focus/stability problems

[carsfan]

I have a Canon HF M41, which has given me a lot of really nice footage. I've shot a few concerts that have turned well but most of what I shoot is my boys' high school band stuff. Right now they're in drumline and they have a very nice show called "Urban". Their first show in Tustin was not a problem, but they added a cool bass part for the next two shows and this is when the problem began. If you watch their Mission Vista show

you 'll see what I mean. During the powerful low frequency parts the video goes crazy, and the worst part begins at 4:25. BTW, I have a fairly heavy duty tri-pod and for this shot I also held the camera down firmly for just a slight improvement over the previous recording. I shoot in the sport mode with auto focus. I really need to figure this out soon since I only have a few more opportunities and I'd really like to get a perfect shoot. Any advice would be much appreciated.

[shoestringconcerts]

The Heavy Bass is shaking the internal stabilization elements in the camera,  not much you can do about it except try a different camera or move farther away which doesnt look like an option. 

Since you basically just shoot a super wide angle shot you might try placing it on a pillow or something similar to try and dampen the vibration  but i dont think that will entirely fix the issue.

[beatkilla]

I feel your pain because when i first moved from a Sony VX2100 which uses CCDs(global shutter) to a camera which uses CMOS(rolling shutter) it was the first time i ever had this problem and that is because of the rolling shutter.

The only solution that works for me when using a tripod is to use memory foam(walmart)pillow cut into thirds and placed under the legs to absorb the vibrations.....this works best with a HEAVY tripod and a HEAVY camera and also adding a backpack withn even more weight hanging from tripod.I 've shot this way every time when i film with a tripod and i have no issues at all even in the most bass heavy situations.

You scenario is probably the worst situation as you are filming in a gymnasium which has no vibration absorbtion qualities(no rugs) and also your filming in the risers which the vibration travel into and i'm sure everyone is tapping there feet along to the drums in the risers as well.Even using my method youd have to move off the risers.....other then that also i use a monopod and place the monopod on top of your foot.....this method allows your body(foot)to absorb the vibrations before hitting the monopod,or shoot handheld.In all situations other than handheld you should turn OFF the image stabilization as that will cause artifacts and should be used handheld only.

Your camera is pretty light so i would say the monopod on top of foot is going to be your best plan.