Concept: 2 out of 5
Execution: 2 out of 5
Yeah, but: It's a lateral move.
The Long Version: Camera hand straps are an odd thing. I looked at the Canon E1 strap three years ago, which requires a battery grip with an available strap lug to work. The Canon E2 is different in that it attaches to the tripod socket, so it will work on any camera with or without a battery grip attached. That's not without its own compromises, but at least it's a huge win for compatibility.
A grip strap distributes some of the cameras' weight across the back of the holder's right hand, and I do find a big difference in how tightly I need to squeeze the handgrip of the camera that it's attached to. It's not that holding a camera is an inherently difficult task – although hand strength and mobility can be a barrier to this hobby – but an easier grip leads to less fatigue and smoother action. In an entirely subjective opinion, I would say that having a grip strap improves my handheld slow-shutter photographs – technically, at least.
But there's no such thing as a free lunch, and the E2 certainly isn't cheap. In addition to the $60 MSRP, locking in your right hand can make it difficult to reach some of the camera controls; by attaching to the bottom of the camera it prevents the camera from sitting naturally on its base. It does have a second tripod socket built into it, but I'm still not sure that I would be happy daisy-chaining it to a tripod or one of those fashionable hip-slapper sling straps. The former is a matter of stability, in that adding extra height and another linkage detracts from it, and the latter is just a simple matter of good sense.
The Canon E2 Hand Strap – not to be confused with the Canon ST-E2 Speedlight Transmitter – is an excellent match for larger cameras that don't have vertical grips. The Canon 7D and 5D Mark Whichever, Nikon Dx00 series, and the occasional Fujifilm GA645 are all good candidates. Smaller cameras that don't have a grip tall enough to accomodate the entire hand won't benefit as much, while it will block the portrait grip on any camera so equipped. For those dual-orientation cameras with built-in strap lugs the Canon E1 remains the best option: it's just a pity that they've discontinued it.
last updated 10 feb 2012