Auto Gain on 16:9/24 at DVinfo.net

Daniel Black · December 5th, 2005, 01:31 PM

I have been reading many of the threads on this forum and am learing a great deal that is not in the manual so thanks to all. What I have noticed is that most folks are recomending right out the box you should set the gain at or below 0 and not on auto. Unfortunately we have almost finished our principle... and everything we shot was on auto. I never really noticed noise exept when we were really in a dark big room. We came back to shoot the next weekend with loads of lights and this helped tremendously. We shot outside and inside an left it on Auto. Interviews and action shot both in and out. We are going for a "movie" look and so we shot everything in 16:9 at 24 frames. We did white balance checks everywhere and moved lighting around until we liked what we saw, but once again we never adjusted the gain. I have heard others report on noise, is this generally a "grainy" look? I have not really noticed but perhaps our footage could be better, perhaps we are not seeing the best. Can I get some comments on this matter and in the meantime I will play with these settings at 16:9/24 and see what is different at say gain on 0 to -3.

Thanks to All

Kevin Wild · December 5th, 2005, 01:39 PM

There's not much we can say at this point, because we have no way of knowing how everything was lit. If it was all well lit and lit brightly, you'd probably be fine with "auto gain" on. However, don't do it in the future. Gain is DEFINITELY one easily controlled aspect of the camera that you don't want to use unless you absolutely need to. MUCH, MUCH better to light more and keep the gain down.

I once used the auto gain when I first got the XL2 in a concert environment. Even with an on camera light, the footage turned out HORRIBLE. I was calling that button the "auto grain" setting.

For the record, the grain that auto-gain gives you is NOTHING like the film grain you might be going for. Do not confuse the two. Video grain is downright awful and ugly.

Put your gain on 0 or -3 and leave it there forever!

KW

Daniel Black · December 5th, 2005, 02:34 PM

Thanks Kevin. We did light pretty well and thus I think this is why it looks OK. Nevertheless we shot outside on a very cloudy day once and I bet it would have really helped. When we blow this up to big screen is it going to be more noticable? The main problem is we have no real way of getting our subject back to re-shoot. Also, when you set it on auto gain does it alway selected the higher setting. In theory it should put it below 0 if the light is low, isn't that the whole purpose of auto, to give you the best setting automatically? If we are planning to distribute this will these have to be re-shot? As I said before it looks good, but I can't help but wonder... We shot a good bit outside on sunny days too, do you set the gain low then as well?

Joseph Andolina · December 5th, 2005, 02:38 PM

I have a question. Is it better to just stick with the gain at 0 as upposed to
-3 in all lighting situations? I just got done shooting a 5 min. short staying at 0. There were certain scenes (a bar scene) in lower ligthing. But since I wasn't able to use a high-end field monitor, I didn't want to take a chance and change the gain to -3.

Kevin Wild · December 5th, 2005, 02:40 PM

I would guess it didn't gain up much outside, even if it was cloudy. Usually you can get away with a little gain up without introducing too much grain, but you definitely want to avoid it as much as possible.

Again, leave gain at 0 or -3 at all times, especially in a set up, film type of setting. There is no need to gain up. Add light if it's too dark. The gain feature and especially the auto-gain feature are really more tools for event videographers who don't have control over the lighting.

Ultimately, if what you shot looks good, then go with it. No need to ask about reshooting on these boards. You decide that with your eyes...throw out the technical stuff.

KW

Kevin Wild · December 5th, 2005, 02:41 PM

Joseph, to be honest, I've never really felt much of a difference between the -3 and the 0 gain. Any one else have a different opinion?

You should be fine at 0, but it certainly wouldn't hurt anything if you switched it to -3.

KW

Ash Greyson · December 5th, 2005, 03:09 PM

To combat grain you can turn down the sharpness, in this case you can do it in post when necessary. I have been in many situations where there was little or no light available and had to use the gain CRANKED all the way up just to get an image. Problem is that there is no real color info so I generally, if possible shoot in B&W.... check out some XL1s grabs, all with some gain, some with +30dB... I used the grain to help create a look, but it was out of necessity.

ash =o)

http://members.aol.com/ashvid/Grabs/

Kevin Wild · December 5th, 2005, 03:11 PM

Good point, Ash. You can also push the blacks down, as this is usually where a lot of grain shows up.

