becomes common knowledge, as both the manual for the projector and patently clueless JVC representatives have proven inconclusive.


The first thing I wanted to ask about was the lens placement. My brother installed it, but I could not help but notice that the lens doesn't fit in the dead center of the gaping hole at the front of the projector. Instead, it is situated towards the top of the hole, leaving perhaps a third of a centimeter of space at the top, and perhaps three centimeters below. Horizontally, it seems more or less okay. The simple drawings of the projector in the manual do not indicate that the lens should be anywhere other than the dead-center of the hole.


I'm a bit concerned by this. Is it normal? How will this affect the future installation of an ISCO-II lens?


Second question: Ceiling mounts. We intend to install this on the ceiling. Well, for one thing, it's possible that we'll have to install it on a sloping portion of the ceiling. But the main concern is that there do not appear to be ANY ceiling mounts custom-designed to mount this projector. My brother bought a rather expensive model designed for the G15 (or so I am told) and it turned out not to be compatible.


Does anyone know who might sell a ceiling mount for this projector?


On a related note, the manual talks about the necessity of adjusting a special screw if one wishes to use the projector upside down. It explains that this is intended to correct variances in shading. This seems a little worrisome. If the projector is so sensitive to orientation that one needs to adjust a screw just to enable ceiling usage, then this suggests that even after it's been adjusted, the resulting image will never be 100% perfect, meaning that the shading variances will be there, to some degree, no matter what, and probably would be even with right-side-up usage. I've never heard of this problem before.


The manual also says that if one wishes to ceiling mount, they should consult an expert. The exact quote: "To ceiling-mount and adjust the projector, special expertise and technique are necessary. Be sure to ask your dealer or a specialist to perform this work." Is this saying that one needs to actually re-calibrate the projector for ceiling use? Or is it just a disclaimer against unskilled consumers? I'm guessing the latter, but it would be disappointing to discover that this pre-calibrated projector will need a calibration anyway, just because we have to stick it on the ceiling.


And while I'm on the topic, where does one look to find low prices on Cermax lamps? I've searched for and found lots of discussion about the lamps and their cheapness and installation, but nothing straightforward like, "Oh, and here's a link to somebody who's actually selling them."


Thanks in advance. I already have high expectations for this projector, so I'm not likely to come back with excited summaries of how awesome the image is. Since we are jumping directly from a 27" TV to the best possible projector image, we haven't had the standard period of adjustment to screen-door LCD images, so I'm not expecting to be wowed or anything.


But maybe I'll at least drop by and confirm that there are no rainbow artifacts in sight. ;P
 

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Colmino,


Welcome to the G150 club! Here's my experience with the questions you raised:


Lens placement - The skimpy manual that comes with the lens is not as clear as it could be. My pointers on the lens are A) make sure you remove both the front and rear lens caps. I initially only took the front lens cap off and left the rear lens cap on and had to disassemble everything when I discovered this error. B) Routing the lens motor wires to the clamp depicted in the manual illustration was a little tricky as there is not much wire to work with and the last thing you want to do is somehow disconnect these wires from the lens motor, but getting this routing right is important as it will keep the lens motor wires from getting tangled in the lens gears later when you are zooming or focusing the lens. C) I used a worklight shining into the projector to see this, but it is also important to make sure that the top lens locator pins are perfectly aligned with the locator holes on the lens. The locator pins are black and the area surrounding the locator holes are all black as well, so it was difficult to tell whether these were aligned perfectly without the worklight. The top of the locator pins should be flush to the area surrounding the locator holes on the lens when they are perfectly aligned. Initially when I had the rear lens cap still on the lens, the locator pins were not totally flush, but after removing the lens cap they were totally flush. D) When the lens is installed properly, you are correct that it will not be center to the hole in the front panel and instead will be closer to the top of this hole. The simple drawing is not to scale and does not illustrate this properly. You will notice however that the black sleeve that covers the lens and the rest of front panel lens opening is similarly constructed such that the hole for the lens is more to the top of the lens opening. Try to get as tight a fit between this black sleeve and the lens as possible since any gap in this fit will show up as a halo surrounding your projected image. Initially I did not pay much attention to this fit and had a significant halo around the image particularly when using a short throw distance for testing purposes. After adjusting the sleeve to lens fit for a tighter fit, it all but eliminated the halo. In my case I still do not have a perfectly tight fit and will have a faint halo on shorter throw distance projections, however a) when projecting from my normal throw distance of 16 ft. on a large screen with complete black boundaries there is no halo at all and b) it looks like it would be easy enough to supplement the fit of the black sleeve around the lens with other material if it was needed.


