1.4x - Minolta APO II v Kenko DGX

I have a Kenko 1.4x DGX converter (not Pro 300) and it works pretty well. However, I have recently become the proud owner of a couple of Minolta primes that are compatible with the APO II converters (200/2.8 HS APO & 300/4 HS APO) and am wondering if I will gain significantly better performance from a Minolta APO II teleconverter.

I also have a basic Kenko MC7 2x which I am less happy with and was considering an upgrade to the DGX version (based on my experience with the 1.4x).

The Kenko route is obviously very attractive - providing the results are up to scratch. I have plenty of lenses that are incompatible with the Minolta converters.

I have the Kenko DGX 1.4x, the Minolta APO 1.4x APO, and the Kenko Pro 300 2x converters. I agree that the DGX 1.4x works pretty well and fits nearly all my lenses. I use the APO 1.4x with my Minolta 400 f4.5 (High Speed), and it works quite well - fast focus and good image quality. I purposely got the original APO TC because a friend who had both said the APO actually focused faster because it didn't use the 2:1 gear reduction in the APO II. The gear reduction was apparently to prevent over-shooting focus on high-speed Minolta lenses, but that never seems to happen anyway. The DGX 1.4x on the Min 400 is slightly worse in image quality but focuses reasonably well. The only lens I have that the APO TC will fit (other than the 400) is my Sony 70-400 (manual focus only).

The Kenko Pro 300 2x is my least-used TC. The image quality is adequate with the Minolta 400, and it will auto-focus (but quite slowly). It's hard to get sharp shots with other lenses, and it doesn't fit any of my Sony/Minolta lenses (other than 70-400). It did fit all my Sigma and Tamron lenses I tried, but only the Tamron 70-200 (screw-drive) lens would auto-focus. It's a nice TC, and reports exif correctly, but it is just not really useful. I suspect the DGX 2x would fit more lenses, but probably would also not produce sharp photos most of the time. Your Minolta 200 and 300/HS lenses might produce useable results, though. Good luck if you spring for it.

I have the 200/2.8 and 300/4 and have been offered a Minolta 2x APO II at a decent price, so I have gone for it. I'm a little concerned about AF with the 300, but I'm not so worried about AF speed.

robberly12 wrote: I guess you will find out!

I have indeed found out.

As feared the 300/4 will not AF with the 2x APO II. It will, of course MF and I have to say the results are impressive.

With my 200/2.8 AF is sedate, it glides into focus rather than snaps - but, to be fair, so does the lens without the teleconverter. Most of the time AF it finds focus well and minor adjustments to, for instance, follow a moving bicycle, work well.

Although disappointed at the lack of AF with the 300/4 I am impressed by the optical quality, the combination with the 200/2.8 gives me a prime quality 400/5.6 which I am very happy with. This converter is in another class to my Kenko MC7 (I'd say 1st Class v 3rd).

Even though I only have the two compatible lenses I shall now be on the alert for a well priced 1.4x.

Edited by Phil Wood - 09 May 2022 at 21:09