steepjay said:
I just had a lengthy conversation with a buddy of mine who was agonizing over 400/2.8 + TC vs 800/5.6, similar decision. The decision of reach without TC vs. the versatility of the faster, shorter, lighter lens plus TCs can be a challenge and is very personal. I used to have a 300/2.8, it's great for some things but I don't think it fits the bill for what you've described. 300 is too short for birding and safaris so you'd be living with a TC full time. I did a week in Tanzania with 300/4 a few years ago and had the 1.4 on a lot.
If you've already used the 500/4v1 you know the handling challenges associated with a lens this size so no point getting into that.
My vote, sell your 100-400 and get the 400/2.8. It's $1000 and a pound more than the 500/4 but you'll get 560/4 with a 1.4 and 800/5.6 if you get the 2x at some point.
I kind of have a similar question. Rather then start another very similar thread, while not trying to hijack this thread, I thought I would pose my question here, since interested parties are already engaged. If money is an object, but not a prohibitive issue, I wonder about the following lens choices...
Okay, so I have the 300 mm 2.8 II. I work about 1 million hours a week, so I rarely get to go anywhere. But, I have a nice lens collection because, well, I like photography and it's something I can do in brief moments between work. So, I see that like new 800 mm I asked lenses can be purchased used for about $10,000. There aren't that many reviews of the 800, but the couple that I read said the lens is "very sharp, but not tack-sharp". And, when you look at the digital picture website lens comparison, it appears to be a little bit better than the 300 mm plus 2X Tele converter, but not strikingly better. So, the question is, when shooting long shots, is the 800 mm that much better than the 300 mm 2.8+ 2X Tele converter? Whether it's pictures of the moon, or pictures of the refrigerator magnets taken from the other end of the house, will I see that much difference? Another words, if you have the 800 mm I asked lens, or even better, have the 300 mm 2.8 with Tele converter and the 800 mm, would you get the 800 mm again? I heard from a very knowledgeable source (the Canon price watch guy) that in the last few months, the big camera stores were liquidating their 800 mm, because with all the new big white lenses, they were afraid of getting stuck with them. What is the cheapest anybody has seen them go for in the last year? Is a used one that's like new for $10,000 a great price? Or, were the big camera shops selling them new for not much more than that? Thanks.