Tamron SP 150-600mm Di VC USD

So I presume that since I have received no responses to my 2 separate inquiries regarding the Tamron on 5DIII, nobody really shoots this lens here on a 5DIII.
I should probably find people here locally with 5DIII bodies and try to test my lens on theirs, I guess.

gabebalazs wrote in post #17475724
So I presume that since I have received no responses to my 2 separate inquiries regarding the Tamron on 5DIII, nobody really shoots this lens here on a 5DIII.
I should probably find people here locally with 5DIII bodies and try to test my lens on theirs, I guess.

I'll give it a try today or tomorrow, most of our snow is gone now but I'll find something to shoot. Used that combo at a airshow with no problems.

gabebalazs wrote in post #17475724
So I presume that since I have received no responses to my 2 separate inquiries regarding the Tamron on 5DIII, nobody really shoots this lens here on a 5DIII.
I should probably find people here locally with 5DIII bodies and try to test my lens on theirs, I guess.

I've used it with my 5D3 and have not experienced the behavior you describe...though I haven't intentionally tried to recreate it since you posted as it's been gray and overcast here. If the sun ever returns, I'll try it.

Finally got around to stacking some images of the Orion nebula with the tamron. 20, one minute exposures with a skytracker.

Wow! That is superb!

peteg1 wrote in post #17475746
I'll give it a try today or tomorrow, most of our snow is gone now but I'll find something to shoot. Used that combo at a airshow with no problems.

Thank you guys, looking forward to the results.

gabebalazs wrote in post #17476039
Thank you guys, looking forward to the results.

Well I never knew of this issue with mine but with the bright sun on my white Xterra it wouldn't focus, just had to drop down a little to the top of my tire and it was fine. I would say 7 of 10 times it would not focus on very sunlit white.


No focus.

Thanks for the test. In your case though it looks like there is no contrast on the side of your Xterra if that's where you tried to focus (unless there is some dirt on it), so it may be logical that it misses. Did you by chance try other AF points aiming at the same area?

I'm curious. You guys who bought Canon USA models, what model number shows on that little white card that also states the serial number say? Mine says A011E which I thought it should say A011C.

gabebalazs wrote in post #17476406
Thanks for the test. In your case though it looks like there is no contrast on the side of your Xterra if that's where you tried to focus (unless there is some dirt on it), so it may be logical that it misses. Did you by chance try other AF points aiming at the same area?

Did not try the other AF points. I did try my 7D mkII on the same spot and it AF everytime.

It's not going to focus on pure white... it needs contrast to focus.

Most landscape or moon shots are much better with something else in the frame.

peteg1 wrote in post #17476550
Did not try the other AF points. I did try my 7D mkII on the same spot and it AF everytime.

Even with the best L lens it won't focus if there is no contrast at all like here, depend only about the AF capabilities of the camera, not the lens

That's exactly why we're doing these tests; we are trying to figure out what's happening. I wish Pete had tried the neighboring AF points on his 5DIII. But it's useful info that his 7DII focused on the same spot every time, so there must have been some contrast there (dirt maybe?). I also tried the Tamron 150-600 a couple weeks ago on CPS loan 7DII and there was no issue with the center AF point and bright subjects.

Another easy way to test this is to try to AF on a light bulb that is turned on. Yes, it is bright but still has descent contrast ( the filament, mount, or the actual curves or spiral of a CF bulb) so any of my 5DIII AF points work fine with the Tamron lens, except the center, which half the time has issues. Again, same lens on other bodies, no issue at all. A different lens (400 5.6L, Sigma 120-300 2.8 OS) on the 5DIII, center AF point, no issue. Puzzling. I wonder if it's a metering issue affecting AF, but why only the center point???

Advice please I am looking to add a 1.4 x convertor to this lens for Moon shots. My canon 1.4 does not fit..arrrr. So I need another one, and not sure which one....Kenko Teleplus DGX/DG Pro-300 or Sigma 1.4x EX DG Tele Converter. Help !