I was talking with a fellow T2i owner over on my Facebook page and he was wondering how to shoot an indoor band in low light without grainy images. I thought it would be beneficial to share our conversation with all of you...
Dax's Question: I've got a band I'm shooting in low light. I use a high ISO and a fast shutter speed right? would you recommend an Aperture of f/1.8, and should I adjust my fstop according to the light in the room? I notice on my last shoot my photos were grainy. I was using ISO of 1600, shutter speed of 1/100 and Aperture of f/1.8. How can I solve the grainy problem?
Moose's Answer: I would just set the ISO to Auto to ensure you get an accurate exposure everytime. The T2i will automatically try to use the lowest available ISO whenever possible.
In regards to shutter speed...when shooting in Aperture priority, you control the aperture and the T2i controls the shutter speed. If you need to "freeze" fast action in low light, then switch over to Shutter priority (Tv on the mode dial) and start with a speed near 1/250. This is usually sufficient to stop most band movements. When you shoot with fast shutter speeds in low light, the camera will need more light in order to get an accurate exposure. You could try using an external speedlight, but they're really only effective in small rooms or if you're close to the subject.
If you can't turn up the amount of available light in the room, then the camera will be forced to make the image sensor more sensitive to light. In this case, it will use a higher ISO in order to get an accurate exposure. Higher ISO's unfortunately will produce image grain (noise) and sap some of the life (color and sharpness) from your photos. Noise Ninja is a fantastic piece of software that reduces overall image noise from your low light shots. You might give that a try: www.picturecode.com.