Talking the 200-400 again

So far I'm not convince 200-400 has similar IQ as prime 300 or 400; saw few shoots from POTN sample thread, one of the guy keep using f/8 or plus for the Safari shoots, which I believe you CAN do it with your 100-400 with similar IQ @ f/8, too. Also after seeing the physical size of 400 prime and 200-400, I'm going for the much lighter 300 prime this time.

If I am going to spend $12K, I will go for the 600 prime for sure.

mbridger68 in Flickr post some his Safari shoots past 6 months, his shoots are technically and IQ perfect, and look like from 300 and 500 prime; your shoots are perfect timing and have those action feeling. It will be physically challenge to use 200-400 for Safari action, I think.

Good luck and I'm looking forward to see more shoots from you regardless whatever lens you're going to use

Few things to consider.......I have the 200-400 + 1DX, I just sold my 400 2.8 II, I don't really use my 1.4/2x any more....... If you are a wildlife shooter, the zoom/single package is worth the money. It means you can be flexible in your crop vs distance from lens. There are no panics to get a TC 1.4/2 in or out of the setup and MOST importantly, when shooting in outdoor weather with something like a lenscoat on it, you don't have to expose the most sensitive parts of your treasured kit to the elements/or miss the shot either...... I'm talking about precipitation/dust/san​d/humidity/extreme heat/cold. If you are going mobile to get to your subject, this lens is going to reduce the amount of kit required vs massive focal length. I Take 200-400+70-200+16-35+1DX. You can cover everything outdoors with that lot.

As far as shooting things like sports, you are going to have the benefits as above but you will miss the F2.8. If you shoot airshows as I do, this lens really is apex. Something to consider about using extenders externally with this lens: I used to shoot a lot at 800mm (400 2.8 + 2x) at F4. With this lens you don't have that option. Nor will you keep all your AF points. But shooting things like formation aero's, this lens IS the best.

So, I say if keeping all your AF points+wanting to use more than 560mm with this lens. Stick with a prime setup. If you want flexibility at F4-5.6+200mm-560mm in one package, buy this lens.

As far as sharpness, IS and focussing go: nothing less than as good to better than the Mk II prime telephoto's.

An aside, the drop in CPL (proportionally insanely expensive) is worth doing!

Good luck saving for this lens!

777guru