Hmmm... I wonder kung pupwede yung mga 'analog' experiences ko with my Nikon F2...
I had 4 favorite lenses that I used for portraiture. Of course, the standard 'noob' lens is the 50mm 1.4 Nikkor which some consider to be too wide, but I found out that it was right at times where you want some background scenery, but not a lot. Wide open settings provided good out-of-focus backgrounds, providing you are relatively close to the subject, but using smaller apertures yielded some details in the background, especially if that is what you're after.
I also had a Tamron 35-105 f3.5 which was not really the best, but I found out that the best focal length for portraits was the one with the same focal length as my own eye, which in this case was approximately 75mm. Once the camera saw the same thing as my eye, I discovered I could compose portraits better. That particular lens, however, had something I would call a slightly hazy character which sometimes worked for certain situations but under good lighting, center sharpness was quite good. (This zoom also had a macro mode which I used heavily for nature shots, usually orchids.)
My 3rd favorite was my 28mm f2.8 Nikkor. This is too wide for some, but I discovered that it had excellent edge diffraction characteristics. Straight lines at the extreme edges of the field of view, which I found to be rare with most wide angles. Though not exactly a portrait lens, the edge diffraction was perfect if you wanted your subject to be off center with lots of background detail. My only gripe is that f2.8 will sometimes give you a fairly low shutter speeds under ambient low lighting conditions.
Lastly, my 135mm, which is good for stolen shots. One thing about teles is how they tend to 'compress' the background, bringing it 'closer' to the foreground. If you can, try to compare the difference between tele and 50mm shots using the same subject scenery. One good thing about teles is that you can get really out-of-focus backgrounds when wide open. Too much tele, however, and your subject will appear 2-dimensional instead of having some depth to them.
The thing with portraits is to have the sharpest image available. That's why I prefer fixed focal length lenses for the job. Zooms can sometimes be a little fuzzy plus their edge diffraction can make curves out of straight lines.
Just sharing my experiences...