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I am about to install a g15 in a high end home theater...and I am trying to decide whether to have is professionally calibrated or buy Dilard. The slight cost difference isn't a big deal...and I really don't need any of the other automation features of Dilard, as this projector will be controlled via rs-232.


Will Dilard calibrate as well as, or almost as well as a professional such as Cliff?


Thanks for your opinions, and I am looking forward to seeing a bunch of you at CEDIA!
 

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Don't know about the G15, but my projector needs to be tweaked depending on the source. I would rather have the ability to do it myself.
 

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"Will Dilard calibrate as well as, or almost as well as a professional such as Cliff?"


acaciolo,


That will be answered very soon, but more importantly, the question should be is the Dilard/Colorimeter the right purchase, or is a calibration by Cliff/William the right purchase?


It's a well known fact that the calibrations by Cliff and William have been very successful and those who have had them are indeed very satisfied.


It's also well known that the Dilard software has been an invaluable option to many in getting the most out their DILAs. Automation, scaling, geometry, macros, Pronto-Airboard files, pixel alignment, etc.


Since calibration of the DILA is, IMO, a necessity for the serious DILA owner who wants to get the most out of it, the question becomes whether or not you need the plethora of features Dilard 2.2 will have to offer, or whether or not you feel a one time calibration done by others will be all you'll ever need.


I asked myself that very question when Dilard first hit the scene and decided that even though the full calibration wizards were some time off, I'd bide my time and wait.


Boy how time flies. http://www.avsforum.com/ubb/biggrin.gif The moment is near. My G11 is starting to salivate.


The thought of sending my DILA to William for calibration crossed my mind many times. I know I would have been satisfied with the results. I was very tempted and even got all the details of how to go about it, but............?


I just had to see for myself how the story ends. http://www.avsforum.com/ubb/smile.gif I have full confidence in the statements Mark and Kevin have made in what the calibration wizard will give.


Of course, with this ending comes a new beginning in the birth of Colorfacts. What great times we live in, huh?


As to speaking strictly of which calibration will be better? I believe we'll see that both methods take the DILA to new heights and the decision of which one depends on many different variables.


Chris
 

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Has anyone noticed if the calibration of a DILA drifts over time? (Or perhaps that's a function of the bulb aging). Does a new bulb require re-calibration or is it essentially the same as the previous bulb? If the answer is yes to any of these questions, then Dilard + ColorFacts makes a lot of sense to those wanting the ultimate reference screen.


Most of us should be less picky and spend more time watching videos with our friends and families. http://www.avsforum.com/ubb/smile.gif


BTW: I've yet to actually install my Panamorph and it's been sitting around for about a week now. After a year, what's another couple of weeks....

-=-

Mark Hoy
 

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Does 2.2 include the "Shading Wizard"? I assume that a manual calibration includes this step. I know that my Dila (an old G1000) required a fair amount of tedious adjustment to get the shading uniform across the screen.


Also, how does the Calibration Wizard establish 0 IRE at the correct voltage at the inputs? Without an external reference input, isn't this pretty much impossible to do?


I've got to believe that there is enough variation amongst the video cards that you can't just output some arbitrary value and hope that the computer is really sending .07 volts (for example) to the projector...
 

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mjws,


Having tried 5 video cards before arriving with a "golden" unit I can emphatically state that there is a great difference in the quality of the signal produced based on the proper output voltage of the video card. To have your card properly set-up requires an oscilloscope to monitor the voltages at 7.5 and 100 ire and adjust the cards software to arrive at the best performance settings . There are other issues aside from improper voltage which may create problems for the calibration to be accurately performed. Price is not necessarily the determining factor in the quality of the video card as ultimately my most expensive card does not have the most linear output or the best picture quality!


Certain cards exhibited artifacts in the lower ire range making it very difficult to properly complete eight bar adjustments. Try performing a blue offset adjustment for eight bar at 30 ire with noise present in the signal! It is enough to make you go blind.


Although the gamma look-up table is globally used by all inputs, Component, and Y/C, inputs require separate White Balance adjustment. This calibration requires a signal from either a generator with these types of signal outputs or an appropriate source (Progressive DVD Player) with a flat White field to measure and calibrate to.


Shading for the current projectors (G11, G15, G20) requires the calibrator (person) to make a number of compromises to arrive at the best picture quality (flat-field uniformity). Ideal flat-field uniformity is generally not something that can be produced in the lower ire levels of a DILA projector.


[This message has been edited by ghibliss (edited 09-04-2001).]
 

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I suppose you are going to need a less biased response, so I personally won't make any comments on the appearance of the end results, preferring to leave that to others.


I do think that Dilard takes much of the "guesswork" out of the operation. Since a digital video calibration is almost completely mathematical, it is a task ideally suited for a computer.


I don't believe that you will find anyone calibrating D-ILA projectors by hand anymore, as everyone uses a computer to do at least some of the mathematics. Dilard just takes that to the logical conclusion.
 

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I took a g15 to Cliff and witnessed his procedure. While I have no doubt that Dilard calibration will do a lot to improve things, he did many things I would think twice about before attempting myself. The major item that cannot be automated was opening the unit up and adjusting the set screws on the polarizing filters.

He manually adjusted these to achieve the most light blockage (like polarized sunglasses). I would guess that the best black level cannot be reached without this process.

My understanding is that calibration is a one time thing with dila's since the lamps are and stay very uniform (not necessarily true for other projectors).

It was fascinating to see readouts on his scope for successive passes of the software and to see the changes on the image projected. I was most surprised by how many adjustments were performed by eye (always confirmed by scope to make sure things were really improving). I wonder if folks like Cliff and Mark, who make and market analysis tools have keener eyes to know what to look for when adjusting?

