Tamron 150-600mm f/6.3

[Kayaker72]

I'd have to say the Tamron is likely more targeted at the 70D, 60D, and Rebel crowd. As you go up the class of camera scale most folks will opt for higher grade lenses. It's horses for courses as they say. Some 5D users may pick it, but I would expect there to be fewer of them that do. I can't imagine seeing a modern 1D with this lens.

Dave

I think it provides an interesting alternative to the 100-400L, 400 f/5.6, and Sigma offerings. So there is a nice market there. The reviewer, Dustin Abbott, seems pretty enthralled with it and he typically shoots the 6D. It will get a lot of people that want reach that are on a budget. About the same time I bought my 100-400L, a friend bought the Sigma 150-500mm. He was having some fun with the fact that I paid more for less reach. But, in the end, I use my 100-400L all the time and he was pretty disappointed with the optics of the Sigma. Based on the data to date, I think the Tamron is better than that particular Sigma and like I said above, if I didn't already have the 100-400L, I'd definitely be considering it. But, in the end, I think I am in the market for better optics. Had the Tamron @ 500 mm/600mm with that 95 mm front element been similar to the 100-400L @ 400 mm with the 77 mm front element, I'd probably buy one. But that 25% hit is too much.

Stopping down helps most lenses. Some of the discussion around how much it will help is based on this graph:



I wonder how accurate those data are, given the apparently minor effect of diffraction at f/32...

Exactly what I thought when I saw that graph. Diffraction on most FF cameras starts in at f/10 or so. How is this lens peaking at f/11 to f/16? So that is issue #1. Second issue, even if accurate, that is 2-3 stops of light lost from f/5.6 on the 100-400L. That is significant for moving subjects, such as BIF. Another way to look at it, one of the reasons I moved to the 5DIII was to get the 2 stops of light ISO noise advantage. The 1.6x crop factor applied to 400 mm is 640mm. So, I'd likely be better off with the 7D and 100-400L combo than the 5DIII Tamron combo in terms of both IQ, reach and shutter speed.

I bet there is a pretty good market for this lens. It is affordable and many will buy it for the "600 mm". But pragmatically speaking, it seem like there are better combos out there for me. Where the jury is still out, as Dave mentioned, are those with cropped sensor cameras may covet the 960 mm reach. And perhaps the center IQ will be worth it. It will be interesting to see as more reviews come in.