AVS Forum banner

1 - 20 of 21 Posts

·
Registered
Joined
·
249 Posts
Discussion Starter #1
Ok, I just don't understand this. Can someone explain this to me. I don't get how if all epson projectors or any projector for that matter is made with the same exact parts and built the exact same way how is it that each individual projector will not calibrate the same? I just don't understand how that is possible.
 

·
Registered
Joined
·
12,404 Posts
 http://www.avsforum.com/avs-vb/showp...70&postcount=1

"Electronic component tolerances used in consumer TVs and source components are very loose and imprecise (+/- 10% or worse). Because these tolerances are so imprecise, two samples of TV can come off the same assembly line and require very different picture settings to look near the same."
 

·
Premium Member
Joined
·
2,245 Posts

Quote:
Originally Posted by jhunt17 /forum/post/19516933


Ok, I just don't understand this. Can someone explain this to me. I don't get how if all epson projectors or any projector for that matter is made with the same exact parts and built the exact same way how is it that each individual projector will not calibrate the same? I just don't understand how that is possible.

Let's see, where to begin



Different screens (size and material)


Parts have a tolerance of around +/- 10%. Therefore, imagine everyone's parts being different than yours by +/- 10% in every control where a single click can make all the difference. PJ's and all other equipment are not made to military specs.


Different source components can make a HUGE difference.


Different room conditions


The list goes on and on. Hope this helps!
 

·
Registered
Joined
·
3,842 Posts

Quote:
Originally Posted by jhunt17 /forum/post/19516933


Ok, I just don't understand this. Can someone explain this to me. I don't get how if all epson projectors or any projector for that matter is made with the same exact parts and built the exact same way how is it that each individual projector will not calibrate the same? I just don't understand how that is possible.

Different environments affect image quality. Varying parameters like different colored walls, floors, ceilings, furniture, different lighting, screen size and distance can all impact perceived contrast and color drastically.


Also, this changes more as the bulb age.


Therefore, every projector needs to be calibrated for the specific environment it is in.
 

·
Registered
Joined
·
3,314 Posts
Even high end broadcast and film equipment requires individual calibration and setup its not just consumer level.


Think of cars: they require wheel balancing and alignment on an individual basis irrespective of model.
 

·
Registered
Joined
·
249 Posts
Discussion Starter #6
I understood the source components and room conditions, but just didn't think that the components that made up the projector could have that much of a different result. So in other words at the factory all they do is slap the components together and don't bother to tune it. Is that about right?
 

·
Registered
Joined
·
3,866 Posts
Each lamp varies considerably even over it's own lifetime or if you change the lamp power (mine was completely different in high power, with more red for example). Add to this the tolerances in the other components, plus the room, then you see why each projector has to be calibrated in situ. Even getting it done at say 200 hours won't mean it will stay calibrated for the rest of it's life, plus if you change the lamp then it could be completely different. With JVCs like mine, the gamma tends to flatten/lower over time making the image look flat, so detailed adjustments are needed to set it right again.
 

·
Registered
Joined
·
12,404 Posts

Quote:
Originally Posted by Kelvin1965S /forum/post/19521260


Each lamp varies considerably even over it's own lifetime or if you change the lamp power (mine was completely different in high power, with more red for example). Add to this the tolerances in the other components, plus the room, then you see why each projector has to be calibrated in situ. Even getting it done at say 200 hours won't mean it will stay calibrated for the rest of it's life, plus if you change the lamp then it could be completely different. With JVCs like mine, the gamma tends to flatten/lower over time making the image look flat, so detailed adjustments are needed to set it right again.

makes a compelling argument for getting your own calibration equipment and calibrating as many times as needed...
 

·
Registered
Joined
·
3,314 Posts

Quote:
Originally Posted by PlasmaPZ80U /forum/post/19521269


makes a compelling argument for getting your own calibration equipment and calibrating as many times as needed...

I generally agree with this.
 

·
Registered
Joined
·
283 Posts
Hi,


I just wonder what the manufactures tolerance are when it comes to the display panel themselves?


Plasma - Phosphor tolerances

LCD - Filter tolerances, backlight tolerances

LED - Filter, backlight tolerances


Are they within 20%?
 

·
Registered
Joined
·
3,852 Posts
An Epson dealer training I attended included stating their official panel alignment tolerance for their '3LCD' light engines. They pass chip alignment errors as great as +/- an entire pixel between the red, green, and blue imagers. Epson licenses the use of their light engines and technology to all the other companies that feature the '3LCD' logo.
 

·
Registered
Joined
·
3,852 Posts
Quote:
Originally Posted by delphiplasma
Hi,


I just wonder what the manufactures tolerance are when it comes to the display panel themselves?


