View Full Version : Can I Adjust Video Gain AGC Sensitivity


Stephen Cavaseno
October 11th, 2009, 06:19 PM
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.

Don Bloom
October 11th, 2009, 07:53 PM
DELETED -operator error in response. Sorry!

Jeff Harper
October 12th, 2009, 09:24 AM
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.

Rob Morse
October 12th, 2009, 09:50 AM
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.

Adam Gold
October 12th, 2009, 08:55 PM
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.

Jeff Harper
October 12th, 2009, 10:04 PM
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.

Tom Hardwick
October 16th, 2009, 11:52 AM
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.

Jeff Harper
October 16th, 2009, 11:54 AM
Thanks Tom, learned that pretty quickly!

Tim Akin
October 22nd, 2009, 10:50 AM
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.

Jeff Harper
October 22nd, 2009, 11:06 AM
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...

Tom Hardwick
October 22nd, 2009, 11:11 AM
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.

tom.

Jeff Harper
October 22nd, 2009, 11:51 AM
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..

Tim Akin
October 22nd, 2009, 03:01 PM
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.

Jeff Harper
October 22nd, 2009, 11:16 PM
Thanks Tim!

Tom Hardwick
October 23rd, 2009, 12:36 AM
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.

Rob Morse
October 23rd, 2009, 05:30 PM
Tim/Tom,

Great idea. Sounds like I'm dense but I never thought of using it that way. Like Tim said, it's like getting 5 buttons. Learn something new everyday

Zach Love
November 2nd, 2009, 02:28 PM
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.

Amen. Same with focus. I know I sound like a snob when I say it, but if you want to be a professional and use professional equipment, act like a professional and learn to be smarter than the camera by using full manual.

Jeff Harper
November 7th, 2009, 01:26 AM
I believe that the important thing in run-and-gun shooting is learning where running in full auto will work and where it will not, which comes with time and experience with the camera.

I like to avoid, when possible, recording while changing settings dramtically on the camera. There are times when I have had to quickly change directions that I was pointing the camera to catch an important spontaneous moment which required a whole different range of settings because of lighting or whatever, and in those instances I instantly switch to auto for a starting point.

Ineveitably, shooters I have hired that refuse to run in anything but manual ALWAYS have much footage that will not come close to matching the quality of other cameras running mostly in full auto. There are times when it is NOT advisable to run in manual, I have learned.

Rob Morse
November 7th, 2009, 08:26 AM
You're right Jeff but it has to be controlled and you need to have a good idea of what switching to auto is going to give you. As you said, it comes from experience with the camera. It sounds backward but shooting in manual is the only way you'll learn to shoot correctly in auto.