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Sony HVR-Z5 / HDR-FX1000
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Old October 11th, 2009, 07:19 PM   #1
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Can I Adjust Video Gain AGC Sensitivity

In Auto mode, my SONY Z5U raises the gain unnecessarily. On the first wedding we shot, the camera kicked the gain up to over 20dB even when using my 50 watt light, because the backgrounds were dark (guests arriving at night). I adjusted the AGC limit to 6dB, but then the camera still quickly kicks it up to 6dB when it is not needed, and on the rare occasion that the scene actually requires a gain of 12dB, it can't go that high because I set the linit to 6dB. Is there any way to make the Auto Gain Control less sensitive? In other words in full auto mode I don't want the camera to raise the gain unless the scene is darker.
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Old October 11th, 2009, 08:53 PM   #2
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DELETED -operator error in response. Sorry!
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Old October 12th, 2009, 10:24 AM   #3
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If you set the AGC, that should do what you need, not sure what is happening. I shoot with mine set at 9dB and it works out well.

Last edited by Jeff Harper; October 12th, 2009 at 11:11 AM. Reason: Additional comment
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Old October 12th, 2009, 10:50 AM   #4
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Just shoot in manual and call it a day. There is no other way to adjust the gain unless you manually change the AGC limit.
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Old October 12th, 2009, 09:55 PM   #5
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Quote:
Originally Posted by Stephen Cavaseno View Post
Is there any way to make the Auto Gain Control less sensitive?
Sure. Just play around with AE SHIFT. Page 71.

But Jeff's right. Set AGC LIMIT to 9, then set your three manual gain levels to 12, 15 and 18. Keep the switch on the L position by default. Then if you find you need more gain when you're in AUTO, hit the gain button and you can ratchet it up as necessary, then go back to AUTO for the next shot.

Make sure HYPER GAIN is OFF.

And you can do all these things together; it should take care of your problem.
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Old October 12th, 2009, 11:04 PM   #6
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I should submit that I used to complain about the camera's having a grainy look in low light but the issue was I was not using the cam properly. Since lowering the AGC, I have found a dramatic improvement in my images. If 9db isn't enough I use more light (my problem was usually during dark receptions) or I get as close to subject as possible. If those things don't work or are not possible then I ratchet the gain up to 12db and that works out fine also.
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Old October 16th, 2009, 12:52 PM   #7
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Also when light levels drop keep to wide-angle Jeff. You can film in one third the light at wide than in tele as the lens loses a good solid 2 stops as you zoom.
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Old October 16th, 2009, 12:54 PM   #8
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Thanks Tom, learned that pretty quickly!
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Old October 22nd, 2009, 11:50 AM   #9
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What I like to do when I want to control the gain manually, is set the gain limit to 0db and set the AE Shift to -5, set the three manual gain switches to 3, 6, and 9. This gives me 5 switchable settings.
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Old October 22nd, 2009, 12:06 PM   #10
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Tim, I forgot about the AE shift...can you remind me what it does and how it's used? I had played with it a few times and forgot about it for some reason...
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Old October 22nd, 2009, 12:11 PM   #11
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AE shift can be quite useful and I often have my unattended second camera running in full auto with a gain shift dialled in. Say I'm filming the speeches, bottom half of the frame is people, top half is white wall. In auto the camera woould under-expose the people, so I dial in +1.5 stops and all is well - the people brighten up and the wall goes white.

I can't lock the exposure because a) it's an unattended camera and b) the speeches might last an hour and light levels can change hugely in that time.

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Old October 22nd, 2009, 12:51 PM   #12
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Thanks Tom. I also found an old thread where we discussed this...it seems I'm pulled so many directions that sometimes new info gets discarded before I have a chance to use it..
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Old October 22nd, 2009, 04:01 PM   #13
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Tom explained it better than I could have Jeff. But I use AE shift with exposure set to manual and gain set to auto. If the auto gain goes from -3 to 0db and I don't want it too I can hit AE shift and get it back to -3....unless there's not enough light.
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Old October 23rd, 2009, 12:16 AM   #14
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Thanks Tim!
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Old October 23rd, 2009, 01:36 AM   #15
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Quote:
Originally Posted by Tim Akin View Post
I use AE shift with exposure set to manual.
Tim's right, and I've used AE shift in combination with manual exposure when shooting on a dull day in snow. Generally cameras will under-expose in such conditions - the snow will go grey and people will look far too dark.

It goes like this. Dial in an AE shift of +1.5 stops, say. Now lock the shutter speed, w/bal, NDs and gain. Whenever you hit the iris button the camera will go back to auto and give you a reading. Second touch of that button locks in the new reading, and of course you always have fine adjust of this new setting under the iris wheel.

It works well. You're in manual (important) but you're not having to open up lots each time you 'ask the camera'.

tom.
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