AGC

Wayne Dear · October 17th, 2010, 08:23 AM

I am still waiting on Sony to reply back to my phone call last week, on my other topic, but since playing with this camera is it just me or the AGC - Auto Gain Control adds way to much gain than it should?

I dont use Auto anymore, I have become adapted to setting my controls manually, but if for some reason I need a quick Auto look at a picture to see what it comes up with, I find that the camera adds to much gain, as when back at home in production on some test clips I did, compared to manual, there is way more noise on the Auto picture, and none that you could pick unless you know what your looking at in manual controls.

So I turned my AGC to 0 and the auto shots improved so much it makes me wonder why it over compensates.

I have been shooting alot of my shoots now like a reception with this camera at 0-3db and finding my results are coming out really nice, except for my flash issues of causing my footage to pixelate, but thats on the other topic.

Any others have issues with there AGC on this camera?

Cheers

Lou Bruno · October 17th, 2010, 12:21 PM

Go into the Menu and place the AGC no higher than 12db or better yet 9db. This can only be set in the menu as it is a limitation.

NOW..... When you engage the AGC, it will not produce as much grain. Right now, you have it set all the way up to 18db by DEFAULT. OUCH! YIKES!!

Even well lit areas tend to have shadows and dark areas. The AGC is then pumping up the grain in those areas thus ruining your exposure with grain.

Wayne Dear · October 17th, 2010, 09:34 PM

Ya I turned mine down to 0, cause I hate noise, I change it to 3 though and will see what results it gets.

Laurence Kingston · October 19th, 2010, 12:29 PM

The AGC on Sony cameras is calibrated for the Sony mics that come with the camera and these are low output mics. Put another mic on there and the chances are that it will be a louder mic and that the AGC will overly compress the audio. I switched to another mic, then switched back to the stock mic for this very reason.

Dan Crowell · October 19th, 2010, 05:06 PM

Wayne, it sounds like you figured out the AGC. Me personally, I try to never use the gain ever; unless you absolutely have no other option. That being said, the Z7 & S270 produces a very clean HD image at +3 and if necessary you can go as high as +6. Instead of using the gain try shooting in 30p or 24p and lower the shutter speed to match the frame rate or if your shooting with the S270 turn it off for shooting in very dark areas. I've shot extensively with both cameras and I know I can get some very nice low light images out of it without using the gain. On the S270 the shutter switch is on the front of the camera body below the lens. On the Z7 you'll have to hit the shutter button and then scroll through the menu select wheel to change the settings.

Laurence Kingston · October 19th, 2010, 08:54 PM

OK, I'm on the same page now. Video noise wise, I still see noise at 0db. -3 or -6 and it goes away. I try not to use gain because even though Neat Video cleans the noise pretty well, it takes forever to render.

Wayne Dear · October 25th, 2010, 05:55 AM

I havnt tried the progressive, all new to me on the Z7, I did read somewhere though progressive isnt good if you want to do a slow motion clip? I still dont totally understand it, after reading extensively on it, yet then I read progressive is the way to go for low light shoots? I prolly get a little confused as there are so many topics about it now and most of them have different views on progressive over interlaced.

On the gain, what setting on z7 is classed as off? I am imagining 0 being off under my logic, but then im probably wrong as it goes as far as -6 lol.

Anyways I did get a very good result with the 1080i @ 50 and gain set at 0,3 & 6 on Wedding I just did on Saturday, a little noise still, I use trapcodes Denoiser, and yeah, it takes forever to render, but like all the rendering I do, when I sleep my CPU is rendering.

Used the 3 second slow motion as well when I was with groom on the Golf Course, came out really nice :)

Cheers

Greg Laves · October 27th, 2010, 08:27 PM

I never turn on the auto grain function. I have my L, M & H manual settings tuned to -6 db, 0 db and 6 db. It seems to work well for me. I am in 60i land and I find that shooting in 60i gives the best slo-mo results for me. I think the edit system has more information to work with when interpolating the data and it results in the smootest results.

