Very fine points fivedawgs.
I have among my favorite lenses, a Nikon 105 2,5 lens from yesteryear that produces my best portraits. (that design from the early 50's still being produced today. That tells a little about good design)
The photographer that really wants to take a good portrait can use anything he likes but the one who is not afraid to invest a little into his craft will always get the best results. We can't take photography so lightly that we would substitute a proper lens for a general one and expect the best result. It is also true that many famous photographers of the past did make do with whatever they had and achieved fabulous results. (those were the people that knew how to develop and print as much as they knew how to take the picture).
Today we have so many choices and price ranges that one only needs to put a bit of studying into what they want to do and then prepare for wonderful results. Photography, like any other hobby, can be very rewarding if one puts their heart and passion into it. The magic of all best images come mostly from how we see with our own eye and how to pass that on to the viewer.

I plead guilty: don't and haven't had the 50mm, but a lot of people who swear by them.

However, even back in the old film days, the best length ... the most flattering length ... for portraits were lenses from 85mm to 105mm (although there are people that think 135mm is perfect).

Every manufacturer sold a good 85mm or 90mm, and Nikon's 105mm was spectacular. That was what everyone doing portraits used and I think mostly still do. It's something about the perspective that's uniquely flattering. There are articles about it around the net ... I've read a few, but honestly don't remember where.

The whole issue of perspective is interesting, especially since few of us own full frame cameras, so the "effective" length on our lenses has changed ... but the particular optical qualities of the original length do NOT change. I know that's a hard concept to wrap you head around, but it is true. And worth understanding before investing.

On the other hand, a "nifty fifty" is cheap ... a LOT cheaper than pretty much any other quality glass you can get, so there is that to consider too. The 50mm lens (or thereabouts) was, in previous generations, the "normal" lens, probably the most common lens on every camera. Called normal because it "sees" the world more or less the same way your naked eye will. Whether that's something you want or not is another issue.

I agree with you. I was always told 85 to 105 was the industry standard and it worked perfectly for me. I'm not sure how that relates to crop sensors and their new mm lens sizes though. Maybe a new 50mm on a crop sensor body is about equal to a 90mm in the film days?

I agree with you. I was always told 85 to 105 was the industry standard and it worked perfectly for me. I'm not sure how that relates to crop sensors and their new mm lens sizes though. Maybe a new 50mm on a crop sensor body is about equal to a 90mm in the film days?

This is one of those confusing topics.As I understand it, the optical qualities that are unique to a particular lens length do not alter despite the crop sensors we use. What we see seems "closer" but it isn't, really. We are just seeing a smaller "piece" of the world because of the cropping. There are tons of articles about this and I suggest you read some because this gets a little science-fiction-esque from this point on.

The "effective length" of your lense changes due to crop sensors, but the ACTUAL length doesn't, so whatever special qualities your 90mm lens had in full frame it retains despite the cropping of the sensor. But you have to stand further back to get the same amount of person into the image.

A 50 will never give you the same "look" as an 85 or a 105. You may get the same crop, but you won't get the same DOF or perspective. I don't think I can explain it better, but I'm sure someone else can. Anyone want to brave these waters? They are deep and full of alligators.

How about a simple "skimming the surface" comment to avoid the 'gators: An 85 to 100 (okay, 105) has a special "look" because it lacks wide angle distortion that a shorter focal length would start to create and it lacks the telephoto "mashed depth of field" look that a longer focal length would start to create. 85 to 100 resides nicely right in the middle with the best of all worlds for natural looking portraiture with neither of those negative factors involved.

How's that?

That's GREAT. Wow. Clear and I actually UNDERSTOOD it. This is one of those baffling subjects for me. There are physics involved and that was not one of the things I was ever good at.