Canon 7D MK2 and Sigma 150-600 ĺens and SIGMA T -1401 Tele probem

Hi everyone, I am having a problem with the Canon 7D MK2, Sigma 150-600 lens and the TC-1401 tele. I doesn't work automatically after 400mm, it searching for a focus spot. If anyone working this setup at 600mm automatically please pass on wnat you do to make it work.
Sigma said it takes a moment and then it works. (Wrong) The Sigma changes from F8 to
F9 at 400mm and the MK2 stops working at F8.

The second question is, anyone using the Tamron 150-600mm G2 and their tele on the 7D MK2? How does it work well and fast. I shot BIF and I want a setup that works fast..
Thank you in advance. .

That combo should work with center point with or without expansion. Make sure you have Lens Drive when AF Impossible enabled and that you are zoomed out to 150 when you attach the lens/tc to the camera.

What happens when you try to AF, are you getting an error or is the lens just hunting then stops trying?

-Joe

When you say " it doesn't work " I assume that you mean it doesn't autofocus. I tried the Sigma 150-600mm with their 1.4 teleconverter and the Tamron 150-600 G2 with their 1.4 teleconverter last fall and found that both of these combos would only autofocus in very bright contrasty light so I returned both of these to the dealer. I called Sigma and was told that was normal. Tamron said pretty much the same thing. Of the two lenses with teleconverters the Sigma combination seemed to be a little sharper but to be fair I didn't micro adjust either lens. On both lenses I felt that cropping the bare lens would produce as good a quality as using it with the teleconverter. That was my experience, but you might want to look up UK_MARK . He gets phenomenal results with the Sigma C and 1.4 TC. You can find some of his shots in the lens sample forum. I would not use either combination for birds in flight.

I am searching, no errors. I will check Lens Drive when AF Impossible enabled.
Thank you.

Larry, thank you. I got the same feelings. I will look up UK_MARK. I think I will keep the Sigma lens.

If the camera sees that you are past f8 at 400mm, it won't even attempt to AF, you are outside its configuration at that point. If you can get the TC to not report (tape over the last 3 pins, for example), the camera won't know you have a TC hooked up and will think you are still at f6.3. It will try to AF at that point. However, you still physically have 1 full stop less light to work with, and the AF system most likely will struggle unless you are in midday sun.