Why do I want a portrait lens?

My old AF 85mm f/1.8 Nikkor sits next to my bigger, far newer AF-S Nikkor 85mm f/1.8G. I loved the old lens, but I just wore it out.

I am currently in the middle of my Digital Photography for Beginners class at Pontotoc Technology Center. Monday night was lens night, during which I show and tell about all the lenses I might use for my personal and professional imaging. One lens I show is my 85mm f/1.8, regarded by many of us as an excellent, and classic, portrait lens.

I love lenses. I’m a lens guy.

Recently surfing through social media where I am friends with a huge number of photographers around the world, one of them posted, “Favorite lens? Go!”

Of course, there were tons of different replies, but the most common was simply the number 1.4. As many of you know, in photography, we label lenses by their focal length and their maximum aperture, so all these photographers were telling me they loved their lenses with f/1.4 maximum apertures. I can’t disagree with that. F/1.4 lenses are among my favorites as well.

F/1.4 is one of the largest apertures that can be engineered. It lets lots of light pass through our lens and is capable of creating a very shallow depth of field. Using this effect is called selective focus, though webizens are fond of incorrectly referring to it as “bokeh.”

So, Richard, why don’t all lenses have a maximum aperture of f/1.4? Simply put, it’s an economy of scale. Aperture is the focal length, usually described in millimeters, divided by the diameter of the aperture. A 50mm lens with a 25mm aperture is f/2.0... 50 divided by 25. To make a 200mm lens f/1.4, if you do the math, the diameter of the lens would have to be about 143mm, or nearly six inches. That’s a huge amount of optical glass, which is heavy and very expensive.

In the midst of talking about lenses, and how valuable these large-aperture lenses can be for portraiture in my class Monday night, one of my students asked me, “What about the portrait mode in my smartphone?”

It’s a great question. While it’s true that smartphones are a tool in the toolbox of portraiture, they still can’t match the versatility and image quality of a real portrait lens. For me, the biggest drawbacks to the smartphone’s portrait mode are that it can be finicky about finding focus and locking on, and it marries you to a limited number of “looks.”

While there isn’t just one “portrait” lens, my favorite portrait lens is the 85mm. I’ve owned three of them over the years, and they were all amazing image makers. I would never hesitate to recommend one. The current 85mm in my bag is the AF-S Nikkor 85mm f/1.8G, which is lighter, smaller and more affordable than the f/1.4 in Nikon’s lineup. I love that lens to pieces, for everything from portraits of our Chihuahuas to basketball action.

Late last year a photographer friend of mine visited from Tulsa, and I handed him a camera with the 85mm on it to make some images of my wife, Abby, and me. I couldn’t have been happier with the result.