During the last few months, a colleague from work has been doing his homework in preparation for buying a new camera kit.  Especially during the past week (as he’s getting ready for a major vacation out of the country), we’ve been spending time discussing his lens choices.  Although he is primarily interested in photographing scenery and cathedrals (and, thus, leaning toward wide-angle lenses), our discussions reminded me of the struggle I went through to select the “right” lens for doing portraiture.

 

 

            c = Sqrt(a^2 + b^2)

 

For most 35mm cameras, the in-camera image is a rectangle measuring 24mm x 36mm.  Applying Pythagoras, we get a diagonal of 43.267mm, thus a “normal” lens would be about 43mm in focal length.  Although some camera manufacturers came up with lenses having focal lengths of 40mm and 45mm, most “normal” lenses were made to a focal length of 50mm (a nice round number).  For some medium-format cameras, a “normal” lens was somewhere between 80mm and 90mm.  For large-format (like view cameras), a normal focal length is significantly larger.  Conversely, for smaller cameras, a normal focal length is significantly smaller.  The variety of in-camera image sizes increased dramatically with the introduction of digital cameras.  Even today, we have cameras that look like 35mm cameras but have either “full frame” sensors (equivalent to 35mm, such as the Canon 5D) or smaller sensors.  Canon, for instance, has had a popular line of cameras (10D, 20D, 30D (and most recently the 40D)) with a sensor that is 1.6x smaller than “full frame”; thus a 50mm lens on a 30D, would have the same telephoto effect as an 80mm on a 5D — 50mm is “normal” on the 5D and slightly telephoto on the 30D.  I’ll leave it to you to figure out what “normal” should be for your camera, and we’ll resume our discussion of portrait lens choices based on a multiplier of “normal”.

 

The image above was taken with a lens whose focal length was 1.7x normal (in my case, an 85mm f/1.8).  I love this lens for portraits that are no closer than waist-up.  The lens can certainly focus more closely when needed, but I find that moving in closer causes the proportions of the face to get exaggerated — noses and chins get longer.  Also, when I move in closer for a tighter shot, my depth-of-field (especially when shooting wide-open (f/1.8)) is not sufficient to keep the nose, eyes, and ears in focus simultaneously.  Another important consideration when moving in closer is that the person being photographed may start to feel crowded with the camera being so close.  When I want to have a tighter shot (say, “head and shoulders”), I will use a lens whose focal length is at least 2.0x normal (such as a 100mm).  To go in even tighter (a “head shot”), I’ll step up to a focal length that is closer to 2.7x normal (such as a 135mm).  These choices of focal length help preserve a comfortable working distance between the photographer and the subject, and keep the perspective distortions to a minimum.  Going more telephoto, such as 4.0x and beyond, brings you into the realm of “sniper portraiture”.  Because of your significant distance from the subject, you often get more candid photos because the subject might not realize you’re even taking a picture; such longer lenses are often used at parties and other social gatherings.  Of course, when the subject doesn’t know you’re taking their picture, they also don’t hold a pose for long, so you have to react more quickly.

 

When I go the other direction — either a “full-length” shot or a group (family) shot, I’ll drop down to the “normal” focal length (in my case, a 50mm f1.4).  I can still use a more telephoto lens than this, but doing so increases my camera-to-subject distance and that greater distance tends to allow the subject (or group) to be more easily distracted (eyes wandering off from the camera), and communication is harder (I have to shout).  I could go wider — say to 0.7x normal — for a group shot, but then I start encountering the distortions of wide-angle lenses, and I don’t care to go through the trouble of digitally warping the images on the computer to correct for these distortions.  Sometimes, especially with a large group and indoors, we seemingly don’t have a choice and feel compelled to use a wider lens; I’ll almost never drop below 0.7x normal, even when my back is against the wall (literally and figuratively) — it’s often better to change location (even if that means going outside) to be able to avoid using a wide-angle lens.  I should mention, there is another problem with using wide-angle lenses in portraiture: you get an inherent increase in the depth-of-field from wide-angle lenses, and it becomes harder to blur-out the background to eliminate distractions behind the subject.

 

There are a wide variety of zoom lenses which incorporate many of the focal lengths discussed here.  Generally, a “prime” (non-zoom) lens is going to be smaller, lighter, have a larger maximum aperture (which is important for putting the background out of focus), be less expensive, and be optically superior to a zoom.  However, when enough money is paid (such as for the coveted Canon ‘L’-series zooms), there is sufficiently high quality in these zoom lenses to make them very attractive for the portrait photographer — especially to avoid having to switch lenses during a shoot.  And, if you have a broad range of shooting needs and want primes for several different focal lengths, the high-quality (and expensive) zoom will often be more economical and convenient.

 

In this article, I’ve presented some guidelines for choices of lens focal lengths based on some different portrait situations and goals.  These guidelines have been developed over 30 years of doing portrait photography.  However, these are only guidelines.  I’ve seen some tremendous portraits taken with ultra-wide (0.28x) and fish-eye lenses on the one extreme, and strong telephoto (12.0x) lenses on the other extreme.  You should regard the guidelines presented here as a good starting point, and then experiment to find what works best for you.