Canon 300mm 2.8L IS mkII with the Canon 1.4x mkIII and 2x mk III teleconverters

I have the mark I I got recently.
With 1.4x and 2x it does very well without much impact to the IQ or AF performance.
The mark II does even better, so I wouldn't worry about it.

But, if you consider to constantly use an extender, its time to get a longer lens.

If you are complaining about 1.4x III + 300 Mk2, you are most likely using it in the wrong camera. You should use 5d3 or 1dx. I used the 300 Mk2 with 2x III and results were superb.

Birdman7 wrote in post #16118869
The Canon 300mm 2.8L IS mkII is one the best single-lens iv used due to its performnce and versatility for bird photography as its extremely sharp, light and fast AF and performs suberbly with both extenders whilst maintaining AF and IS.

Its a no bainer and well worth the investment.

I'm thinking the same thing. If the 300 I & 1.4xII works well, then the 300 II & 1.4xIII must work better. At least it dang well better, considering the increase in cost.

Version II has better IS, is a little lighter, and according to TDP provides a sharper image with the 1.4xIII than the previous version.

I may buy the 300 II & 1.4xIII to hold me over till my 200-400 shows up, which could be a long time.