Randy
 

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Randy,


It is true that Dilard will never be able to do any physical operations to the projector. If you need the projector case opened, you will need to take the unit in for this service.

Quote:
I was most surprised by how many adjustments were performed by eye (always confirmed by scope to make sure things were really improving).
The Dilard Wizards just take the eye out of the equation, and does everything by the 'scope to begin with. It saves a step, and decreases the variability in the performance.


By the way, I don't have magical eyes at all. In fact, I use the colorimeter to "see" things that I can't see at all!


In the future, I think that many devices will have the ability to "auto-calibrate" themselves using a device that can monitor their performance (colorimeter), and another device that can make decisions on reaching a pre-defined target and actually making those modifications (computer-like device).


I also have no doubt that the sensitivity of such systems will be far greater than the human eye can see.
 

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I believe that computer settings for the ATi Radeon cards have been scoped out to produce 7.5 and 100IRE, and also some models of the GeForce 2 cards.


Mark, will DILARD perform the White Balance adjustment for the video inputs that Cliff alludes to?


Also, are there any homebrew instructions for adjusting the Polarizing plates? If its just a setscrew adjustment, I would think it would be straightforward to do with a colorimeter by hand. Warranty issues aside, that is. (I would expect that the warranty would be affected the same either way if its was done by a professional calibrator or by the owner)


Andy K.



------------------

"L T One-Fifty

Did your light guide the wisemen,

to baby Jesus?"
 

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David,


The colorimeter is really good at low light level readings due to one photodetector specifically dedicated to that task. It is more than sufficient for the purposes we are using it for, and reads all the way down to 0 IRE on my projector. In fact, it is used to set the biases (black level) in the Dilard Precalibration Wizard. The black level on my D-ILA reads 0.02 cd/m2 (nits).

Quote:
Mark, will DILARD perform the White Balance adjustment for the video inputs that Cliff alludes to?
Andy, I'm not sure what white balance on the separate inputs that this was referring to, but no, Dilard doesn't adjust them. AFAIK, there are no "input specific" settings any where in the projector! There are only source specific settings, and there are 44 of them. Adjusting each one with test signals that can feed it and an external oscilliscope would take days.


Please read that paragraph again closely. It does not specify that this "white adjustment" for the different inputs is adjusted by Cliff, either, just that they exist. I'm not even so sure about that.
 

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I'm assuming that Cliff's calibration is the same as Dilard in that it doesn't include the whole video chain (i.e., it is only the Pj). Is this correct?


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I'm still confused as to how Dilard establishes the reference voltage during calibration.


For instance, the GeForce maxes out at 700mV. But 100 IRE requires 714mV, doesn't it? So if you use a GeForce video card, you can't really accurately calibrate, can you?


So doesn't the projector end up "close" to calibrated - but, for example, the PC thinks it is sending out 7.5 IRE which is supposed to be 53 mV, but actually the particular video card is sending out 56.3 mV, so the projector ends up being a little off?


Mark, did you use a particular video card which you know can consistently produce a certain absolute voltage reference when commanded to do so? Like perhaps a Radeon? Can a Radeon even do the full 714 mV required for 100 IRE?


Am I missing something obvious here?
 

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The ATI Radeon is probably the best example of a video card that does NOT output the correct voltages that I have seen so far. The ones that I have tested (3 so far) have ranged from over 710 mv for one color to 680mv for another (on the same card) - hardly accurate.


The video card that I now use for calibration puts out textbook voltages and waveforms, from 0 IRE to 100 IRE, with all 3 colors tracking to better than 2%.


Wm
 

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ssands,


I am only calibrating the projector, however I am also calibrating the EVR NTSC and HDTV inputs which are the inputs that will be utilized when using a Y/C source signal from a DVD player or HDTV receiver (Component). The gamma calibration only calibrates the RGB look-up table of the projector. The other inputs work from this table but have a separate calibration for "White Balance" of these inputs. Without calibration the sources running through these inputs will display inaccurate color temperature!


It is completely unnecessary to adjust the area source data for the specific input frequencies (all 44 of them)of the projector. Calibrating all of the inputs on the projector insures that regardless of the source the picture quality (ie. color temperature) will remain accurate. The projector is calibrated using calibrated source signals from a signal generator.
 

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Wm,


I assume you are talking about variance between color channels, which is unusual for *any* video card since I believe they all tend to use a single RAMDAC chip for all 3 color channels. As an ASIC designer myself, I am aware of significant chip-to-chip tolerances, but would not have expected the performance for each channel to differ so much inside the same chip.


The only other point I would add is that many, many people claim the Radeons have the best HTPC performance. So, either you got a bad batch of cards (did you test them when they first came out?), or maybe its a case of being too spec-sensitive. Clearly some variance is not noticable to the eye.


(I wonder, is a poor tracking card any worse for calibration purposes than if you were using that same card for DVD playback?)


BTW, any chance you will divulge which card you are using? http://www.avsforum.com/ubb/smile.gif


------------------

"L T One-Fifty

Did your light guide the wisemen,

to baby Jesus?"
 

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Quote:
By the way, I don't have magical eyes at all. In fact, I use

the colorimeter to "see" things that I can't see at all!
Mark

What is the low light (lux) capability of your colorimeter ?

How accurate on front screens is it tking into account the screen?

How will this handle front projection Dlp?

I was told by my ISF guy we would have to use the PR650.


DavidW
 

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Mark,


If your G15 has been calibrated professionally, would there be any reason to get Dilard with Optimagery Colorimeter? Is there calibration drift over time?


------------------

Jim Nissen
 
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