The most classic portrait focal length is 85mm, but 135mm lenses have a special place in the heart of a lot of photographers. If you have not tried one in your own work, check out this excellent video that discusses the benefits of working with one and offers some helpful tips.
Coming to you from Julia Trotti, this great video discusses the benefits of using a 135mm lens for portraits as well as some tips for creating effective compositions with one. Traditionally, 85mm is the focal length of choice for portraiture, but of course, it is not the only reasonable choice. A lot of photographers prefer longer focal lengths, as the additional compression tends to flatten the features a bit more, and there are some beautiful 135mm options out there at rather affordable prices compared to premium 85mm lenses, such as the Canon 135mm f/2L. There are some downsides, on the other hand. Most notable is the increased working distance. If you are working outdoors, this probably will not be an issue, but if you are shooting in a studio, things can get a little tight compared to shorter focal lengths. Still, you might prefer the look of the longer focal length for your work. Check out the video above for the full rundown from Trotti.