Quote Originally Posted by memostothefuture View Post
why the battery grip on the 5D MKIII? IMHO the batteries are quite good and with a spare or two I never had any problems making it through a day even when shooting thousands of frames and reviewing them.
I don't know about Vern, but as for me...

1) The battery grip balances out the camera. It fits in my hands better.
2) The vertical shutter/control buttons make shooting in portrait orientation much easier.
3) Instead of having to keep up with an extra battery in my pocket, why not already have it in-camera?

Those are reasons why I've had battery grips on every single DSLR I've owned. Once you get used to shooting with one, it's difficult to go without it.