KW

Daniel Black · December 5th, 2005, 04:50 PM

What do you mean by "throw out the technical stuff" Thanks for all the other straight forward advice. I'm happy with what we have so far, although things can always be better and have desided to return during pick ups to get exactly what I need.

ash- regarding changing the sharpness in post production, is this easily acomplished in FCP and does it help much? I'm looking forward to editing and thanks for the cool stills, looked like a neat project.

Thanks to all!

Kevin Wild · December 5th, 2005, 05:43 PM

I'm just saying, it's a little silly to ask us "should I reshoot?" You need to look at your own footage and decide if it's grainy enough that you should reshoot. I wouldn't worry about anything technical AFTER the fact...if it looks good, it looks good. Just learn for next time...which is what you are doing.

Good luck!

Kevin

Greg Boston · December 5th, 2005, 06:07 PM

Kevin you are absolutely correct that gain settings of -3 or 0 produce the cleanest video. But the XL-2 being a newer design is actually quite good at running as high as 6db without introducing too much noise. But even then, you can go into the custom presets and set the noise reduction up a notch or so and come out pretty good.

The final shot in the night footage of Vienna that I saw just as the XL-2 was released last year was actually at 18db and it was almost noise free. But I don't ever set the gain to auto.

-gb-

Ash Greyson · December 6th, 2005, 01:56 AM

You can add a teenie bit of blur in FCP if you are finding the noise bothersome... as mentioned crushing the blacks also helps...

ash =o)

December 5th, 2005, 01:31 PM	#1
Daniel Black New Boot Join Date: Dec 2005 Posts: 10	Auto Gain on 16:9/24 I have been reading many of the threads on this forum and am learing a great deal that is not in the manual so thanks to all. What I have noticed is that most folks are recomending right out the box you should set the gain at or below 0 and not on auto. Unfortunately we have almost finished our principle... and everything we shot was on auto. I never really noticed noise exept when we were really in a dark big room. We came back to shoot the next weekend with loads of lights and this helped tremendously. We shot outside and inside an left it on Auto. Interviews and action shot both in and out. We are going for a "movie" look and so we shot everything in 16:9 at 24 frames. We did white balance checks everywhere and moved lighting around until we liked what we saw, but once again we never adjusted the gain. I have heard others report on noise, is this generally a "grainy" look? I have not really noticed but perhaps our footage could be better, perhaps we are not seeing the best. Can I get some comments on this matter and in the meantime I will play with these settings at 16:9/24 and see what is different at say gain on 0 to -3. Thanks to All

December 5th, 2005, 01:39 PM	#2
Kevin Wild Major Player Join Date: Dec 2004 Location: Raleigh, NC Posts: 540	There's not much we can say at this point, because we have no way of knowing how everything was lit. If it was all well lit and lit brightly, you'd probably be fine with "auto gain" on. However, don't do it in the future. Gain is DEFINITELY one easily controlled aspect of the camera that you don't want to use unless you absolutely need to. MUCH, MUCH better to light more and keep the gain down. I once used the auto gain when I first got the XL2 in a concert environment. Even with an on camera light, the footage turned out HORRIBLE. I was calling that button the "auto grain" setting. For the record, the grain that auto-gain gives you is NOTHING like the film grain you might be going for. Do not confuse the two. Video grain is downright awful and ugly. Put your gain on 0 or -3 and leave it there forever! KW

December 5th, 2005, 02:34 PM	#3
Daniel Black New Boot Join Date: Dec 2005 Posts: 10	Thanks Kevin. We did light pretty well and thus I think this is why it looks OK. Nevertheless we shot outside on a very cloudy day once and I bet it would have really helped. When we blow this up to big screen is it going to be more noticable? The main problem is we have no real way of getting our subject back to re-shoot. Also, when you set it on auto gain does it alway selected the higher setting. In theory it should put it below 0 if the light is low, isn't that the whole purpose of auto, to give you the best setting automatically? If we are planning to distribute this will these have to be re-shot? As I said before it looks good, but I can't help but wonder... We shot a good bit outside on sunny days too, do you set the gain low then as well?

