Turn lens IS off when shooting at high frames per second?

[digiquisitive]

If I am shooting my EOS 7D2 at 10 fps in AI Servo, using (for example) Single Point Expansion and AF Case 6, with Tv at 1/1250th,  should I turn off the IS feature on my 300mm f/4L IS lens?  Why or why not? If the camera is tracking a subject and shooting at 10 fps, seems  to me the lens will have to adjust focus 10 times in each second of shooting.  Will this adjustment be hampered or helped by leaving IS turned on on the lens?  Will IS actually be adjusting right along with focus (as a part of focus)?  Does this have the potential to slow the burst rate down?  Potential for less-than-optimum sharpness shots?  Just for reference, I always shoot handheld, even (or especially!) under these conditions. I can find no advice or discussion on this topic, but it seems highly relevant.  Thanks to whoever would like to opine on this.

[digiquisitive]

Nice RC shot!  Thanks for sending.  Point of clarification, please: I assume you mean you use 65-point automatic selection in the full AUTO configuration (you do not use the single AF point implanted in the viewfinder with the other two non-AUTO options -- AF tab 4, item 6, choices one and two), which means the camera both chooses and tracks what it identifies as the subject. That's why you move to an Expansion AF Point mode when concerned about conflicting/confusing backgrounds, right?  You may find this of some interest: I shot some Canada geese yesterday when they were first in  the open sky, but then they flew across a background of fir trees, and wove in and out of a group of trees that were between me and them -- the tracking never wobbled, always kept them in focus irrespective of the changed background or intervening foreground (I have Tracking Sensitivity set at -2, which is "lock on and forget what else comes into the VF").  I was shooting with 4-point Expansion AF and AI Servo.  Thought you might find that of interest.  I can see the advantage of having all 65 AF points available for tracking, but am concerned about most of my subjects not being the sole or closest object to be automatically identified as the subject, then tracked -- that's just the kind of stuff I normally encounter when I go out.  I can see the advantage of 65-point auto in your RC shot. Thanks again.

[digiquisitive]

See my 3-24-2015 item on this topic. My 300mm still sometimes requires me to kick start it manually to get it into approximate focus before it wants to home in. Problem has been with me for 3.5 years -- at least. Was probably there with the old 7D, as well. Time for an upgrade, Canon.

[cicopo]

All points active works well for me since my targets can change direction quickly & are usually up against the empty sky. Some are also very fast so just keeping them in the viewfinder can be a challenge.  See my reply here.

https://community.usa.canon.com/t5/Lenses/28-300-Zoom/m-p/252379#M13908

[ebiggs1]

"...a new 300 L lens will be of some benefit to those of us with a lot of gray hair"

Don't forget those of us with little to no hair of any color!  The ef 300mm f4L is one of a very few lenses I consider a good candidate for using a tel-con. It handles it well.

[ebiggs1]

" It can go into sort of a feedback loop where the IS is actually causing image shake."

I don't know if this is happens or is even possible.  All I can say it has never happened to me.

[ebiggs1]

 I have a great number of Canon lenses. I don't have every lens' manual here in front of me. But the couple I do have at my computer desk say, "When you use a tripod, the Image Stabilizer should be turned off to save battery power."  That is all I can see.

If they sensed a tripod, there would be no need to manually turn IS off.

[digiquisitive]

Thanks for all of your help.  Old guys rule!

[digiquisitive]

Thanks, cicopo. Very nice work. And I liked the info at the link.