I have noticed that agc adds alot of noise to the picture in low light and even in other circumstances and lighting situations so I am going to leave it turned off unless it's absolutely necessary. What do you guys think ?

I can't think of any reason to ever shoot with AGC on, unless maybe you're doing something like that "Cops" TV show where they follow cops around at night.

No Deal, Howie.

No deal. Personally I always set the cam to manual mode and map -3db, 6db and 12db to the gain toggle.

That was the very first thing I did...AGC off, -3db dialed in. I'm still learning the vagaries of NR1 and NR2. The A1 is noisy IMO out of the box, but it looks a ton better with the few tweaks as far as noise. If you're shooting auto mode (like following your tot around the house) AGC is your friend.

Does using negative gain have any side effects? good or bad?

anything AUTO is basically no deal as we are smarter than the computer chips and mathematical formula. One of the main difference between a consumer and prosumer cam is the ability to go fully manual.

Auto gain is handy in certain situation with live event but with A1, it is useless and a waste of a button because you can't limit your gain.

AGC is good if you hand your camera to your mom or a little kid. But if you need to adjust gain, it's easy enough to do it yourself. The camera constantly changing gain levels and adding noise to the picture looks really unprofessional.

Leave it off. Just my two cents.

Gain virtually always imparts noise into the image. Letting the camera do it is frequently imparts noise that you don't see until post.

In consumer cameras, it is necessary because the owners don't know how to adjust gain...or even what it is. On still cameras they label it as a film speed.

Auto exposure...sometimes. Auto gain...I never use it.