Ceiling mount - It looks like there are only a few mounts out there specifically for this projector since it is still fairly new. I've had several sources recommend the Chief Manufacturing mount. They cover the G150, however last I looked their cross reference at their website was incorrect and would have put you in a mount for the G15. The G150 is the exact same dimensions and case as the JVC M2000 which gives you the correct cross reference for the G150. For the inverted ceiling mount which I will be using, the correct model number for the Chief product is RPA-3020. I even called Chief and indicated the issue with their webpage and had them doublecheck that the RPA-3020 would indeed match the G150 and they agreed with my assessment. Obviously check with Alan and the AVS guys as I understand that they can order it for you, but you can also find it at several websites for well under $200.


Ceiling mount expertise - My guess is that it is a disclaimer. I think there is a similar disclaimer around installing the lens somewhere. Obviously you can perform these operations on your own with the proper level of care, but it is always useful to have a second set of skilled hands on any ceiling installation.


Re-calibration after ceiling mount - Have not played with the position selecting screw for ceiling mounting yet so don't know much about this yet. Will it need recalibrating - possibly. Frankly I do not plan on doing any calibration until I have it mounted in its final position. Will the factory calibration be sufficient? Possibly, but I'm not necessarily relying on that and suspect that it will require a little fine tuning ceiling mounted or not. I think the factory calibration is a great starting point as it produces a great picture right out of the box, but at a minimum I plan on validating the calibration for myself when it is in its final position. For instance, the factory set blacks are good, but could use a little punching up from my eyes.


Cermax lamps - have not gone lamp hunting yet, so don't have much to add here. There have been some good threads on Cermax lamps in the past on the forum, so a good search on Cermax will probably turn up some pointers.


Looking forward to your DVI assessment.


Have Fun,


Mark
 

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Quote:
Originally posted by Colmino


The first thing I wanted to ask about was the lens placement. My brother installed it, but I could not help but notice that the lens doesn't fit in the dead center of the gaping hole at the front of the projector. Instead, it is situated towards the top of the hole, leaving perhaps a third of a centimeter of space at the top, and perhaps three centimeters below. Horizontally, it seems more or less okay. The simple drawings of the projector in the manual do not indicate that the lens should be anywhere other than the dead-center of the hole.


I'm a bit concerned by this. Is it normal? How will this affect the future installation of an ISCO-II lens?
Yes - that's completely normal. If the G150CL were a "center-aligned" projector - one where you aimed the center

of the lens at the center of the screen - then you would have to center the ISCO-II lens with the center of the

projector's lens.


But the G150CL is not a "center-aligned" projector - it is an "edge-aligned" projector. It's beam doesn't expand both up

and down from the lens - only up [ up to an upright projector] So you should not imagine a beam coming straight

out of the projector lens - the beam is angled upward.


Because of this - the center of the ISCO II has to be at the center of the beam - but because the ISCO is a short distance

in front of the G150CL - the center of the beam at the ISCO's location is higher than the center of the lens - all

because the beam slants upward.

Quote:


On a related note, the manual talks about the necessity of adjusting a special screw if one wishes to use the projector upside down. It explains that this is intended to correct variances in shading. This seems a little worrisome. If the projector is so sensitive to orientation that one needs to adjust a screw just to enable ceiling usage, then this suggests that even after it's been adjusted, the resulting image will never be 100% perfect, meaning that the shading variances will be there, to some degree, no matter what, and probably would be even with right-side-up usage. I've never heard of this problem before.
The projector will work fine without adjusting the screw - in fact the G11 doesn't have that screw. However, there is

a small effect due to the fact that gravity is pulling "up" as far as an inverted projector is concerned. That screw

will compensate for the gravity effect. Think of it as a

fine tuning control.


Dr. Gregory Greenman

Physicist
 

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The G15 also has an adjustment screw to compensate for an inverted mount. When ceiling mounted the arc in the Xenon bulb "sags" a bit which throws it out of alignment with the optics and can lead to shading problems. The adjustment screw moves a condenser lens which brings the arc back into alignment with the optics.


