Avoiding noise

[Joe Batt]

I've come from a video background and had NO experience at all with DSLR's. I've been working with the FS700 now for about a week and it's really taken some time to figure it out. All of the work I do is controlled (short films, music videos, etc.) Nothings like weddings or sports events. The reason I mention background is because i've never worked with ISO before. Only gain, iris and shutter speed. All of my footage was coming out terribly noisy. The first thing I did was switch the gain to zero. That didn't work so I went in and set the gain to 0 and the ISO all the way down to 320. All of a sudden I was blown away at how great the picture looked! The only thing I'm still seeing is that in extremely low light, There is still a touch of noise just in the gradient coming out of total blackness to a lit subject. It's only noticeable when its a smooth transition, for example a single light against the edge of a wall that fades to black. So I have two questions:

1. Is it a sensible workflow to try to light every scene to look good with the camera gain and ISO at it's lowest possible setting and then bring it up when there's no other choice? (with my XL-H1 I never touched the gain, left it at -3)

2. Is there a gamma setting that beats all others in handling this particular issue?

Just to be clear I'm amazed with this cameras design and picture. Not criticizing it. I just want to make sure I'm getting the very best out of it.

[Colin Elves]

Originally Posted by Joe Batt

I've come from a video background and had NO experience at all with DSLR's. I've been working with the FS700 now for about a week and it's really taken some time to figure it out. All of the work I do is controlled (short films, music videos, etc.) Nothings like weddings or sports events. The reason I mention background is because i've never worked with ISO before. Only gain, iris and shutter speed. All of my footage was coming out terribly noisy. The first thing I did was switch the gain to zero. That didn't work so I went in and set the gain to 0 and the ISO all the way down to 320. All of a sudden I was blown away at how great the picture looked! The only thing I'm still seeing is that in extremely low light, There is still a touch of noise just in the gradient coming out of total blackness to a lit subject. It's only noticeable when its a smooth transition, for example a single light against the edge of a wall that fades to black. So I have two questions:

1. Is it a sensible workflow to try to light every scene to look good with the camera gain and ISO at it's lowest possible setting and then bring it up when there's no other choice? (with my XL-H1 I never touched the gain, left it at -3)

2. Is there a gamma setting that beats all others in handling this particular issue?

Just to be clear I'm amazed with this cameras design and picture. Not criticizing it. I just want to make sure I'm getting the very best out of it.

Hi Joe,

ISO and gain are the same thing, there's a setting under the camera menu (gain/ISO) setting that allows you to select whether or not it tells you the gain setting in terms of gain, or in terms of ISO. The confusion comes in because the ISO changes depending upon the gamma curve you use as it relates to the 'correct' placement of middle grey. If you more comfortable with gain, use the gain setting.

I will say, however, that with most gamma settings you can easily add +9db without increasing the noise in the image. So no, I wouldn't worry about noise unless it is so dark you need to go above +9.

I know what you mean about the odd noise in the shadow areas - I think that's as much to do with the combination of gamma curve and 8bit encoding. The gamma curves all push a large amount of DR (12-14 stops) into a very limited 8bit range of 256 values - it's not noise, it's the 420 8bit colour breaking down, combined with the AVCHD codec. Swapping to a more 'black friendly' gamma like Cinegamma 4 helps, but it won't be eliminated until you shoot 12bit RAW.

However, personally, outside of scenes with a lot of shadow detail, I find Cinegamma 4 too noisy.

You should also be aware that shooting high frame rates increase noise (and aliasing) significantly).

[Joe Batt]

Thank you, great info. I was talking about 24p, I should have mentioned that. Ill see what I come up with after reading this!