I need to get an extra battery for my 1DmkIII and I was hoping someone would share their experiences with aftermarket batteries. Any brands to stay away from, any to gravitate towards? Should I suck it up and buy a genuine Canon battery?

Thanks in advance.

I am not aware of any aftermarket ones available for the 1DIII/1DSIII

i ordered one from bestbatt the first one i got had a bad cell in it, i contacted them, they got out a replacement that actually lasts longer than the OEM canon that came with the camera.

I had two in a row (the second a replacement for the first) from Bestbatt that didn't work. If I decide I really need a spare, I'll go with the genuine Canon one next time.

Phottix Titans are good aftermarket ones for the MKIII. I had two, and they lasted actually a bit longer than the OE, and the camera didn't have any issues at all with them.

I have this Pearstone battery
http://www.bhphotovideo.com/c/product/564334-REG/Pearstone_LP_E4_LP_E4_Lithium_Ion_Battery_Pack.html

The fitment is basically the same as OEM and everything works fine. i haven't had to use it yet, because the OEM honestly lasts so long, but I did charge it and put it into the camera to make sure everything worked... seemed fine. Communicated with both the camera and charger too.

Thanks for the quick responses everyone. I'm looking for a Phottix Titan and I can't find it on their website. Did they discontinue them or do they not make one for the 1DmkIII?

I picked up the Pearstone today.

Do any of the aftermarket batteries let the camera display the number of shots taken like the OEM one does? Are there any other differences?