Canon Battery grip

Advantages Improves camera handling with larger lenses.
Disadvantages Doesn't "lock" in perfectly.

...The Canon BG E2 is the battery grip for the Canon EOS 20D. It also goes under the name of a vertical grip as not only does it provide a holding space for two batteries (BP-511A, or 6 AA's using the AA adapter it comes with) but it also provides an additional shutter release button on the "top" of the camera as you hold it verticaly (providing of course you rotate the camera anti clockwise from the horizontal shooting position). Battery grips are a must have for any serious amateur photographer who uses their camera intensively. I say amateurs because your average professional will be using a camera body that effectively has a battery grip built in as one unit. The reason for this "need" of the grip is to improve camera handling and also to give the camera greater balance when using longer and heavier lenses. Once attached to your... Read review

Advantages extra battery capacity, extra shutter button, better grip
Disadvantages price

...I've recently bought this to compliment my D30 and am glad to say its a worthwile investment. once the grip is locked on to the camera you instantly gain a vertical grip and shutter button, perfect for portraiture. secondly you gain an extra battery space so your shooting capacity goes from 500 to 1000 shots per charge on average. One of the best features is that it makes the camera look more profesionaland gives more to grip which improves stability when using longer lenses or flash, I find the camera is more balanced with the grip fitted when I use my 70-200mm F2.8 lens. The Grip is also compatible with the D60 and the newer 10D so users of these cameras can also benefit from its features and I would certainly recomend... Read review

Advantages Long life, fast recharge, small size.
Disadvantages None.

...I recently bought my first digital SLR, a wonderful Canon from the EOS range, which uses these batteries. Since I started using it, I've been very impressed with the battery. I have a 2GB memory card, that can hold nearly a thousand pictures, and the battery was never empty before the card was full! I use a mix of flash and none flash but even taking lot's of low light pictures barely dented this fantastic battery. I've since bought the Canon battery grip and a second of these batteries (as the grip holds two) and charging is now a very infrequent chore. The charge time itself is very impressive. From flat, it charges in about an hour and holds the charge like it's the first time you've used it. If you are keeping one battery charged and another as a spare (if you don't have the battery grip for instance) then you benefit... Read review