October 17th, 2010, 08:23 AM	#1
Wayne Dear Regular Crew Join Date: Dec 2009 Location: Albury NSW Posts: 46	AGC - Functioning Correctly? I am still waiting on Sony to reply back to my phone call last week, on my other topic, but since playing with this camera is it just me or the AGC - Auto Gain Control adds way to much gain than it should? I dont use Auto anymore, I have become adapted to setting my controls manually, but if for some reason I need a quick Auto look at a picture to see what it comes up with, I find that the camera adds to much gain, as when back at home in production on some test clips I did, compared to manual, there is way more noise on the Auto picture, and none that you could pick unless you know what your looking at in manual controls. So I turned my AGC to 0 and the auto shots improved so much it makes me wonder why it over compensates. I have been shooting alot of my shoots now like a reception with this camera at 0-3db and finding my results are coming out really nice, except for my flash issues of causing my footage to pixelate, but thats on the other topic. Any others have issues with there AGC on this camera? Cheers

October 17th, 2010, 12:21 PM	#2
Lou Bruno Go Cycle Join Date: Dec 2001 Location: Huntington, NY Posts: 815	Go into the Menu and place the AGC no higher than 12db or better yet 9db. This can only be set in the menu as it is a limitation. NOW..... When you engage the AGC, it will not produce as much grain. Right now, you have it set all the way up to 18db by DEFAULT. OUCH! YIKES!! Even well lit areas tend to have shadows and dark areas. The AGC is then pumping up the grain in those areas thus ruining your exposure with grain. __________________ Lou Bruno

October 17th, 2010, 09:34 PM	#3
Wayne Dear Regular Crew Join Date: Dec 2009 Location: Albury NSW Posts: 46	Ya I turned mine down to 0, cause I hate noise, I change it to 3 though and will see what results it gets.

October 19th, 2010, 12:29 PM	#4
Laurence Kingston Major Player Join Date: Aug 2004 Location: Clermont, FL. Posts: 941	The AGC on Sony cameras is calibrated for the Sony mics that come with the camera and these are low output mics. Put another mic on there and the chances are that it will be a louder mic and that the AGC will overly compress the audio. I switched to another mic, then switched back to the stock mic for this very reason.

October 19th, 2010, 05:06 PM	#5
Dan Crowell Regular Crew Join Date: Oct 2010 Location: Brick, New Jersey Posts: 47	Wayne, it sounds like you figured out the AGC. Me personally, I try to never use the gain ever; unless you absolutely have no other option. That being said, the Z7 & S270 produces a very clean HD image at +3 and if necessary you can go as high as +6. Instead of using the gain try shooting in 30p or 24p and lower the shutter speed to match the frame rate or if your shooting with the S270 turn it off for shooting in very dark areas. I've shot extensively with both cameras and I know I can get some very nice low light images out of it without using the gain. On the S270 the shutter switch is on the front of the camera body below the lens. On the Z7 you'll have to hit the shutter button and then scroll through the menu select wheel to change the settings.

October 19th, 2010, 08:54 PM	#6
Laurence Kingston Major Player Join Date: Aug 2004 Location: Clermont, FL. Posts: 941	OK, I'm on the same page now. Video noise wise, I still see noise at 0db. -3 or -6 and it goes away. I try not to use gain because even though Neat Video cleans the noise pretty well, it takes forever to render.

October 25th, 2010, 05:55 AM	#7
Wayne Dear Regular Crew Join Date: Dec 2009 Location: Albury NSW Posts: 46	I havnt tried the progressive, all new to me on the Z7, I did read somewhere though progressive isnt good if you want to do a slow motion clip? I still dont totally understand it, after reading extensively on it, yet then I read progressive is the way to go for low light shoots? I prolly get a little confused as there are so many topics about it now and most of them have different views on progressive over interlaced. On the gain, what setting on z7 is classed as off? I am imagining 0 being off under my logic, but then im probably wrong as it goes as far as -6 lol. Anyways I did get a very good result with the 1080i @ 50 and gain set at 0,3 & 6 on Wedding I just did on Saturday, a little noise still, I use trapcodes Denoiser, and yeah, it takes forever to render, but like all the rendering I do, when I sleep my CPU is rendering. Used the 3 second slow motion as well when I was with groom on the Golf Course, came out really nice :) Cheers

October 27th, 2010, 08:27 PM	#8
Greg Laves Major Player Join Date: Nov 2007 Location: Corpus Christi, TX Posts: 640	I never turn on the auto grain function. I have my L, M & H manual settings tuned to -6 db, 0 db and 6 db. It seems to work well for me. I am in 60i land and I find that shooting in 60i gives the best slo-mo results for me. I think the edit system has more information to work with when interpolating the data and it results in the smootest results.