AGC - audio or video?

[Dark]

Hi there

This may be obvious to most but I've always thought that AGC regarded audio gain on cameras and not the video. I've just bought a Canon HF G25 and inside there are options to tweak the AGC:

https://www.canon.co.uk/Support/System/Search.aspx?TcmUri=tcm:14-1028149

It refers to video, low-light adjustment not audio. Why is this?

Sorry if this is quite a rookie question. It's got me puzzled!

Thanks

 

[Alex H.]

In film, if you need to work with less light, you choose a higher ISO/ASA (aka "higher speed") film. In terms of video, since you cannot swap the sensor out, the incoming signal must be adjusted in order to compensate for ensure outside of aperture and shutter speed. With DSLR cameras, they still call it ISO but it's really either raising or lowering the signal level from the sensor. With traditional video cameras, especially in lower-light scenarios, exposure is adjusted using gain, or an amplification of the incoming signal. What you're looking at is part of autoexposure controls on the camera. I'd disable that feature if possible and keep everything in manual control.

AGC can also, and often does, refer to audio.