Sigma's SD1 introduced a new body, and thus, a need for new accessories to the SD system. The first of these dedicated accessories has arrived, the PG-31 power grip, which provides a vertical grip, capacity for two BP-21 batteries, and an additional shutter release. The PG-31 is now shipping, so we've equipped our SD1 Merrill with one.

One of the most appealing aspects of the SD1 is the compact design. Despite packing dual processors and a 46Mp sensor, it's one of the lightest, smallest professional bodies made, with a comfortable grip and well placed controls for normal horizontal use. Using it for portrait orientation photos has been a little less comfortable, as the shallow body provides little to hold onto.

Fitting the PG-31 is easy. Remove the battery cover from the SD1 by sliding the silver screw across to disengage the hinge, and it can be stored on the grip:

The twist lock is used to secure it, so even if you remove the grip for any reason, it won't fall out.

Once installed, two BP-21 batteries can be used.

A textured surface at the rear provides a secure thumb location.

Operation with the grip is straightforward. The additional shutter is not joined by additional control wheels, so it's necessary to make adjustments for exposure and so forth on the camera body; there's an on/off switch to disable the additiional shutter button. Battery life should allow for over 1,000 images with two fully charged, healthy batteries.