I saw this on Amazon and thought I should mention it. "Battery Grips" are detachable extensions which fit on the bottom of your Canon 5D, 20D, 30D, 40D and allows for a few things:
1. To hold the camera vertically without strain on your wrist, the grip allows for this by including a second shutter button.
2. It allows for a second battery which means more shoot time without needing to change lenses. Good for image stabilized lenses as they draw power from the batteries. (But lets be honest how hard is it to change a battery? lol)
3. Greatly adds to WOW factor. The camera looks bigger, and believe it or not, clients are more impressed with the bigger hardware.
I am very careful about recommending off brand gear. What it comes down to for me is a balance between Functionality first and foremost and secondly price. If it works as good or better than brand name, and its significantly cheaper- YES.
This grip costs $80 new, compared to nearly $200 for the Canon version. Also, it comes with 2 batteries, AND if you look very closely, you will see that there are 2 additional shutter buttons, one for you lefties. There have been times I have said to myself....I wish I had a button on the other side (just due to the composition at hand.)
While I dont have an immediate need for it now, this will be the next grip I get. If anyone else gets it and tests it out, please let me know what you think.
Opteka Battery Grip