Have you used any RF extension tubes ? Were any worth recommending?
Do any of them preserve autofocus capabilities?
I've got a set of Meike and a set of JJC ones. They're the same tubes, just different brandings. The Meikes were the first to market so I bought them first; one of them mounted a little bit loose so when the JJC-branded version came out a fraction cheaper, I bought that set and they've been totally fine. If JJC hadn't put out their one cheaper I'd have happily just bought another Meike set. I've had enough tubes for all mounts you can name, going back to the 1960s Canon R & FL mount up through every decade since, Fuji, Sony, Nikon, you name it, and the looseness I found in the first Meike set is totally typical of common copy variation. I don't believe either brand actually has a better or worse chance of being loose than the other, it's just luck.
Yes, they keep autofocus, and all other electronic operation. I've not seen an extension tube made in the last twenty years which doesn't retain autofocus, other than ones made for lenses made pre-autofocus, of course.
I own the RF 100-500mm, the RF 800mm f/11 and the RF 1.4x and 2x, and have posted a comparative thread
https://www.canonrumors.com/forum/t...-100-500mm-rf-800mm-and-ef-400mm-do-ii.40550/
I found on the R5 the 100-500mm + RF 2x at 1000mm, f/14 outresolves the bare RF 800mm f/11, and I had to put the 1.4x on the 800mm to give 1120mm f/16 for it catch up. The TCs might not be as good on the new 100-400 f/8, but we don't know yet other than diffraction will be worse. On the 100-500, they are incredibly good.
Fair enough then, but given my experience with the 100-500 on TCs being weaker than the 800 f11, I'm going to put this down to copy variation and say you can't gurantee results. It could be that you got an unusually good 100-500 or TC, or an unusually poor 800, or I hand my hands on an unusually good 800 or an unusually bad 100-500. Unless someone can test a sample group of at least ten copies of both lenses and TCs, we can't chalk this up as any kind of consistent trend.
The latest figures I could get on them were from 2017, where they had total sales of about 500 million USD. Canon's Imaging division that same year had annual sales of about 10 *billion* USD- about twenty times as much.
This is an erroneous point because Canon's 'imaging division' includes much more than just the consumer photographic products. That US$10b includes printers, scanners, medical tools, security cameras, military tools, binoculars, scopes, industrial sensors and processors that they sell to other companies, and even paper.
Right now, according to Canon's 2020 financials, the imaging division has taken a hit of more than 90%, with the overall company losing a bit over US$80m last year and the imaging division in total only generated around US$28m in operating profit.
Now, e
very company had a weak 2020 due to covid and the semiconductor shortage totally destroying most industrial sales, so I don't expect Tamron made much more than that either (I haven't looked at Tamron's latest financial reports), but the fact remains that Canon absolutely are not currently raking in US$10b, the consumer products we're talking about here never got them to that figure in the first place, and no matter which way you slice it, Tamron's lenses are and have been the best-selling lenses in the world for the last couple of years by a big margin, and not only does it mean Tamron's lenses have shifted units but it also demonstrates the market share that Sony now has.
Basically, if you're going to bring up the financials, you really need to learn what they really mean and you need to stick to the most recent ones. Every major manufacturer publishes their financial reports publicly and they're usually just a short Google away. Everything you wrote is basically meaningless and inaccurate because you didn't check what "imaging division" means in Canon speak.
Thank you very much for your extremely thorough response and feedback about your experience with the EF 400mm 5.6L! Your reply has definitely helped steer me back towards purchasing that lens. The price is right, and I've repeatedly read that the build and image quality are nearly unparalleled. In response to your comment regarding only needing the longest focal length on the zoom; I currently always carry an EF 200mm 2.8 USM L II prime with me for that very reason. You've helped reinforce my original plan, and that will be the next lens I purchase.
No problem, and yeah, I used to opt for the 200mm prime over a 70-200, too. (These days I just don't have a use for that focal length so have neither, but when I did I loved that lens.)
There definitely are good reasons for this cheaper 100-400 to exist, but yeah, the old 400 is such a complete package, at such a crazy price now, that it's very hard to imagine you'll be disappointed. There are a lot of great EF mount lenses out there now which are essentially risk-free if you buy and sell used, and I think many people should reconsider their rush to swap everything for new RFs; newer does not always mean better, especially when comparing EF L to RF non-L.