Canon EF 70-200mm f/2.8 L (IS) USM / Discuss

Prontopac says:

I've noted on several occasions that after using my 70-200 lens for an extended period of time it gets, for lack of a better word, "tired."

It becomes sluggish while focusing, zooming in and out hunting for a focus point, and will fire non-focused resulting in a blurry photo.

Everything else in the photo shoot remains the same, subject, lighting, distance, but the auto focus begins to fail after a couple of hours.

Battery issues? Lens motor heating up?

Any ideas?
Posted at 1:30PM, 19 February 2012 PDT (permalink)