Dead Pixels in LCD Displays at DVinfo.net

Go Back   DV Info Net > Canon EOS / MXF / AVCHD / HDV / DV Camera Systems > Canon HDV and DV Camera Systems > Canon XL and GL Series DV Camcorders > Canon GL Series DV Camcorders

Canon GL Series DV Camcorders
Canon GL2, GL1 and PAL versions XM2, XM1.


Reply
 
Thread Tools Search this Thread
Old July 28th, 2003, 09:19 PM   #1
Regular Crew
 
Join Date: Jun 2003
Location: Sydney, Australia
Posts: 125
Dead Pixels in LCD Displays

Hello all,

I don’t have a real reason to post this, but since there was someone who asked and is a common problem among LCD screens that affect Cameras as well, here is a little reply post I did in another forum…

Subject:
Dead Pixels in LCD Displays

I bought a new XM2 and as soon I unpacked it I noticed three dead pixels...( I wasn't very happy), but I rang the dealer who sold it to me and he organised a replacement from Canon... no questions asked!

Some manufacturers see “Dead Pixels” differently (mainly with LCD displays), they claim the error rate accounts for some dead pixels and have all different policies regarding them. But they all insist on claiming that you are getting a 1600x1200 pixel monitor (for example), which to me is not true even if only one pixel is dead! So technically they have to replace it and give you a monitor that has the full advertised 1600x1200 pixels all working... right?

In retrospect, does one buy a car with a dead wheel and accepts it? Highly unlikely!

The XM2 is not a toy and thus should be perfect when new... it is (in my opinion) seldom for the camera to create dead pixels after purchasing the camera WITHOUT any dead pixels... it either has or hasn't got dead pixels when manufactured.

I will however point out that a dead pixel is much better than one stuck on a colour especially RED! That is what happened with me... One bright Red pixel, one bright Green pixel and one dead pixel (unlit).

Here is an interesting article about dead pixels in LCD screens if you are interested.

http://www4.tomshardware.com/display/20030319/

Also, one way to test for dead pixels is to generate a few different colours and feed them into the camera (via SD memory card) or shoot them via the lens to see individual pixels if they are dead or permanently lit.

Cheers,
Jack – XM2 User
Jack Robertson is offline   Reply With Quote
Old July 28th, 2003, 09:50 PM   #2
Inner Circle
 
Join Date: Jun 2003
Location: San Jose, CA
Posts: 2,222
>In retrospect, does one buy a car with a dead wheel and >accepts it? Highly unlikely!

That's a bit of an overstatement. Even with cars, you are buying
a particular range of "defects" in the form of manufacturing tolerances. Car manufacturers screen for defects that fall outside of the designed limits. Your new car is not perfect, either.
A dead wheel is a critical defect. A scratch on the chassis will go unnoticed. Likewise, a dead pixel is not a critical defect in the minds of most consumers.

As for LCD panels, it's pretty clear that the market is willing to
accept a particular # of defects although it seems that the manufacturers are trying increase this #. I didn't want to bother returning my first JVC camcorder with one dead pixel in the LCD display for two reasons: 1) it didn't really bother me 2) I know products are shipped with dead pixels and thought the next unit could be the same or worse.

LCD panel manufacturers can ship all of their panels with zero dead pixels, but you will be paying more.
It's clear the manufaturers are trying to reduce their cost of shipping LCD products by shipping slightly defective panels.
Gints Klimanis is offline   Reply With Quote
Old July 28th, 2003, 11:25 PM   #3
Regular Crew
 
Join Date: Jun 2003
Location: Sydney, Australia
Posts: 125
Gints,

I agree with you, that zero dead pixels would cost us more, but in the end it comes down to what the customer is willing to accept.

As you have mentioned it really didn't bother you having one dead pixel, but if you had the problem I had, you might have had a different view.... One Pixel stuck on RED, One Pixel Stuck on Green and one dead... as I said previousy, a dead pixel is better than one stuck on a colour, which is far more annoying and always in your face!

Jack
Jack Robertson is offline   Reply With Quote
Old July 29th, 2003, 02:08 AM   #4
Inner Circle
 
Join Date: Jun 2003
Location: San Jose, CA
Posts: 2,222
Jack,

I'm with you on dead pixels, be they unlit or "stuck". For my first sub $1000 camcorder with a 3.5" flipout LCD, I didn't care. I would have been more upset if my Sony vx-2000 with it's 2.5" flip LCD had a dead pixel, but I still would have accepted it. On an LCD display or TV, I would have less tolerance.

The higher the price, the lower my tolerance. Manufacturers should know this, but obviously, consumers are accepting it.
I've seen $5000 rear projection Tvs with dead pixels on pretty small LCDs. What's up with that? If the return rate were significant, manufacturers would ship with dead pixel ratings and possibly offer discounts that reflect quality of the LCD shipped.
For camcorders, the manufacturers should make it easy for the user to remove and replace the LCD.
Gints Klimanis is offline   Reply With Quote
Old July 29th, 2003, 05:28 AM   #5
Wrangler
 
Join Date: Sep 2001
Location: Northern VA
Posts: 4,298
The cost of using only perfect LCD (or CCD for that matter) would be prohibitive for most users of these consumer/prosumer/entry-level progessional camcorders.

