Portrait lens choice for 1.6 crop

I made a thread earlier asking about a Tamron 17-50 lens. I am wanting to do portraits. After much research I am thinking something else might be better?

For doing portraits on a crop camera, would the 85mm 1.8 be better?
It does have the much better AF and better build quality. It is cheaper. Larger max aperture. The only con I can think of is it will be very long on a crop body and a little bit harder to get anything more than half body indoors. But then I figure for a full body I can just use my 50mm 1.8. I can imagine the 85mm 1.8 will be amazing outside where I will have more room.

So this would give me:
85mm 1.8 (indoor/half body outdoor/full body)
50mm 1.8 (indoor/full body)
18-200 (walkaround)
70-300 (wildlife)

However, if I went with the Tamron 17-50 I would likely sell my 18-200 and would be left with:
17-50 2.8 (indoor/full body) (walkaround)
50mm 1.8 (indoor/full body)
70-300 (wildlife)

I do fear the distortion that may come from the 17-50 compared to the 85 along with the poor AF compared to Canons USM. I would also be more restricted as my "walkaround" lens.

If you want a dedicated portrait lens, 85 1.8 is a great choice.

What you need to be aware of is 17-50 is a general walkaround lens, different lens for different use and situation.

Every lens has its own place.

I voted based on using it for portraits, not which is best for your situation... the 85mm is great

Rent both for a weekend and see what you like.

85 1.8 is the sharpest lens I own and gets used a lot but I am shooting FF. If you have the room to work with outdoors, I think you'd be much happier with it's IQ compared with the zoom.

85-110mm is great for shooting 'portraits' with FF camera, not with APS-C -- which need FL which are1/1.6x as long in order to shoot the same photo from the same camera location as the FF camera!

Classically, 85-110 lenses gained the label during 135 format days as a 'portrait' lens, referring to the tightness of framing achieved in the studio at a shooting distance of about 8-10'. This distance permitted the photographer to easily and quickly move forward to adjust lights or to adjust pose in the potrait sitter. The label 'portrait lens' applies ONLY IN THE CONTEXT OF 135 format size (24mm x 36mm), and does not apply in any other format size context. In fact, the label used on Canon web sites is always in the context of the 24x36mm frame size, although they fit on APS-C and APS-H cameras, too. For example, 24mm is 'wide angle' on FF, but it is 'normal' on APS-C...and it is in the 'wide angle' category of lenses, not 'standard lenses'. 85mm on APS-C is 'medium telephoto', equivalent to 135mm on FF, which is more likely used for a tightly framed headshot with that format.

Yes, some pros like to shoot with longer lenses from farther distances. Some fashion photographers do this a lot particularly outdoors. Working with pro models they pose themselves in ever-changing positions, so the photographer only needs to occasionally shout out a broad suggestion of pose or actions. Pros on location often have assisitants handling lighting gear, so they don't need to run back and forth as much as a studio pro.

Some photographers call them 'portraits' but they really mean 'candids' because the person being photographed might not even be aware of the presence of someone on the street 20' away with a camera, in part oftentimes because the photographer is uncomfortable being closer and interacting with that person! The 85mm on APS-C is better for shooting the on-street no-awareness-of-photographer candid photos that some folks like to shoot.