Manual Focus K1 II vs. Sony A7 III

Hi

For Pentax, I don't know if it works with m42 lenses, but it works with A lenses : use the Pentax AFA x1.7 for fast autofocus with these manual lenses. Wildlife and macro handheld are sometime easier, but only with central focus. Keep in mind you have to prefocus depending on the lens and the distance. Really useful as you can store all data in the EXIF but take into account the x1.7 magnification ! Screen magnifier are also a great addition on occasions. Only used on the K01 with a magnetic base sticked on the screen for quick access. You should also use it with Sony's screen in Liveview. Catch In Focus is also a great tool when needed.

For Sony, I haven't tried it yet. There is the magnification like with Pentax's liveview, on screen and in the EVF, but there is also the Techart Pro M adapter. It works the same way as the Pentax AFA, but without any contact ! There is a complicated initialisation to do before taking pictures (in fact you select aperture to tell the adapter and the camera what is the focal lenght for IBIS, but if I understand correctly it's not stored in the EXIF). Some improvements needed from Sony and/or the company behind the Techart Pro.

The good news ? Take manual focus Leica M mount lenses (a fine wide angle Voigtlander for example) and use AF with it ... I'll have to see it, but if I read correctly the A7iii is supposed to eye-AF with wide opened lenses at f/1.4 or wider. The lens and the adapter you put on this are limited to 700g: not too bad, but it's not as sturdy as the Pentax's AFA!

If it works as expected, you should add a PK/M adapter to use your small Pentax lenses ... with eye-AF.

In theory, for M42 lenses, just replace the PK/M by an M42/M adapter and you're done.

If you have AIS lenses from your former Nikon's life, choose your adapter.

And a lot of other mounts are compatible...

I hope it helps.

Regards, Fred

PS: I'm still searching on the net the limitations of this adapter and about the Sony's sensor responses in the corner with wide angle lenses. I probably missed a few important shortcomings...