Originally posted by MrApollinax Here is one on ebay:
battery grip for Pentax K100D Samsung GX100 - eBay (item 140240693347 end time Jun-18-08 15:43:15 PDT)
No vertical shutter release though. It seems all the nicer looking grips are battery only and the ones with shutter release have external cables. The one here though looks to have a built in Li-Ion battery which they state is good for 2000 shots. While it would help with the overall weight of the camera mechanically it looks like the battery door slides into a slot and remains open. I can't help but think that if something goes wrong you would snap the battery door cover off by accident. If someone else wants to give a go let us know!
I bought this battery grip(marked Travor P100) and received it a week or so ago. I was pleasantly surprised with it. It addresses one of the two things I would change about the K100D I have, namely battery life.
I charged the grip's internal battery the night it was delivered, and I've been using it off and on since then, without a recharge and the camera still reports a full battery. In fact I used it last night at a church concert, where I usually will need to change batteries partway through with no problems.
It appears to be significantly inspired by (if not identical to) the Ansmann P100.
Pros:
-I experienced a significant increase in battery life
-Doesn't need to be removed from the camera for recharging
-Light weight
-Comes with ac adapter for mains charging and a car adapter as well
Cons:
-Increases the size of the K100D considerably(I suppose this might be a pro for some users)
-Fiddly to attach(although I don't expect this will need to be done often)
Other:
-Vertical/Portrait shutter release(not important to me)
-Li-Po Battery is sealed in the grip, no way to change it without disassembly
-The cosmetics are close but not identical to the K100D body cosmetics(not important to me)