For sports, wildlife, you need all the help you can get. I used an EF 400 f5.6 L for a long time. For birds in flight, I use 1/4000 with auto iso with good results. With good light, you can get away with a slower shutter. The lens is relatively light weight. Recently I have gone to an antique 500 f4 not i.s. with great results. Merritt
Some time ago I sold my Canon Miii and 7d and purchased a Fuji xt1 with several of the best lenses. I had the outfit for several months. Very fine equipment and great iq. The Canons seem so easy to set up and operate after the Fuji. I missed the view finder. Some of the mirrorless have vf's.
Merritt
Download and install Classic Shell which converts 8.1 to Windows 7. Be sure and download from the main source to avoid having alot of junk installed on your computer. Classic Shell is free. Merritt
I have the original ef300 f2.8 and the f4. Both are marvelous lenses. The 2.8 weighs 4+ pounds more than the f4. Merritt, Dallas TX
I owned an XT1 for about one year along with the 23, 56, 55-200 and the Zeiss 12mm. I purchased the Fujis after selling my 5diii and some lenses because of the weight. The Fuji system takes great photos. My fingers are too large for the XT1. Also, I find the operating system very tedious and was never able to master it. Canons seem so easy to operate after the Fuji. I especially enjoy the full time manual override on the lenses. I was able to get about 55% of my money back on reselling. All were mint.
Did you format the card (s) in the camera? Merritt
Hello, you might consider a Fuji XT1. I sold my 5diii for the Fuji and am happy. Superb IQ. Merritt
Hello, that's one of the sharpest primes around. Don't hesitate to use 800 iso for still and 1200 in flight. I use 1/2000 with auto iso for in flight with reasonable success. Merritt
Hello, I recently sold my Canon 5D Miii for a Fuji XT1 with some primes and a Canon 7d Mii with a Canon EF 400 f5.6 prime. I really love the Fuji and the IQ is superb. The 7dmii is phenomenal. Merritt
Attached is a photo I took yesterday with new 7dmii. iso A, 1/2000, manual select:large zone AF
Merritt
Hello, have shot alot of early morning birds in flight. Best results have been shutter speed 1/2500, iso 800. Canon 5iii. Merritt
You might look into the Fuji XT1. Am in process of downsizing to this marvelous mirrorless camera from 5d miii with no regrets so far. Am keeping my EF 400 f5.6 for birds in motion. Will get new 7dmii if ever comes available. Merritt
Make sure your battery is good and then update the firmware. Similar problem with my 5Dmiii and that solved it. Merritt
Hello, you're stuck with f5.6 on that lens, use 1/2500, iso 800 spot focus
Hello, I have a Miii and agonized over the same decision.
I wound up with a Canon 14mm f2.8, the latest version used from Amazon. It is an awesome lens. Rent one and you will not want to give it up. There is an older version for about half the price which is also great. Merritt