> You've three options for an external battery holder. The MP-1 is the large battery holder with a vertical grip. This adds maybe 35 or 40mm to the overall height which may be too much for easy storage in your kit bag, furthermore many photographers dislike the added height when flipping the cammera to the vertical on a tripod, as it pushes the centre of gravity further away from the tripod's centre post. The advantantages of the MP-1 include a separate vertical shutter release, a wrist strap option, and the ability to switch between the lithium cell and the four AA size cells.
Second is the P-8 power pack, again taking four AA size cells (re-chargeable or otherwise, as you wish). It plugs into a socket on the base of the camera via a cable about 1.5 metres long. It weighs next to nothing, is relatively cheap and compact, and allows you to keep the power source next to your body in very cold weather. The down side is that you're tethered to the camera and because it plugs into the base you have to set the camera down on its side should you wish to rest it on the floor.
Thirdly I believe there's a new power pack, that I've never seen, which takes four C size cells for even more capacity. From what I can gather it's identical to the P-8 just bigger.
For many users the biggest advantage of a power pack is that the firmware recognises an external power source and no longer shuts the camera down after sixteen seconds, so you can shoot without a delay. This only applies when there's film in the camera so you won't notice the feature when evaluating a filmless body in a camera store.
Now here's the thing, a month or so ago I returned my 645 to the main Contax European service centre in Germany for an unrelated repair and now it no longer shuts down after sixteen seconds even if I'm NOT using an external power source. I've only just noticed this as I almost always use a P-8 or MP-1, and I wonder if there's been a firmware upgrade which is automatically applied at the service centre?
Can anyone shed any light on this? Has anyone had a similar experience or bought a brand new camera and noticed that it doesn't shut down after sixteen seconds?