[stevebrot]

With your KP, either of the two primes may be used for portraiture as might the zoom at its wider settings. As far as basic technique, close distance is not your friend due to exaggeration of features (e.g. nose) and crowding the subject. Alternatively, longer focal lengths are a challenge due to working distance (too small a studio).


Steve

[Sandy Hancock]

For a crop camera, your DA 50/1.8 and DA* 50-135/2.8 will cover most of your typical portrait needs admirably. The DA 20-40/2.8-4.0 Limited will comfortably cover the rest.

There are, of course, many others. The DA* 55/1.4, DA 70/2.4 Limited and FA 77/1.8 Limited are right in the pocket. A cheap old Helios 58/2.0 can give spectacular results on crop as well.

Don't forget that great portraiture has more to do with engagement with the subject, lighting, pose, context and attention to the background than which lens is used.

[caliscouser]

I would not buy any more lenses. The ones you have are great portrait lenses.

This.

All those lenses can be used for portraiture and each brings different things to the table.
Use them, get to know their strengths and weaknesses and the question will answer itself

[sbh]

The KP image quality is remarkable and worth good glass. If you are into details of colour and contrast then there is only the DA*55. no other lens does portraits as good as this lens on apsc.

[MaineNative]

My biggest challenge with portraits is getting the correct depth of field. I have a 28-90/2.8 that I use on my full-frame K-1.

You want faces to be sharp, but also the background to be blurry (ie, good Bokeh). Because I am using a zoom, if the Bokeh isn’t good, I can use a longer focal length, move further away and get better bokeh. I agree the lenses you have are a great start. Play with them to figure out which lens gives you the best depth of field/bokeh. It will vary depending on how far the person is from you and if you are taking a picture of one person or a group. Eventually you’ll learn which lens or settings to use without too much trial and error.

[DeadJohn]

...Should I buy another one?...

I often suggest practice with your existing lenses first, see if/how those lenses hold you back, then decide what lens to buy next.

Your 50-135 is a good portrait lens; it might not hold you back at all. If that lens is sometimes too large try your 50/1.8. You'll be able to get thin depth of field if you want that in portraits, and stop down when you want more depth of field.

[mikesbike]

Your new DA 20-40mm Ltd and your quite inexpensive DA 50mm f/1.8 can supply very fine portrait results. The ability to open up to f/1.8 aperture is an advantage when you want to reduce depth-of-field (DOF) making for a shallower range where the background and foreground will be blurrier to make your subject stand out more dramatically from it. Then you have more choices as to how much or how little you want your background to be recognizable in your shot. Sometimes you want it recognizable to give your shot context and/or the environment provides added pleasantry, but still want it less sharp so your subject will still stand out. 50mm will also allow you to shoot at more distance from your subject yet still get a good head and shoulders type portrait.

OTOH, your new DA 20-40mm Ltd is a superb lens, and especially good when you want more environmental surroundings and the ability to adjust framing which zoom lenses offer, as well as its fine imaging, as the above example illustrates so well.

[Oktyabr]

I have been wanting that combo for such a long time. I use my K1 exclusively and have K5IIs which I do not use at all. I might get the KP just to pair it with the 20-40. I have neither. So I have to save up!

Fantastic shot by the way.

Thanks!

[Class A]

The recommended focal length for portraits on FF is around the 85mm mark...

So @bcernucan 's KP needs a ~57mm lens to achieve the same field of view, i.e., the same shooting distance for the same framing.

Some people recommend the DA* 55/1.4 but @bcernucan, if I were you, I'd make sure I'd like the bokeh of the DA* 55/1.4. I personally, don't like it and think there are better choices. If you don't mind manual focusing, the K 55/1.8 is a great lens, AFAIC.

Note that the classic 85mm focal length (for full frame) recommendation is just one of many choices. Many famous portrait photographers uses smaller focal lengths to create a more personal perspective. I'd say for APS-C anything between 28mm and 60mm should be considered non-controversial.

[5r82]

All lenses that you have are good for portraits. It's up to you to see what you really like.