i'm suggesting that a non-professional, without significant experience of manual focus going on a first safari will come back with very few good images and suffer considerable frustration
Well, you said many things other than that, but regarding this position in particular, my answer is "possibly."
While I do understand your point, in the end it really depends on the subject. For my own photography in the field, many times the quick AF means the difference between getting the shot and not getting it, and so I do see the same thinking you're applying here on the subject of a safari. That said, much of the time I still prefer to use MF over AF, once I have a cooperative subject, so if I didn't have AF I would still come back with many very nice shots. In fact, I would say the greatest sense of "frustration" I have usually involves AF
not picking-up what I want it to, when I use it, rather than my inability to get a clear shot when I don't and opt for MF instead. The truth is, sometimes an errant AF can blow a shot every bit as much as poor MF.
Still, if this was your main point, that an AF feature can help nail fleeting-opportunity shots, I can understand this completely. I think we could have dispensed with all the "confusion" talk and just discussed the advantages of AF vs MF in a safari, as every bit of this is relevant to the topic and should never have caused any confusion at all.
are you making recommendations from personal experience?
Do I have personal experiences in Africa? No. With either lens? No.
But I don't need experience with any of this to have recommended a thread showing a fellow boardmember an adapter that would enable him to affix a very nice Nikon lens at the end of his Canon. All of the "personal experience" in shooting in Africa won't change the fact that this would be a more sensible alternative than selling a whole set of gear and buying a new one, over just one lens.
In closing, I understand your point, but I don't necessarily agree with it. With an excellent lens, and with good light, I don't think MF is a very tough thing for even an amateur to do. My own view is if I were going to spend thousands of dollars going to Africa, for a once-in-a-lifetime experience, I would bring the best lenses and camera/s that I could possibly afford. And even on my lenses that did have AF, I would probably be trying to get most of my "keeper" shots with MF.
Jack
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