50 mm vs 85 mm for portraits and candid?

Which prime would you prefer to use? My Nikkor 50mm 1.4 is excellent, but I wanted a little more reach but not too much telephoto, would 85mm work well or should reach further, eg 135mm?

I find a 600mm lens perfect for those close up shots of the nose.

Go for 135 mm

Portraits and candids have different needs. Your 50mm on an APS-S sized sensor is considered the ideal for portraits. On a 35mm film or sensor, 85mm is the classic portrait lens. Candids require you to stand off from your subject a bit so that you can shoot them unobtrusively. Otherwise, your subject may react to the presence of your camera, which of course means that it's no longer a candid shot. An 80-200mm zoom is useful in this regard.

My favorite portrait lens was the 105, but you can use a 2x extender on that 50 instead. After the 105 was stolen, I used a 43-86, or later a 28-80, usually racked all the way out.

Portraits are best done with a short telephoto.

On an APS-C then 85mm would be good for portrait work. For candids though I preferred to go wide e.g. Walking through town so around 25mm would be my starting point.

I have both a 50mm f1.8 and an 85mm f1.8 on a D300 (APS-C sensor). The 50mm is fine for close in & the 85mm is excellent for street candids. If you're full frame you might want a little more reach - maybe a 105mm - but on a cropped sensor the 85mm is superb!