I've been reading a lot at Strobist. And, boy, I must say I'm still confused, but the light is starting to glow. I also recently got Scott Kelby's third Digital Photography Book which deals a lot with flashes and deals with off-camera flash (which is what Strobist is all about).
Anyhow, my ring light fits on my macro lens and you can take it off and hold it via it's cord, if you like (you could bungee it to something, but the cord isn't very long). I was playing with it today. The whole idea with flash, as Scott Kelby says so plainly, is to use it in manual mode and balance your flash with the ambient light. There are a couple big problems with that idea though - 1) if your flash is sitting right next to your lens the light is non-dimensional and hard, 2) you have to shoot in manual mode on both your camera and flash to really shoot manually and it can be tricky to get the hang of, and 3) the ambient light (existing light), especially if shot indoors, is usually a different color than the light from the flash.
So, ultimately I'd like to get off-camera. That will involve some purchases. I think I am sold on not going the Canon route for getting off-camera because, although it is my cheapest up front possibility, it is the least flexible. Either buying a second Canon flash and using it as master, or buying the Canon wireless controller, limits your range to a 20-30 degree line of sight. I might want a second Canon flash down the road, anyhow, so that might be a possibility of a next purchase, but I'm not sure. What I've got my heart set on are a pair of Pocket Wizards. These are really fun toys if you don't know what they are. They can remotely trigger your flash or a second camera for that matter. What fun! One day.
So, I was playing around with my macro ring light today and toning down its power and holding it off to the side (my beginning attempts at off-camera flash).
Money set aside at this time may not cover the pocket wizards and accessories at this time, however, what I want to talk about next is that color cast your pictures can get when shot with flash. You can alter your flash light to match the ambient light by putting on either an orange gel (most lighting) or a green gel (flourescent lighting). Gels are cheap and can be velcroed or even taped on.
The following picture is an example. The area, after the fade off from the flash has a real yellow cast. The wall was not yellow. If I am to alter my entire photo, it would be very off-cast. But, I learned a cool little trick in Photoshop recently.
How To Photoshop Out A Color Cast
What I did to this photo and what you can do with most photos (but not all) is Select a Hue/Saturation Adjustment layer and choose the color which is dominating your photo. Then desaturate your color to your liking and increase your lightness. In the case, I desaturated 50% and increased lightness to 100%.
Here is the original: