Before considering a purchase of this lens, it was highly recommended to obtain a rental or loaner. I joined the CPS program, paid the annual fee and requested the 600mm as a loaner. The time period was from its arrival on 11-22-13 to 12-3-13.
My intent was to man handle this lens without use of a tripod or monopod for the entire duration on a Canon 5D Mark III. This would include 1-4 hour segments most every day including hiking on dirt trails, paved trails and the like.
I found one key trick to this whole process and that was to use a 3/8" male threaded cone shaped handle that would screw into the lens foot. (see attached photo). Along with the lens strap and camera strap, this was going to be my sole means of trekking with this lens. (I'm a 54 year old male, about 175 lbs. and workout approx. 2x a week for the past 13 years). I've only offered this info for no other reason other than to help formulate what it might take "should you desire to carry this lens hand held" vs. using a tripod with Gimbal or monopod. Let's put it another way, weight and cardio training will be to your advantage. Some of us out there would not buy such a lens if it is going to require anymore than carrying a lens and camera body though I know many that wouldn't consider it any other way than have a tripod/monpod and gimbal. A close friend of mine carries around a 1D IV and a 500mm on a Gitzo tripod with a high end gimbal head. I thought that was far too cumbersome for my personal taste so opted to hand hold the entire time. Again, that's just me and just trying to offer some confidence for those of you used to carrying around a 100-400 or a 400mm prime..this is solely the point here and potentially do able but testing this scenario first is recommended.
If you've not seen the lens in person, it extends with the lens hood about 28" with camera body total was close to 31".
Overall, I had excellent success (about 95% wild birding shots). I found that by using F4 was a disadvantage as when focusing on the birds eye especially at close range the DOF is wafer thin. So shooting at 1/1000 or higher in Tv mode and letting the camera select the Av was not a good choice. I reverted to Manual, F8 most of the time with a shutter of 1/1000 or higher and saw a significant improvement on my birding photos. If you are not familiar with the DOF calculator online, this would be wise to look into especially in using this type of lens.
In using the 5D Mark III my choices outside of the shutter and aperture were of course AI Servo, Case 2 tracking, Faithful, Evaluative and Auto ISO. On the lens itself, I was mostly on Mode 1 (sometimes Mode 2 when tracking birds in flight), IS was "on" (though I am aware of using IS beyond 1/640 shutter. I did try with IS off and noticed my hit rate went down quite a bit as to be expected.
I noticed "this lens" was quite slow "initially" finding a bird in flight. More specifically, a bird in flight against the skyline. I am unsure if this was my particular loaner or a possible camera choice. In either case, outside of this skyline issue, the focus was extremely fast and the drain on the battery was minimal. On average about 33% battery drain per day. I did encounter yesterday a lockup on the camera with a flashing "A" in my view finder. A simple reboot cleared this and I went on with my shoot. In calling Canon, they had not heard of this flashing "A" but are going to check the 5D this afternoon.
All in all, its quite impressive as you would imagine and if you have your eyes and wallet set on this, I would strongly recommend renting or acquiring a loaner first. Buying this sight unseen (for those that have never used a lens of this magnitude prior) may not be a wise choice as I wish to emphasize it's very cumbersome. For those of you coming off a NON IS version or Version 1 you'll notice a big improvement in weight distribution. its truly well balanced in that respect.
I hope this write up will help anyone out there considering the 600mm IS II lens. If you're interested in seeing some birding photos and similar with this lens my flickr account is: http://www.flickr.com/photos/revup67/with/11185308965/
. Thanks for reading.