jdnan wrote in post #18579444
I guess the obvious follow up question is do those of you who have used both the Tamron & the Canon 1st gen 100-400 think the Tamron is superior? I have a local guy with a pristine 1st gen Canon asking $650.
The first gen Canon 100-400 was a step above even the best of the consumer tele-zooms of the time that it was launched, and even until three or four years ago. But it was long in service, and standards improved. It always had some failings, it never played well with either filters or teleconverters, and by current standards was quite soft at the long end. Still it was a good lens, or Canon wouldn't have been selling them in the numbers they did, for as long as they did. They only upgraded it after all when they actually had some competition.
The competition initially came in the form of the 150-600's from first Tamron, then Sigma. I never owned the Canon 100-400, but did rent it quite a few times, so have some experience with it. Optically it and the Tamron G1 were very close at 400mm although most seem to give the Canon the edge. The real disappointment for me with the G1, and the reason I don't own one was the VC.
There is no panning mode for the Tamron VC. The shorter lenses, the 70-200 and 70-300's have auto switching to a propper panning mode. I mostly need to shoot at shutter speeds less than 1/200, and often still need to add a 1.5× crop even at 600mm and panning. So for me optical image stabilisation is important in this situation. I rented the Tamron to try out, and the feedback vibration caused by leaving the VC switched on ruined a vast majority of the photos I took that day. It was really only the shots where the pan hadn't started yet, or shots at over 1/500s that worked. Tamron was unable to fix this, although they did add a firmware update that detected panning, and turned the VC off for you.
The other option became the Sigma 150-600's, I went with the C version. I could not afford the extra for the S, nor could I really mange the extra weight. IMO the Sigma is much better optically than either the Tamron 150-600 G1 or the Canon 100-400. It has very effective OS, with both mode 1 and 2, so allows panning. It also has the dock option for both firmware updates and to set custom MFA settings for multiple focal lengths, and focal distances, with a total of 16 values. There are some marginal optical quality gains with the Sigma S, but most of the improvements over the C are in build quality, with a full brass chassis and mount. AS I said I now shoot the Sigma 150-600 C.
The second gen Canon then came along and is better optically than any of the other new competing lenses, but of course has the price tag to go with that status. Of that batch of lenses I would rate them in order from best to worse: Canon 100-400 II, Sigma 150-600 S, Sigma C, Canon 100-400 I, Tamron 150-600 G1. Tamron's release of the G2 version fixed most of the things that made the G1 not so good. Better optically, VC with panning mode, and of course the dock option for upgrades, although I don't think you get the MFA and other lens setup adjustments you get from the Sigma dock. The Tamron seems to come closest to the Sigma S in performance and also price, but I haven't tried one.
With the experience gained from the 150-600 lenses both Tamron and Sigma have gone ahead and produced direct competitors for the Canon 100-400 I, and based on my experiences with the big brothers, combined with the reports that I have read, I would have to say that at the same price given the choice I would take one of the new Tamrons or Sigmas over a second hand Canon gen one any day. Personally I would want any second hand Canon 100-400 L I to be at least £/$100 cheaper than one of the new Sigmas or Tamrons before I would even think of looking at it.
Oh and to add to Wilt's post about the directionality of zoom and focus rings, I have, or have tried/used, Sigma lenses with rings that work in all four possible different directional combinations. Sometimes different versions of the same lens are even different. I looked at the 50-150 ƒ/2.8, it came in straight, HSM and OS HSM versions, and all three are different in ring directions.