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Old November 5th, 2006, 02:39 AM   #1
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Lens resolution and other tests before buy

Just about ready to buy a 101 or 111...I'll see how the $ go.

Before I do so it's important I do some tests on [hopefully] the camera i am going to buy. Things like checking for dead pixels and lens resolutions etc.

The agent here in Jakarta tells me their warrantee covers labour for one year, but not parts and the nearest major service center is Singapore so I don't want any complications after shelling out for the camera.

Do you guys have any special tests you would carry out to ensure this gem is as it should be.

Any advice is appreciated. Thx
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Old November 6th, 2006, 02:31 AM   #2
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yeah. check for split screen. shoot as much test footage as the dealer will allow and study it.

also be sure to test audio. there have been a few qc audio issues.

obviously, buy the same camera you test.
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Old November 6th, 2006, 09:07 AM   #3
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Also, make sure you have a "A" upgrade camera - I'm sure most cameras available have the upgrade, but check for the "A" sticker on the bottom of the camera just to be sure.

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Old November 6th, 2006, 09:26 AM   #4
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And don't worry about dead pixels.

Masking them out is very easy!
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Old November 7th, 2006, 09:02 PM   #5
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Thx folks. I'll let you know how it all goes.

Brian - what do you mean by split screen?

Whats the low light capabilities like on the 101e
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Old November 8th, 2006, 03:55 AM   #6
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Quote:
Originally Posted by Geoff Jak
Thx folks. I'll let you know how it all goes.

Brian - what do you mean by split screen?

Whats the low light capabilities like on the 101e
I forget the technical explanation but many units were/are? plagued by the dreaded SSE. The image is divided right down the middle. eg a shot of a blue sky MIGHT show two shades of blue. very annoying. but if the camera is properly calibrated BY THE FACTORY, it shouldnt happen.
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Old November 8th, 2006, 04:13 AM   #7
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Quote:
Originally Posted by Miltos Pilalitos
And don't worry about dead pixels.

Masking them out is very easy!
If there's a lot of them, or even a few that are closely spaced, I would worry about them. Masking makes them less obvious, but it doesn't repair them.

Regards,

Richard
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Old November 8th, 2006, 04:49 AM   #8
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Yes, I would worry about the dead pixels if I were you. I know that it's a hazard of CCD technology etc. etc. but many users on here (including myself) have had a lot of trouble. In my case, properly masked dead pixels popped up again later in a shoot.
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Old November 8th, 2006, 06:16 PM   #9
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Ok, sounds like I had better keep a sharp eye out for this potential problem -dead pixels.
I am wary of buying here [in Jakarta where i live] as they have told me the warrantee covers labour only for the first year, not parts, so if there is a problem with dead pixels re occurring as Antony said this is going to be a big problem. I wonder what percentage of buyers have had dead pixel problems?
And it would be great to know if the dead pixel problem reduced significantly after a particular serial number - ie, the problem was fixed. Anyone know about that?

Why do pixels fall down dead anyway? When you do a "fix" on them, are they really corrected or just disguised? What is masking of a pixel?
Antony, when you said "properly masked dead pixels popped up again later in a shoot" can you tell me why they would appear. Are they the same dead pixels tat you masked before? or new dead ones?

Thx Brian, I shoot a screen or wall in front of me with a consistent colour and do the sky as well. I remember hearing about this a year ago. I hope it is no longer an issue.

John...I'll be sure to check it has the A upgrade sticker on the base.
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Old November 9th, 2006, 10:33 AM   #10
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[QUOTE=Geoff Jak]I wonder what percentage of buyers have had dead pixel problems?

Quite a few. I have had them twice now.


"And it would be great to know if the dead pixel problem reduced significantly after a particular serial number - ie, the problem was fixed."

I don't think this is the case. For whatever reason, the CCD's on the JVC seem to be a bit more sensitive to gamma rays than other cameras.

"Why do pixels fall down dead anyway? When you do a "fix" on them, are they really corrected or just disguised? What is masking of a pixel?"

Because it's an HD camera, there a many hundreds of thousands of a sensors packed onto a tiny chip. Sunspots, x-ray machines, gamma ray, and other atmospheric conditions all can cause dead pixels. They can happen to any CCD camera.

