1.4 TC for Tamron 150-600mm

Is there a brand of teleconverter rated at 1.4 that would work on my Tamron 150-600mm and 5D III combo?
Would it auto-focus? If so, is it slow to AF?

guntoter wrote in post #17984524
Is there a brand of teleconverter rated at 1.4 that would work on my Tamron 150-600mm and 5D III combo?
Would it auto-focus? If so, is it slow to AF?

5DIII will autofocus at f/8. So no.
It might with this combo, but it's going to be damn frustrating..

My Canon L 1.4 won't fit physically on the Tammy due to larger caliber of that protruding lens elements. I use both Tamron's 1.4 and 2 x TC, individually or in combination with no problem.
With 1.4 TC AF is OK but I prefer to turn it to manual in either case and unlike Canon's lenses that when you add TC, the EXIF shows the correct sum of the Focal Length (Say 600mm as 1200mm with 2x), here with Tammy FL remains the same on EXIF, no matter what TC I add on it.

guntoter wrote in post #17984524
Is there a brand of teleconverter rated at 1.4 that would work on my Tamron 150-600mm and 5D III combo?
Would it auto-focus? If so, is it slow to AF?

Heya,

I use a Kenko PRO 300 Series 1.4x TC with my Tamron 150-600 and it works. The 5D3 can retain AF at F8, so you're fine. Just don't expect it to perform great. It's reasonably sharp, but definitely takes a hit. The AF speed and accuracy takes a pretty good hit. If you're in really good light, lots of contrast, you can get decent shots without too much frustration. But if it's meh light or even average, expect to get some hunting and miss focuses pretty often.

I did it with a 1D II for a while. Ultimately I found the performance drop to make it not worth it.

The only time I use a TC with the Tamron, at all, now is basically for manual focus jobs of very bright things not moving too fast. Like the moon basically.

Recently I stacked Kenko PRO 300 2.0x & 1.4x with the Tamron 150-600, parked at 500mm (a bit sharper than 600mm which normally I can't tell but when stacking TC's it shows more) to make it a 1400mm physical lens for moon stuff.

IMAGE LINK: https://flic.kr/p/Fiyt​RE

I used a Tamron non-pro series 1.4X TC with my Tamron and it autofocused with my 7DII, though it was very slow, inaccurate and had much lower IQ than the bare lens.

Tried it with an older Tamron non reporting 1.4 TC and it focused fine but there was quite a hit on IQ, so much so that in my case cropping would definitely be the better option. There is a guy on the 7D II forum that shoots with a Kenko and gets great results. He told me it would not AF with the center point but it would AF with the outer point. Can't think of his user name off hand I'll have to look it up.

His user name is alexander6868. He has several photos posted using the 1.4 on the Tamron 150-600. I was just wondering if that new Sigma TC would work on the Tamron and what theresults would be.

Thanks everyone for the answers. Sounds like it would be a compromise as best for AF with any of the TC's that would fit. I have a Canon 2x III, but as someone mentioned, it will not fit the Tammy.