Neuro, it's amazing how the memory fades with time. It's fifteen years since I stood on the edge of the Ngorongoro crater and I had forgotten it had a lake in it! I didn't mean to imply that you would be able to make out the individual creatures, just that it would look less sterile than my more recent visit to a caldera elsewhere. Maybe 24mm will be wide enough after all.

I recall another safari thread a couple of years ago here. Unfortunately, some of the posts were truncated when this site was moved to a new host, but plenty of useful tips remain.