« on: July 17, 2014, 08:55:34 AM »
Whilst not South Africa I did go on a specialist photographers safari to the Masai Mara last September and going again this September. I had the same dilemma as you, in the end went with the 300f2.8mk11 on the 5dmk111. What a combination for early morning shots and late evenings f2.8 was the norm. Got some stunning Leopard/Cheetah shots at ISO 5000 with shutter speeds below 1/20 second. Those photographers who had the 200-400 and 500f4 were not able to get the shots required.
Of course these big lenses came into their own when photographing in better light. When this happened I added either the 1.4 or 2x extenders, both mk111 and they were just brilliant.
For me the 300f2.8 is the most versatile lens around. Do you really need to spend £10k for a lens that you have principally got covered. The other factor is weight the 200-400 is a hefty beast and takes some handholding whereas the 300f2.8mk11 is comparatively light.
I did take two bodies with me namely the 7d which was only used very occasionally. I also took a 70-200f2.8mk11 lens which was used for closer subjects. I had no problem with dust and was able to change lenses without any issues.
Hope this helps and have a great time.