Canon 400mm 5.6 Arca Swiss Plate

I'm looking at purchasing an additional AS plate to just keep on the lens ring and saw some on eBay a 2" or 4" direct from Kirk Enterprises.

Does the size of the plate matter?

On that lens, probably not. On a larger, heavier lens that you would use on a gimbal head, the longer plate would allow you to slide the lens back and forth to balance the gimbal.

I would suggest to measure the bottom of the ring and get that's the same or just barely longer. The whole idea with the lens ring is that they design it to have the screw hole at the approximate center of gravity to balance it anyway. It's obviously not the exact center though, it's going to vary depending on whether or not you have a flash, how heavy of a body, etc. So a little extra length would give you that adjustment.

As mentioned above though, I don't think the exact balance would really matter unless you were on a gimbal or had a much heavier lens.

It's really nice to have the adjust-ability for balance. Different bodies weigh differently.

windpig wrote in post #13363632
It's really nice to have the adjust-ability for balance. Different bodies weigh differently.

+1

I shoot the 400 5.6 from a ball head and a sidekick when I need to. I have 3.5-4" plate on it. My 7d is heavier then my 40D and I have set it back a bit further for balance. I may not use the set up for panning but in wildlife, I use it a lot for steadyness in lower light situations and having the rig well balanced, makes it much easier getting on target, and being able hit the shutter quicker. Not for everyone, I understand but a little bit of extra plate can not hurt you. A short plate can cause you to wish for a longer one.

res wrote in post #13368242
+1

I shoot the 400 5.6 from a ball head and a sidekick when I need to. I have 3.5-4" plate on it. My 7d is heavier then my 40D and I have set it back a bit further for balance. I may not use the set up for panning but in wildlife, I use it a lot for steadyness in lower light situations and having the rig well balanced, makes it much easier getting on target, and being able hit the shutter quicker. Not for everyone, I understand but a little bit of extra plate can not hurt you. A short plate can cause you to wish for a longer one.

I purchased the plate on eBay for $17 via Kirk Enterprises on Monday and received today/Thursday. The plate fits nice and snug and will definitely get the job done but....if I had to do it again the 4" plate for $25 would have been probably a better option.

Either way look forward to taking out the kit for a shoot this weekend!