
My Canon portrait lens recommendations ...
Canon EF 70-200mm f/2.8 L IS USM Lens 
Canon EF 85mm f/1.2 L II USM Lens 
Canon EF 100mm f/2.8 L IS USM Macro Lens 
Canon EF 70-200mm f/2.8 L USM Lens 
Canon EF 24-105mm f/4 L IS USM Lens 
Canon EF 24-70mm f/2.8 L USM Lens 
Canon EF 200mm f/2.0 L IS USM Lens
(large, expensive, awesome image quality)
Canon EF-S 17-55mm f/2.8 IS USM Lens
(EF-S mount only)
Canon EF 85mm f/1.8 USM Lens 
Canon EF 100mm f/2.0 USM Lens 
Canon EF 70-200mm f/4.0 L IS USM Lens 
Canon EF 70-200mm f/4.0 L USM Lens 
Canon EF 135mm f/2.0 L USM Lens 
Canon EF-S 60mm f/2.8 USM Lens
(EF-S mount only)
Canon EF 50mm f/1.4 USM Lens 
Canon EF 50mm f/1.2 L USM Lens 
Canon EF 300mm f/2.8 L IS USM Lens 
Canon EF 24mm f/1.4 L II USM Lens
When taking pictures of people, you don't want to be too close to them.
Getting too close results in a perspective that exaggerates noses and other body parts.
Staying out of their personal space is also a concern.
An uncomfortable subject will not likely photograph well.
On the other hand, you don't want to be too far from your subject.
You want to be able to communicate freely (without needing a cell phone, two-way radio or a megaphone).
You may also have other obstacles preventing you from backing up (such as a wall).
Moving back too far can result in a featureless compression of the subject.
Conventional teaching is that the 85-135mm focal length range is ideal for portrait photography (field of view crop factor included).
I generally agree with this teaching.
I will often use a wider focal length for full body portraits and group pictures and a longer focal length range for tighter-framed portraits such as head shots.
Unless you are using a backdrop, you will probably want to blur the Background.
A wide aperture and/or a long focal length makes this possible.
Wide maximum apertures also make low available light portrait photography possible.
Although I have a couple of f/4 lenses on my recommendation list, the rest are f/2.8 or wider.
My personal favorite portrait lens is the Canon EF 70-200mm f/2.8 L IS USM Lens.
It is sharp, versatile, fast focusing, and has excellent bokeh (background blur quality).
It is not inexpensive or light.
Image stabilization allows indoor available light shooting with this lens.
Some may find the 70-200mm focal length range a bit long for a 1.6x FOVCF body,
but I personally would rather have a slightly long focal length range than a slightly short one.
The Canon EF 85mm f/1.8 USM Lens
is a popular choice when you have the time to position yourself in relation to your subject (sneaker zoom).
It is a very good value lens.
The Canon EF 100mm f/2.0 USM Lens is very similar in performance.
When a wider focal length is required, I usually opt for the
Canon EF 24-70mm f/2.8 L USM Lens,
Canon EF 24-105mm f/4 L IS USM Lens or
Canon EF-S 17-55mm f/2.8 IS USM Lens.
These lenses work very well for groups and full-body portraits.
For the most impressive and differentiating portrait lenses, there are few if any better than the
Canon EF 85mm f/1.2 L II USM Lens and
Canon EF 200mm f/2.0 L IS USM Lens.
Both can deliver very sharp images with a very diffusely blurred background.
For environmental portraits where the foreground and background are desired to be in focus, wider angles are prefered.
These focal lengths do not magnifiy the OOF (Out of Focus) background nearly as much as a telephoto, allowing the big picture to be captured.
If a prime lens can suit your environmental portrait needs, the
Canon EF 24mm f/1.4 L II USM Lens
will perform wonderfully for this use.
Read my full reviews to see which lens(es) are best for you.