December 5th, 2005, 02:38 PM	#4
Joseph Andolina Regular Crew Join Date: Mar 2004 Location: Everett, WA Posts: 178	I have a question. Is it better to just stick with the gain at 0 as upposed to -3 in all lighting situations? I just got done shooting a 5 min. short staying at 0. There were certain scenes (a bar scene) in lower ligthing. But since I wasn't able to use a high-end field monitor, I didn't want to take a chance and change the gain to -3.

December 5th, 2005, 02:40 PM	#5
Kevin Wild Major Player Join Date: Dec 2004 Location: Raleigh, NC Posts: 540	I would guess it didn't gain up much outside, even if it was cloudy. Usually you can get away with a little gain up without introducing too much grain, but you definitely want to avoid it as much as possible. Again, leave gain at 0 or -3 at all times, especially in a set up, film type of setting. There is no need to gain up. Add light if it's too dark. The gain feature and especially the auto-gain feature are really more tools for event videographers who don't have control over the lighting. Ultimately, if what you shot looks good, then go with it. No need to ask about reshooting on these boards. You decide that with your eyes...throw out the technical stuff. KW

December 5th, 2005, 02:41 PM	#6
Kevin Wild Major Player Join Date: Dec 2004 Location: Raleigh, NC Posts: 540	Joseph, to be honest, I've never really felt much of a difference between the -3 and the 0 gain. Any one else have a different opinion? You should be fine at 0, but it certainly wouldn't hurt anything if you switched it to -3. KW

December 5th, 2005, 03:09 PM	#7
Ash Greyson Trustee Join Date: May 2003 Location: Tulsa, OK Posts: 1,689	To combat grain you can turn down the sharpness, in this case you can do it in post when necessary. I have been in many situations where there was little or no light available and had to use the gain CRANKED all the way up just to get an image. Problem is that there is no real color info so I generally, if possible shoot in B&W.... check out some XL1s grabs, all with some gain, some with +30dB... I used the grain to help create a look, but it was out of necessity. ash =o) http://members.aol.com/ashvid/Grabs/

December 5th, 2005, 03:11 PM	#8
Kevin Wild Major Player Join Date: Dec 2004 Location: Raleigh, NC Posts: 540	Good point, Ash. You can also push the blacks down, as this is usually where a lot of grain shows up. KW

December 5th, 2005, 04:50 PM	#9
Daniel Black New Boot Join Date: Dec 2005 Posts: 10	What do you mean by "throw out the technical stuff" Thanks for all the other straight forward advice. I'm happy with what we have so far, although things can always be better and have desided to return during pick ups to get exactly what I need. ash- regarding changing the sharpness in post production, is this easily acomplished in FCP and does it help much? I'm looking forward to editing and thanks for the cool stills, looked like a neat project. Thanks to all!

December 5th, 2005, 05:43 PM	#10
Kevin Wild Major Player Join Date: Dec 2004 Location: Raleigh, NC Posts: 540	I'm just saying, it's a little silly to ask us "should I reshoot?" You need to look at your own footage and decide if it's grainy enough that you should reshoot. I wouldn't worry about anything technical AFTER the fact...if it looks good, it looks good. Just learn for next time...which is what you are doing. Good luck! Kevin

December 5th, 2005, 06:07 PM	#11
Greg Boston Wrangler Join Date: Oct 2003 Location: DFW area, TX Posts: 6,117 Images: 1	Kevin you are absolutely correct that gain settings of -3 or 0 produce the cleanest video. But the XL-2 being a newer design is actually quite good at running as high as 6db without introducing too much noise. But even then, you can go into the custom presets and set the noise reduction up a notch or so and come out pretty good. The final shot in the night footage of Vienna that I saw just as the XL-2 was released last year was actually at 18db and it was almost noise free. But I don't ever set the gain to auto. -gb-

December 6th, 2005, 01:56 AM	#12
Ash Greyson Trustee Join Date: May 2003 Location: Tulsa, OK Posts: 1,689	You can add a teenie bit of blur in FCP if you are finding the noise bothersome... as mentioned crushing the blacks also helps... ash =o)