A-Mount Teleconverters Guide

My Kenko 1.4x MC4 DGX will AF nicely with my Tamron SP 70-200 2.8 (A009) as well as with the 90mm macro (F004) on different A-mount bodies. AF also partly works on the Tamron 160-600 (A011) - up to about the 300mm zoom setting.

All these lenses have their own USD motors.

If it doesn't work for you, it may be because of some still unrecognized defect in your equipment. Could be either the 1.4x DGX or the camera.

I think Kenko had trouble with the Sony comms protocol because they deleted all A-mount TCs from their sales list. on the older ones, WYGIWYG!

amrep wrote: Miranda F wrote: I think Kenko had trouble with the Sony comms protocol because they deleted all A-mount TCs from their sales list. on the older ones, WYGIWYG! In my opinion that's an unfounded speculation. The Kenko TC's generally works well on all Sony A-mount bodies.

Given how many iterations they had of their TC hardware and firmware and how every version has compatibility issues with some lenses, I'd say it was well-founded speculation; but I agree that sales volume was likely to be a contributory factor.
And I'd argue with 'generally'. The later TCs work well on most older lenses but whichever one you pick (especially if you pick one up s/h without much provenance) you are likely to find issues with some lens or other.

Yes, I agree.

I did misread. Please disregard.   It was showing that an F2 would become f4 which is a larger stop than 6.3.

pbcbob wrote: I am sure this has already been answered. In the introduction to teleconverters it states that the minimum aperture to enable auto-focus is 6.3. It then gives an example that a 2X teleconverter will work on an F4 lens. Two f stops would make it F8 which is too small. I just tried the Minolta 2X teleconverter on my 300mm F4 and it will not auto-focus. Comments appreciated. I sure hope I am not misreading the narrative.

That part of the guide here is inaccurate. There's no definite limit. Sony (and Minolta) arbitrarily disable AF with their teleconverters, but the Kenko teleconverters don't do that. The AF sensors still work a bit beyond an effective f/11. Most of the points have effective apertures around f/5.6, so performance degrades at smaller apertures, but they work pretty well at f/8 still.

Contrary to poster above me the chipped Kenko teleconverters report the effective aperture, in fact they report a slightly smaller effective aperture than the actual one. The reported effective aperture is not used by the camera to turn off the AF system.

Even old Kenko 5-pin 2X chipped teleconverters allow AF with F4 lenses on Minolta film cameras.

I do have a Kenko DG teleconverter that just passes through the lens communications and AF works worse with it, than with the chipped teleconverters.

Edited by QuietOC - 28 April 2019 at 21:08

Samyang 24mm Tilt Shift A-mount fits & operates on Minolta/Sony TC14 and TC20.
Since there is only one TS lens available for A-mount this helps you to create different focal lengths.
As usual the TC20 degrades image quality more than the TC14 but it works both in tilt as in shift mode.
Works on both A99 and A99II, will probably work on APS-C also.
The Samyang is fully manual lens so differences in type 1, type 2 and Sony brand for gearing, D-chip and SSM support are irrelevant, they all work the alike.