I recently purchased a 70-200 f2.8 IS II and have the following question;
Every once in awhile when I first turn on the camera and press half way down on the shutter button to focus and start up the IS, not only do I hear the faint sound of the IS kicking in, but I also see a very slight lurch of the entire frame in the viewfinder. It is very slight but definitely noticeable. While I understand that the IS is just kicking in, what I do not understand is what this lurch is about and why it only happens on very few occasions, again usually when I use the lens for the first time during the day.
I have read conflicting opinions in forums around the internet where some say this is normal, others say it is a sign that something is wrong. I do not see this lurching behavior with any of my other IS lenses but I DO see it every single time I use my Canon IS binoculars. Again it only happens very rarely with the 70-200 but when it does happen I wonder about it.