WHen you fix a dead pixel, it's not fixed or removed, it's 'masked' - which means that the computer searches out the dead pixel then clones it with a pixel next to the dead one. It has been suggested that you leave the camera on for 15 minutes at least to let the pixels 'heat up' before doing the procedure. You may also want to jack up the gain and use a lot of light.

I doubt Anthony's dead pixel came back, but rather that another one close to it failed.

The main trouble with these dead pixels is that is very hard to spy them in the viewfinder when shooting. It's only when you get it home and put in on a big screen that you see the horrible dead pixel. This happened to me this weekend.

So, before you go out to shoot, I'd advise that you let the camera warm up and then view the image through a large HD monitor to double check that there is no dead pixels - It's what I'll be doing from now on. Hope this helps -
john
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Old November 9th, 2006, 10:30 PM   #11
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good advice, thx John
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Old November 10th, 2006, 05:59 AM   #12
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[QUOTE=John Vincent]
Quote:
Originally Posted by Geoff Jak
So, before you go out to shoot, I'd advise that you let the camera warm up and then view the image through a large HD monitor to double check that there is no dead pixels - It's what I'll be doing from now on. Hope this helps -
That would be the best thing to do - yet it isn't always possible to do (when shooting on location e.t.c.

Even then dead pixels aren't that much of a worry. The pixel masking only changes the value of that pixel with the average of the surrounding pixels. Easy enough to reproduce that in post...

Depending on your NLE you might have to search a bit on how to do it, but the operation is simple in nature. Perhaps I'll write a small app for that one day (If no one else has beaten me to it...).
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Old November 10th, 2006, 12:31 PM   #13
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[QUOTE=Werner Wesp]
Quote:
Originally Posted by John Vincent
Even then dead pixels aren't that much of a worry. The pixel masking only changes the value of that pixel with the average of the surrounding pixels. Easy enough to reproduce that in post...
I'm not so sure about this Werner - for a long day's worth of shooting, you could have hours of footage with a glaring spot in the middle of it (it's always in the middle!).

True, the spot won't move and it is something aftereffects could handle fairly easily, it would still add the time to spot/cover-up the pixel, then the rendering time - which in my computer's case would be very long indeed.

If you had to repeat this many times over the course of a feature length film, or you needed quick turn-around time, it would get annoying very quickly - Any time you can avoid rendering, the better IMHO.

We just shot a day's worth of footage that has a big old dead pixel right in the middle of the screen. It's almost easier to re-shoot than go through the headache of fixing it. Won't kill a shot if it's beautiful or once in a life time shot, it's doable.... Otherwise, a big pain.

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Old November 10th, 2006, 11:00 PM   #14
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Antony, sorry to hear about your reoccurring problem with dead pixels. But it might be safe to say that it's maybe more rare than common. Or at least less common for critical shots or this place would be a zoo and JVC up to their eyeballs in ****. And thats just not been the case.

I have had dust attach itself to my lens during a shoot doing far worse than a dead pixel. But, if you run into this type of problem more often then not, you might consider selling the camera, spending more money (likely) and taking your chances with a different unknown (not directed at you John, just to buyers in general). Only people that spend over 100K never have to worry about these type of things... or don't they.

Question:
Do the higher $ cameras even have auto sensing / auto masking dead pixel correction? Pure curiosity here, I personally have no idea how other cameras or manufacturers currently deal with this, as I didn't have to outlay that kind of cash for our HD100 comparatively. I'm not making excuses for anyone, but maybe we should determine if it's even in or out of their control before going to work on JVC with a blow torch and a pair of pliers (God I love Pulp Fiction).

More times than not you are going to find a dead pixel soon enough to correct the problem (on the camera and in post), and with any luck life goes on - you live to shoot another day. This is so minor to all the other things that can and do go wrong.

Happy coding Werner! ;)
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Old November 11th, 2006, 07:50 AM   #15
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Hi John,

It obviously isn't what anyone wants, but you just need to render that 1 time, I suggest configuring a filter in your NLE that does just that, and only use that filter with the final render. Besides, It should be a 'fast' filter - it isn't quite as invasive as (say) color correction...

Still, I'd prefer also not to have no dead pixel, but if it happens, I wouldn't be that worried to reshoot straight away. 1 day of shooting is usually just 2 or 3 minutes of actual finished footage (at the very most, usually it's even less), so rendering that out with 1 extra filter that won't affect the quality is okay for me...
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