It goes back to the attainable yield in the semiconductor manufacturing process. A For a perfect CCD you would have to produce a chip with 270,000 or more perfect transistors.
__________________
dpalomaki@dspalomaki.com
Don Palomaki is offline   Reply With Quote
Old July 29th, 2003, 08:46 AM   #6
Major Player
 
Join Date: Feb 2003
Location: Jarrettsville, MD
Posts: 353
The yield of perfect 3" and under flat displays is quite high today. Yield is the major factor that prevents or allows a manufacturer to move along to larger sizes. There was a time when the cost of a 3" display was prohibitive because of yield, but those days are long gone.

That doesn't mean less than perfect ones won't show up, but I see no reason not to demand a perfect one.

I don't know what the yield equation is for CCDs. The yield for semiconductor devices in these sizes is pretty high, though.

Will
Will Fastie is offline   Reply With Quote
Old August 1st, 2003, 01:27 PM   #7
Obstreperous Rex
 
Join Date: Jan 2001
Location: San Marcos, TX
Posts: 26,900
Images: 513
Like most other camera manufacturers, Canon provides a gaurantee of 99.97% on the LCD pixels. This means that there might be 3 or 4 dead or hot pixels. Since they're in the LCD display and not in the CCD block, image quality is NOT affected. As inexpensive as this gear is these days, in my opinion a 0.03% tolerance is more than acceptable. If you need 100% firing pixels in the LCD display, you can have them, but they will be in a significantly costlier camcorder than the GL2 or XM2. Hope this helps,
__________________
CH

Search DV Info Net | DV Info Net Sponsors | A Decade (+5) of DVi | ...Tuesday is Soylent Green Day!
Chris Hurd is offline   Reply With Quote
Old August 1st, 2003, 01:43 PM   #8
Major Player
 
Join Date: Feb 2003
Location: Jarrettsville, MD
Posts: 353
Chris, you're right, I wasn't clear. I agree that LCD quality is not a determining factor for camcorders, as it won't affect the camcorder's output. LCD quality on a laptop PC is a determining factor; I, for one, demand that all the pixels work.

The question is whether it is reasonable to expect a CCD to be perfect. The CCD will affect output, so I say it must be perfect. Is it reasonable to make that demand? I think it is because the yield for semiconducter devices sized like CCDs and with similar component counts is extremely high today.

As for getting 270,000 perfect transistors, contemporary CPU chips have millions of transistors. While it might be okay for memory to have defective transistors that can be avoided by using spares, the core circuitry of a processor is either right or wrong. Most CPUs come off the line right; processor yields today are high.

Will
Will Fastie is offline   Reply With Quote
Old August 20th, 2003, 06:53 AM   #9
New Boot
 
Join Date: Aug 2003
Location: Dorset, UK
Posts: 10
Hi all!

I'm new - so after having used this site as a fantastic reference help before buying my XM2 this is my first post!

Got my XM2 (new) last night so haven't had a chance to check it totally although I can already see a stuck/hot pixel (red) just off the centre of the LCD display.

I have read the links to dead/stuck pixel related stuff on this post and elsewhere and I think this is a plain scary situation from the end-user point of view. I understand the argument that imperfect screens still need to be used/sold in the marketplace and there is a place for them, however I feel the heart of the matter is this: regardless of the cost a product containing an LCD screen should be perfect unless info regarding this problem (not uncommon it seems) is freely available from manufacturer to customer prior to purchase.

Most manufacturers do not seem to make this info easily accessible - understandably possible defects are not a great selling point - and after having no luck with documentation or online, currently Canon UK (who told me 99.99% - I haven't done the maths yet) are trying to source something that is actually written down to send me regarding this subject.

I am just coming from the consumer info angle because, like many of us I'm sure, I have had a fair amount of use of LCD screens for quite a while now on computers, cameras and the like and although I have seen this problem before on stuff I don't own, I have never entertained the idea that visible LCD defects would be tolerated in a brand new product.

Don't know about the truth in this, however the idea that Philips are using/will use zero tolerance of dead pixels in screens as a selling point is laudable and seems like a more positive manufacturer response.

I read with glee the advice on one of the posts regarding 'stuck' pixels - on solidly red, green or blue - and the fact they might be gently 'massaged' back to functioning normally using a lens cloth or similar. I love this cam already and can't wait to get home from work to try that - although I might refrain from telling my friends...!
Phil Christopher is offline   Reply With Quote
Old August 21st, 2003, 06:10 AM   #10
New Boot
 
Join Date: Aug 2003
Location: Dorset, UK
Posts: 10
Just to update - tried the 'pixel massage' theory, but no joy. Worth a shot I suppose...

Phil
Phil Christopher is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > Canon EOS / MXF / AVCHD / HDV / DV Camera Systems > Canon HDV and DV Camera Systems > Canon XL and GL Series DV Camcorders > Canon GL Series DV Camcorders

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 08:56 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network