bsbeamer said:
Wish they'd include a built-in teleconverter on some of these longer 3rd party zoom lenses.
If you want the price to go up by 2-3x, sure.
The mark I Canon 100-400 isn't very good. The Sigma and Tamron 150-600s which retail for around the same price point are categorically better, and if it's the long range you're concerned about (i.e. you're mostly looking at that 400mm end) then the old Canon 400mm f/5.6 is so much sharper than the Canon 100-400 mkI that you can afford to simply upres it to the equivalent of 500mm+ and still get a sharper, clearer image than the 100-400 simply at 400. You give up IS for that, but given the kinds of shutter speeds you usually use for the sort of subjects these lenses are used with—sports, wildlife—IS is of limited value anyway.
Khufu said:
I played around with a Tamron >300mm zoom a few years ago with the idea of it maybe being usable for video; whilst engaged the IS/VC held for a second or so at a time then jumped, held, jumped... totally unusable for video (unless purely to document, rather than have smooth footage)
Does anyone have any insight into how the current Tamron and Sigma lenses' IS/VC/OS behaves, and is there a name for this above-mentioned behaviour?!
Tamron's is far, far better than it used to be, and in many cases better than Canon's. It's quieter and smoother, though in the most extreme cases that does appear to come at the cost of some effectiveness. In my experience, I'll get about an extra half stop of stabilisation out of Canon compared to (new) Tamron; YMMV depending on how good you are at holding the camera still yourself and just how far you expect to be able to stress the system. I rarely need more than a stop and a half of stabilisation anyway, so both do me just fine, and given the Tamrons are quieter and a touch smoother, they're currently the IS system I favour. Bear in mind the Tamron (and Sigma, for that matter) can have their IS somewhat customised via their USB interfaces, while Canon's IS behaviour is set in stone.
There is one exception, which is the Tamron 85mm. For some reason, the VC on that lens drops the image quality quite noticeably, similar to the kind of difference you'd expect between stopping down and using a lens wide open. Luckily that lens is optically
incredible anyway, so the 'worse' optics with VC turned on are still better than any of the three Canon 85mms (still not as good as the Sigma or Zeiss, of course), but it's something to be aware of. For 1080p video you'll never notice it, but for 4K or for stills, you can see the difference in resolution and contrast between VC on and off.
As for Sigma, it's more random. Some of their OS is fine, and for other lenses it's so loud and clunky you wonder why they bothered. Funnily enough it's the cheaper lenses which seem to have the quieter and smoother OS (though, like Tamron, it's also slightly less effective in those lenses) while their more expensive lenses have dodgier OS (though it's fully effective in them).
In other words, it's a lot like the AF situation. Sigma focus on getting the optics as good as possible for the price point, but the electronics aren't as well developed as a result. Tamron do a better job with the electronics, but their optical quality is below Sigma. (Again, though, that still leaves them ahead of Canon in many cases, since Canon are still using some lens designs form twenty years ago and really need to bring many lenses up-to-date.)
I will say that if stabilised video is that important to you, get a GH5 or Sony. They're far, far better for it, especially if you record in 4k but publish in 1080p; the huge amount of resolution that gives you for software stabilisation should not be underestimated. Right now, a GH5 or α7/9 with Sigma's prime lenses is basically the very best hand-held 4K video system you can get. (Obviously you can get nicer systems if you're going to include dedicated video cameras, but that's a whole 'nother beast and I imagine if you were in the market for one of those you wouldn't be looking at this Tamron anyway.) You get stabilisation on everything, better video quality, better manual focus aids, and even for autofocus, being mirrorless solves the accuracy problems of the Sigmas, leaving you to enjoy the full quality of their optics.
Plainsman said:
another unimaginative product that won't sell in large numbers - market is saturated with these zooms
... Except they do sell, massively. The other Tamron and Sigma telephoto zooms sell in
huge numbers, relative to the Canon and Nikon equivalents, and there's no reason to believe a 100-400 won't either.
What you complain about being "unimaginative" is precisely
why these lenses sell. They give a focal range and/or features people want at a price the first-parties won't match, plus a better warranty as well, in most countries.
24mm, 35mm, 50mm, 85mm, 135mm, 24-70mm, 24-105mm, 70-200mm; all are "unimaginative". And they're all the top-sellers. Funnily enough when Tamron did break the mold and put out the 45mm in place of a 50mm, it proved nowhere near as popular and hasn't sold half as well as their more common focal lengths. Ever wonder why third-parties rarely make a 28mm, 100mm non-macro, and stopped making their 50-150mms? Those focal lengths either fell out of fashion or where never in fashion in the first place, and people buy whatever is popular. Once-upon-a-time, 100mm was 'the' portrait focal length. Now it's 85mm and if you want to make money, you build an 85mm lens. Canon's own 100-400mm, for years, was objectively worse than all their other lenses covering the same or similar range, yet it was still their best-selling telephoto lens by miles. The mk II is significantly better than the mk I but it hasn't been selling anywhere near as well, in large part (anecdotally according to several stores I've spoken to, as well as a couple of Canon reps) because they put the price up so high. (Same goes for the 35mm f/2 IS, which is only just now starting to pick up sales after a couple of years of the price diving.)
If Tamron can make a 100-400 which is better than the old Canon and at a similar price—it doesn't need to match the new Canon—then that's a sure-fire hit. Given their recent developments, it's a pretty safe bet that this lens will at the very least beat the mk I Canon (their 150-600 G2 already does), and likely give the mk II some decent competition and do so at a price which fits the general market much better.
(Disclaimer: I'm more of a prime guy and am very happy with the Canon 500mm and occasionally renting the Canon 600mm for these kinds of subjects, but if I ever have to downsize, I'll be going with the Tamrons. Every time I use them they do nothing but impress, while Canon never seem any better considering the much higher price tags. So, even though right now what I
own are all Canon, I've used the Tamrons {and Sigmas} enough to know that if I were starting over today I'd be going all-third-party, and hence I encourage everyone else to at least give them serious consideration. Even when you have the money for the first-party options, some of these third-party versions are simply better, even before you factor in the prices. This is, if anything, more a reflection of how slow Canon have been to update many of their own lenses.)