IIRC, the G15 has two shading memories (one for normal and one for inverted mounting), and the G150CL incorporates "zone shading" which makes it much easier for a calibrator to eliminate shading problems.


Mark Hunter is working on a shading tool for Dilard to make the shading user-adjustable, which will be useful for touching up the shading after a bulb change. Last week I replaced the bulb in my G10 and noticed the unformity isn't quite as good as it used to be (but still not objectionable).


Contact Ralph at Altas Lighting for replacment Cermax bulbs.

Forum member Dave Leddon has a good webpage on how to replace the lamp including contact information for Atlas. http://home.attbi.com/~DILA/


Cheers,

Dave.
 

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Discussion Starter · #5 ·
Thanks for the great replies. All my questions were fully covered, which leaves me no choice but to ask some new ones. :)


About the only thing I'm curious about now is DVD players. Key Digital offers a free SDI-modded DVD player with their Leeza. Due to the nature of my Leeza purchase, I did not get this DVD player, but Key Digital is of course willing to sell me one.


The Key Digital rep with whom I was speaking had to recently leave for some convention, and neglected to mention the player model, although I gathered it was a Panasonic. I suspect it is the RP56. Anyone know for certain?


But the biggie is this. Can the RP56 (or _any_ SDI-modifiable DVD player) output 24 or 48 or 72Hz? Since the RP56 already boasts a progressive output, I'm logically inclined to suspect that it can in fact output video at a film-compliant refresh rate, but it would be nice to know the truth.


It would be a shame if the only digital-and-24Hz solution is a kludgy, noisy HTPC with a non-user-friendly interface.


Since I do have a Leeza at my disposal, perhaps there's a way I can get the desired results by using it? I've been taking it for granted, after all, that the only way to get 24/48/72Hz progressive DVD video is directly from the source (a HTPC, or hopefully a DVD player), and all other methods would be nothing but 3:2 pulldowns or similar compromises, introducing judder.
 

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Quote:
Originally posted by David Panko
The G15 also has an adjustment screw to compensate for an inverted mount. When ceiling mounted the arc in the Xenon bulb "sags" a bit which throws it out of alignment with the optics and can lead to shading problems. The adjustment screw moves a condenser lens which brings the arc back into alignment with the optics.


IIRC, the G15 has two shading memories (one for normal and one for inverted mounting), and the G150CL incorporates "zone shading" which makes it much easier for a calibrator to eliminate shading problems.
1) I have found that the adjustment screw only affects light output, it does not seem to do anything to the shading. When you invert a D-ILA projector, the light output decreases. The screw helps to compensate for this.


2) The G15 does NOT have two shading memories, it only has one. Worse yet, when the projector is inverted, the shading is inverted too, but since it's more panel related, it probably should not be. That's why a projector needs to be calibrated for inverted use if it's going to be used that way. There is even a small disclaimer to this in the JVC owner's manual.


William
 

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the Leeza can output 72hz, regardless of what the sd inputs are as long as they are interlaced. any progressive or HD via the HD inputs will be passed through with no change at all.
 

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Quote:
Originally posted by Morbius


The projector will work fine without adjusting the screw - in fact the G11 doesn't have that screw.
Well, yes, it will work, but you'll give up a significant amount of light output if you don't adjust it. All you have to do is back it out a few turns.


William
 

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William,


Have you seen a DVI inputed G 150?


I do wonder how this will compare to one of your G-15s.


Jeff
 

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Discussion Starter · #10 ·
> the Leeza can output 72hz, regardless of what the sd inputs are as long as they are interlaced. any progressive or HD via the HD inputs will be passed through with no change at all.


Hmm. So in other words, if I want the SDI DVD player -> leeza -> projector to result in 24Hz video, this can be accomplished, but only if I make sure the DVD player sends non-progressive video?


Wouldn't this result, somewhere, in loss of quality?


Too tired to actually think it through. :p
 

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as far as i know all sdi dvd signals are interlaced.
 

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While the G150 handles both interlaced and progressive signals on some of the inputs, using a RP-56 DVD on the component inputs, it seems to give a slightly better picture to my eyes with the RP-56 interlaced signal as opposed to the progressive signal. I've seen this in other situations as well where sometimes you are better off sending the interlaced signal into the projector and letting it's internal scaler do the work.


