Is gain "BAD" for the CCDs? at DVinfo.net

Go Back   DV Info Net > JVC ProHD & MPEG2 Camera Systems > JVC GY-HD Series Camera Systems

JVC GY-HD Series Camera Systems
GY-HD 100 & 200 series ProHD HDV camcorders & decks.


Reply
 
Thread Tools Search this Thread
Old August 2nd, 2006, 05:45 PM   #1
Major Player
 
Join Date: Apr 2006
Location: Pacific NW
Posts: 431
Is gain "BAD" for the CCDs?

This is something I've always wondered.

Is gain (-9, -18 etc..) bad for the camera ccd's?

Does it burn them out faster like a candle burning twice as bright?

Or is it just a DSP amplification of the existing signal?

On another note, my HD100U-A just started showing 2 hot pixels when
the gain is turned on. A few weeks ago this was not the case.
Mark Silva is offline   Reply With Quote
Old August 2nd, 2006, 07:29 PM   #2
Trustee
 
Join Date: Dec 2004
Location: Lipa City Batangas, Philippines
Posts: 1,110
Hi Mark. The gain is applied to the signal AFTER the CCD, before the analogue to digital conversion (therefore before any DSP involvement), so it has no effect on the CCD at all. The main downside to applying gain is that the noise in the signal is amplified too and this is why a low light image with high gain is usually very noisy.

Shame about the dead pixels. It's very worrying that this is happening to some cameras after they have been in use for a while.

Richard
Richard Hunter is offline   Reply With Quote
Old August 3rd, 2006, 12:05 AM   #3
Regular Crew
 
Join Date: May 2006
Location: Chicago, IL
Posts: 114
I just shot lightning and noticed split screen at 9db and 18db....after a day getting it back refirmware-ated :). Not like i actually care for gain, nor ever care to use it, but i was wondering if I'm still supposed to get split screen while it already being calibrated?

Another note is that I noticed a white pixel on 18 gain

Here is what both looked like....

BTW my intentions were not to look for this, I noticed it when I got back.
Attached Thumbnails
Is gain "BAD" for the CCDs?-split-screen.jpg   Is gain "BAD" for the CCDs?-hotpixel18db.jpg  

Matt Setnes is offline   Reply With Quote
Old August 3rd, 2006, 11:39 AM   #4
Major Player
 
Join Date: Mar 2006
Location: Sherman Oaks, CA
Posts: 471
In your split screen jpeg, the SSE is obvious, however, in your hot pixel jpeg, the SSE is almost undetectable, but it's the same shot.

My question is, did the SSE only last a couple of frames? If so, that is normal. The DSP need more time to calibrate in low lighting conditions. Had the SSE stayed that way the entire time, then you would have an issue.
Scott Jaco is offline   Reply With Quote
Old August 3rd, 2006, 03:42 PM   #5
New Boot
 
Join Date: Apr 2006
Location: Orange County, CA
Posts: 16
I was shooting the other night in practically no light and finaly managed to make the split screen appear after so many months of trying. It only stayed for about 5 minutes until my unit warmed up then it went away. I also had the gain set to 18db. What is surprising to me is Dashwoods "low-light" scene file if actually more affective then 18db gain. What I was doing half the time( just as a test. none of this footage is being used for anything other then my home tests) was using the "low-light" scene file and the cranking the gain up to 18db and getting an image that could easily be blown out. And it was nearly pitch black out. Just thought I'd share that even though the last half is kind of irrelevant.
Matthew McKane is offline   Reply With Quote
Old August 3rd, 2006, 04:56 PM   #6
Regular Crew
 
Join Date: May 2006
Location: Chicago, IL
Posts: 114
Well it doesn't bother me, only the fact that last week I shot some night footage, but it involved a little bit more lighting, although i only used 12db at max. Below I have SSE from before it was services at 12db, then another SSE at 18db. So seems like i'm getting more than just a couple frames. I noticed though that it'll only happen in certain lighting situations.

The bad part about this is just noticing it. Personally if I'm shooting something, I prefer not to use gain at all, but when the time comes and I'm shooting a low light event, there will be no way in viewing this problem unless viewing it on a different monitor. So if I bought this A version and redid the firmware, what's the point in getting it serviced again if this problem will continue in unpredictable situations. I'm sort of dissapointed because at first it didn't bother me as I heard it mostly occurs at 18, but seeing how 12db is mostly suitable in really extensive low light conditions and still getting it, just saddens me, especially since it happened after being reupgraded.

All in all for all the prospective buyers out there, this problem is very minor, especially from a filmmaker's view. Gain shouldn't be used period in achieving a scene's look, Although, any blair witch predecessors might be wary of this problem.

I'm very curious about this issue and wondered if something is up JVC's sleeves for the HD110, whether or not that's why the AB promo continues until the end of august. My guess is the SSE is eliminated in the HD110? because why offer the promo for the HD100 and not 110? That's just my question. Anyways, that's my say for the day.
Attached Files
File Type: mov SSE.mov (4.45 MB, 110 views)
File Type: mov SSE2.mov (1.93 MB, 100 views)
Matt Setnes is offline   Reply With Quote
Old August 3rd, 2006, 05:01 PM   #7
Major Player
 
Join Date: Apr 2006
Location: Pacific NW
Posts: 431
-12db is to noisy imo.

I too never shoot any real jobs with gain.

But I have found -9db to be permissable as its pretty clean.

The cleanest -9db of any camera I've seen.
Mark Silva is offline   Reply With Quote
Old August 3rd, 2006, 05:11 PM   #8
Regular Crew
 
Join Date: May 2006
Location: Chicago, IL
Posts: 114
oops. Typo, I meant 9db. 12 is pushing it. Do you get any LCD flickering when using gain?
Matt Setnes is offline   Reply With Quote
Old August 4th, 2006, 01:02 AM   #9
Major Player
 
Join Date: Apr 2006
Location: Pacific NW
Posts: 431
None at all.

Are you seeing flicker?
Mark Silva 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 > JVC ProHD & MPEG2 Camera Systems > JVC GY-HD Series Camera Systems

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 04:52 PM.


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