[UncleVanya]

No he was talking about Pentax lenses. I have a lot of them in K and M42 mount. However they are all MF.

There are af adapters for Leica M lenses on Sony that can be adapted to K mount. Used you might find one in your price range to allow the use of the existing options you have.

[Raffwal]

Sorry, but why not longer than 55mm? Many feel that a good focal length for portraits is somewhere around 80 to 100 mm (35 mm equivalent).

[Prince Harbinger]

Sorry, but why not longer than 55mm? Many feel that a good focal length for portraits is somewhere around 80 to 100 mm (35 mm equivalent).

Keep in mind I'm using a APS-C camera.

[UncleVanya]

Keep in mind I'm using a APS-C camera.

Keep in mind that even in the film era many used a 135 as a portrait lens. The Nikon 105 isn't that long but was highly prised for portraits as well.

A 70mm on crop is roughly equivalent to the 105 on 35mm film. An 85mm on crop acts like a 130mm or so. The longer lenses do require a little more distance, but it's doable.

There's nothing wrong with a 55mm lens on crop for portraits but a little longer works as well.

[BigMackCam]

If you happen to own one of the AF screw-drive-enabled A-to-E-mount adaptors - such as the LA-EA2 or LA-EA4 - I would go with a good used copy of the pre-1990 Minolta AF 50mm f/1.4 (the one with the hard, toothed focusing ring and orange "AF" marking). You should be able to find an excellent example for around $150, give or take a few bucks. It's getting old now, yes... and it uses screw-drive focusing... but image quality is excellent for your purposes and it's robustly built; plus the pre-1990 version produces nice diffraction stars at narrow apertures (unlike post-1990 models and the re-badged Sony version with rounded diaphragm blades). A classic "fast fifty", the field of view is ideal for portaiture on APS-C, and you'll get nice bokeh at faster aperture settings (even a little swirl wide open in the right settings )...