Nikon doesn’t provide ‘official’ battery grip accesories for D3100 . In fact , Nikon never provide one for their entry-level DSLRs. Sad , but fortunately there are third-party vendors that manufacture battery grip for these cameras. One of them is Phottix , a Hongkong-based photography specialist. Phottix has manufactured the BP-D60 , battery grip for D40/D40X/D60 and surprisingly also works for D3000 (proof).
and now , they’re producing the BP-D3100 : battery grip for Nikon D3100. It’s directly from their representative ( link )
We’re currently expecting Phottix Battery grip for Nikon D3100 (BP-D3100) and Canon EOS 60D (BP-60D) by the end of this year!
Why use battery grip?
Battery grip is a special accesory for your camera which allows to hold several batteries at once. This will greatly extended battery life of the camera between re-charges . Another use for battery grip is for vertical shooting. It has extra shutter release button and control dial , placed in a position that comfortable to shoot vertical ( eg: for portrait shooting ). It also add bulks to the camera , makes the camera easier to hold for some people.
Phottix is holding the development , no ETA :( . Their reason is that “ they’re still monitoring the demand” . So , if you really want one .. visit this link and let them know !
Oh oh wait… some Flickr users emailed Phottix and got response that it will release this late February ! lets hope so ..
Update 18 March 2011