Plasma - Phosphor tolerances

LCD - Filter tolerances, backlight tolerances

LED - Filter, backlight tolerances


Are they within 20%?
How about if you just ask them directly and report back to us what they tell you? Why wonder when you can at least try to get the information from the horse's mouth? For me, the issue is really whether or not loose tolerances can be compensated for in the calibration process. Tight tolerances cost a lot more money to manufacture. I was reading about a grade 1 broadcast monitor recently that cost almost $8k for a 17" LCD. Even professional monitors require periodic calibration, and they don't copy settings from other displays.
 

·
Registered
Joined
·
249 Posts
Discussion Starter #14
Well if all they do is throw the parts together how can any projector get to be thx certified? Doesn't it have to be calibrated to some extent? If not wouldn't my thx setting on my epson 8500ub be worthless?
 

·
Registered
Joined
·
5,336 Posts

Quote:
Originally Posted by jhunt17 /forum/post/19528970


Well if all they do is throw the parts together how can any projector get to be thx certified? Doesn't it have to be calibrated to some extent? If not wouldn't my thx setting on my epson 8500ub be worthless?

Understand that the manufacturer pays a fee and submits a sample or samples to THX for testing. If it passes, they get to put the THX logo on the product. THX does not publish the specific things it tests for in most cases, only general statements about its goals. There are some things about a factory calibration (if it had to be done for the THX cert) that simply won't be valid once the product is installed. For instance, a THX receiver's amps could be level-matched at the factory so they are all putting out the same power at reference level. Once in the installed location, differences in speaker placement, type, and aiming all mean that the levels have to be rebalanced. The same goes for your projector. Its installed environment has a huge effect on its performance and the display must be calibrated or at least checked for it.


The THX settings on displays, from what I've seen and read, serve as a quick way to change from daytime to nighttime viewing settings. They still should be calibrated for best results in the installed environment.
 

·
Registered
Joined
·
3,852 Posts

Quote:
Originally Posted by jhunt17 /forum/post/19528970


Well if all they do is throw the parts together how can any projector get to be thx certified? Doesn't it have to be calibrated to some extent? If not wouldn't my thx setting on my epson 8500ub be worthless?

Why the drama? Of course they don't just "throw the parts together." How silly. Every manufacturer has their own internal methods for quality control, with their own tolerances for what they consider sales worthy performance. THX provides a consulting service to help design, and then verify, compliance with a substantial list of performance criteria. The pre-installed and factory adjusted THX settings are just another picture mode preset. It is the factory preset that will give the best results out of the box. As others have said, additional alignment will be needed once it's installed in the system, to compensate for all the variables listed.
 

·
Registered
Joined
·
249 Posts
Discussion Starter #17
No drama, just a simple question. I wanted to know how they do things. I asked this because how could someone review the product correctly if none of them have the same quality picture? So all presets are basic calibrations from the factory and all should pretty much look the same coming from the factory. Then minor corrections need to be made to allow for your particular room. Is that correct?
 

·
Registered
Joined
·
3,866 Posts
If you read the decent reviews like those done by Phil Hinton over on AVforums you'll see that they show the out of the box calibration and then they calibrate as best as the projector's controls allow (ie they don't use an external CMS, etc to correct oversaturation for example). Therefore these reviews are based on watching a calibrated picture. This sometimes means that a projector is viewed at much lower than the manufacturer's claimed lumens output as this can be exagerated if measured (for the specs) at a high colour temp for example, but at least it's a level playing field.


FWIW I think that the THX setting isn't worth a great deal on any projector due to the lamp drifting. For the same reason I don't think having a projector calibrated by the dealer is worth doing. You need to put at least 100 hours on the lamp to let it stabilise and incase of early failure (you won't get the cost of your wasted ISF calibration back if the projector fails early on).
 

·
Registered
Joined
·
5,785 Posts

Quote:
Originally Posted by jhunt17 /forum/post/19528970


Well if all they do is throw the parts together how can any projector get to be thx certified? Doesn't it have to be calibrated to some extent? If not wouldn't my thx setting on my epson 8500ub be worthless?

I believe some are calibrated to certain specs before leaving the factory, but due to these settings varying from unit to unit, it's not accurate to follow someone else's settings even in that case. This is why some calibrators that post settings here post the offsets rather than the settings. Like if his TV came out of the factory with a R-Drive of 50 and his resulting calibration have it at 55, he will post +5 rather than 55 because others with the same unit may have a 45 default setting.
 

·
Guest
Joined
·
867 Posts
I own three completely identical Mitsubishi projectors. Grey is visibly not the same shade of grey if the projectors are setup identically, close but no cigar. I assume it is mainly due to lamps outputting different light, and lamp output varying with age. I suppose color filters might vary or age or get dirty as well.


Calibration with RGB bias and gain maybe pretty coarse anyway so I doubt you would get much difference in calibration with identical projectors using identical screens, maybe a point of two here or there. At least from my experience of having three projectors, may not hold true for a larger sample.


If you are using different screens then calibration could be significantly different. Different screens have significantly different RGB values.
 
1 - 20 of 21 Posts
Top