Sigma 70-200mm f2.8 AF0 not AF0 conundreum

[Tampa Steve]

I have a strange issue with my Sigma 70-200mm f2.8 (nonOS) HSM II lens, the lens works fine on my D7200, but recently i purchased a 1.4x converter for a bit more reach for when i went to Fairford airshow. when i put the two together and mount on the camera body i get a F0 error, uhmm - so the 1.4x doesnt work ?, well put on a 140-400mm lens and no f0 error. So I borrowed a friends Sigma 70-200mm f2.8 OS lens and no issues with that one either. What i noticed was if i turned the lens slightly then the f0 error went away, but not practical to do when trying t o track objects. It would seem, as i tried the same combo's on a D7000 and get t eh same results, the issue is with the lens somewhere, but cant understand how it works fine straight on the body, unless the tolerance on the 1.4x is a lot tighter. so where do i go now, I have cleaned the lens contacts but made no difference.


The Lens is way out of warranty, has anyone ever removed the rear of the lens barrel, does it all just fall apart.

 

[Mike.P]

Check the mount screws to see if they need tightening at all ... it was quite a common problem with Sigma before they got all "Arty"

 

[Tampa Steve]

Check the mount screws to see if they need tightening at all ... it was quite a common problem with Sigma before they got all "Arty"

Funny you say that, i had a screw missing from the mount, so contacted Sigma, who kindly sent me a set of new screws, the screw will not 'screw' all the way in, sits proud by about 2-3mm. Its no the screw as tried in a different hole, so tried rotating the screws - all the same.