For many years my primary long lens for my wildlife photography was the Canon EF600mm F4L IS. It served me well and overall was an excellent lens. In 2010 I was able to borrow the new (at that time) Canon EF800mm F5.6L IS for the month long Images for Conservation Pro Tour Contest in the Borderlands of Texas. I quickly fell in love with it. It was much lighter and faster focusing than my 600mm with even better image quality and I decided to acquire an 800mm as soon as possible. I’ve been very happy with the 800mm over the last few years. Canon then recently introduced an upgrade to the 600mm F4 IS with improved AF, image stabilization, optics, and they dramatically reduced the weight of the lens making it significantly lighter than my 800mm. It ‘s getting rave reviews and I’ve seen some photographers state the new 600mm with a 1.4x converter is superior to the 800mm without a teleconveter. I was somewhat skeptical of that observation. On my recent “Winter Yellowstone” Photo tour one of my clients had the new Canon EF600mm F4L mkII with him and he graciously allowed me to try it out.
One morning during the tour we found this moose, a good ways off the road, feeding on some willows. I was able to compare my 800mm F5.6L IS without converter to the new 600mm mkII with a Canon 1.4x Mk III. I used my Canon Eos 1D mk4 camera on each lens. The image above was taken with the 800mm. Below I will show 100% crops from the straight 800mm and the 600mm + 1.4x converter giving similar focal lengths of 840mm vs. 800mm. All images were taken @ F5.6
This image is the from the straight Canon EF800mm F5.6L IS, no teleconverter
This image is from the EF600mm F4 L IS mkII + EF1.4x mk III teleconverter = 840mm.
I took 4 shots which each lens to make sure I had a good sharp example of what each lens was capable of. I focused in live view both manually and using contrast detection focusing, which is reputed to be very accurate. In this quick and dirty test, under typical field conditions I encounter during my photography, the bare 800mm was somewhat better optically than the 600mm with the 1.4x teleconverter. For my wildlife photography in which I often photograph bears and wolves at a good distance, the 800m is a better choice. I was impressed with the AF responsiveness of the new 600mm with the 1.4x. I wouldn’t say the AF was better than the bare 800mm but it was much better than I recall having with the old 600mm and 1.4x converter. At this point I think I will stay with my 800mm. I sure wouldn’t take any financial loss to make a switch. Also having the EF500mm F4L IS in my bag it makes more sense for me to keep both a 500mm and 800mm. I will likely upgrade to the new 500mm lens which is even lighter and will really compliment my 800mm.