Mark
 

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Colmino, the SDI of your DVD player uses the interlaced signal only. There's no way to send a progressive scan signal over SDI. [Edited: corrected from "DVI"] The Leeza therefore does the deinterlacing. That's exactly the way it should be---the whole point of an SDI input is to feed the original interlaced video signal directly to the deinterlacer without the loss in quality that results from a D/A-A/D conversion pair.


I don't know if the Leeza accepts 480p inputs, but if so it might be interesting to hook both the SDI output and progressive component outputs to the Leeza, so you can A/B them. It may be that the Faroudja deinterlacing will be better for video-based DVDs.
 

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Discussion Starter · #15 ·
> Colmino, the SDI of your DVD player uses the interlaced signal only. There's no way to send a progressive scan signal over DVI. The Leeza therefore does the deinterlacing. That's exactly the way it should be---the whole point of an SDI input is to feed the original interlaced video signal directly to the deinterlacer without the loss in quality that results from a D/A-A/D conversion pair.


Alright, thanks. Would then it be safe to assume that the Leeza could recognize DVD film video (or however you want to call it; 24Hz) and ultimately convert it into 24 or 48 or 72Hz progressive? What I'm trying to do is an all-digital transfer from DVD to projector, without the introduction of judder. This means (for films) 24Hz. I know the Leeza should probably be able to do this, but then it also makes sense that a LCOS projector could accept video at its panel's resolution, but the Hitachi 5500 proves that assumption false, so it's not a good idea to assume too much.
 

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Well, that depends on both the Leeza supporting 24/48/72Hz and the G150 accepting the same. I don't have either one (yet) so I couldn't answer that... but at least you can test the G150 using an HTPC...
 

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Correct me if I'm wrong, but I thought that the G150 would only display 60Hz signals. It may (or may not) allow 48 or 72 Hz signals as input, but by the time they get to the display, my understanding is that it will be displayed at 60Hz no matter what rate you feed it, just because the panel driver hardware is locked at 60Hz. I'm basing that on having heard that the older DILAs were limited to 60Hz; I haven't heard anything specific about the G150, so if they introduced variable rate output as a new feature it is possible. Certainly I would check out the projector specs before going to any trouble to get the non-60Hz input.


-Tom
 

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a few notes:


"There's no way to send a progressive scan signal over DVI." not true at all. you mean "SDI"


Option 1: the leeza will out put everything as rgbHV, analog;

Option 2: the leeza will out put all analog as DVI and HD or progressive inputs as unchanged analog over the rgbhv output.


both options are available simultaneously;

the Leeza has 4 standard def inputs that must be interlaced, one of which can be sdi (interlaced); it has 3 HD inputs which can be HD interlaced, HD progressive or sd progressive.


transcoding only is available for the three HD inputs (if you input component progressive or HD, the Leeza will output RGBHV progressive or HD, otherwise, unchanged.

all 4 SD inputs will be output at the rate (50hz, 60hz or 72hz) that you select and the res that you select (there is a large list) and the signal will be progressive. with 60 hz, the Leeza will perform 3:2 pulldown , converting 24 frame material (film) to video, and 3:3 pull down at 72hz. all 4 sd inputs can individually have variables set for contrast, brightness, color sat, color r, and color b.


Aspect ratio can be also be set for the output as well as anamorphic un-squeeze.


one last detail: all inputs are bnc (there might be a 15 pin d for one of the HD inputs?) or s-video, you will need an s-video to 2-bnc breakout cable; you might also need female rca to bnc adapters, if your present cables have rca ends. the sdi connector is bnc.

the various inputs all have about 7 bnc connectors each! two are for 2-ch audio, should you want to select that using the Leeza as an audio wswitcher as well; the others can be menu configured as composite (using 1 bnc), s-video (using 2 bnc's), component (using 3 bnc's), RGBHV (using 5 bnc's).

only input 1 can also accept sdi, via 1 bnc.


you could A/B the dvd player by sending interlaced to one of the sd inputs on the Leeza and progressive to one of the HD inputs
 

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Tom, all D-ILA's are able to display variable refresh rates. The hardware isn't locked to 60Hz, but instead the panel is updated at twice the incoming refresh rate (with a range of 48Hz to 85Hz).


Cheers,

Dave.
 

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You're correct, I did indeed mean to say: "There's no way to feed a progressive scan signal over SDI." I believe Colmino got the point though. Post has been corrected.
 
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