7D, Tamron 100-400 slowing af speed at 400

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Walt_A Senior Member • Posts: 1,976
7D, Tamron 100-400 slowing af speed at 400

Hi, I've got the original version of the 7D along with the Tamron 100-400 F4.5-6.3 VC. It's working pretty good but I keep reading about it being a fast af lens and my setup just isn't. I found this youtube video showing the AF speed at 400 on the Tamron and the sigma, I don't know what body it was tested on but it looks pretty quick. Mine is like that at 100, but slows down as I move to 400. Taking something close to 1 second to travel the full range, i.e. Inf to close or close to inf, giving about 2 seconds to do the whole range inf back to inf.

When an object is out of focus but the af system can detect where it is and move direct there rather than searching, it seems fast, but having to search seems unusually slow.

Reading lenstip.com's review of the tamron they say it takes about 0.5 second to cover the range and they also tested it with a 50D, so older af system than my 7D, but made no mention of it being slower on that body.

I thought it might be that the lens was F6.3 at 400 where the 7D was rated for F5.6 so backed off to around 280 where it registers F5.6 and it is still slower than that video at 400 and when I use it at 100.

My Canon 200 F2.8 ii USM L seems to work as the reviews suggest, nice and quick on the 7D.

I tried the Tamron on my old 650 film camera and it works similar to the 7d just a bit slower. i.e. quick at 100 slowing down noticeably at 400, and a gradual slowing through the range as I move to 400.

So, do any of you use the original 7D with the tamron and does your af speed at 400 match that video?

I wondering if the Lens is at fault, my 7D has an issue or if this is just to be expected and I need to move to a more modern af system 80D/7Dii to see the speed benefits? Unfortunately I don't have access to another body or another 100-400 to see where, if at all, the problem lies.

Thanks

Canon EOS 50D Canon EOS 7D
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