Lens Selection

For "normal" portraits perspective is a very critical part of any equation. In other words does the portrait actually look like the person being photographed? If the final result meets or exceeds that goal then the lens might be considered a good portrait lens.

Most people will say that the focal length of the lens determines the perspective. While I mostly agree i often shoot with lens that are not portrait lens. If you compare rectilinear lenses (i.e. not super wide angle), you will find that the perspective is determined by your distance from the subject and the relationship of the film plain to the subject. The subject size is determined by the focal length.

Think of it this way. If you are 100ft from a horse and you photograph it with a 20mm lens and a 200mm lens, the horse will be 10 times larger with the telephoto lens. However, of you enlarge the image taken with the 20mm lens 10 times it would show exactly the same perspective as the shot taken with the telephoto lens. However, the images will not be equal. The image noise would be much more noticeable and it would look less sharp. However, the perspective view of the deer and the background would be the same.

This is important because we normally look at people when they are a normal distance away from us. Let's say say around 6-9 feet. When we chose a lens we are looking for a lens which will give us a reasonable "head and shoulders" portrait when we're a normal viewing distance from the subject.

If you are shooting with a full frame DSLR like the Canon 5D then a normal portrait lens would be around 100mm. The "classic" range for portrait lenses on full frame 35mm format cameras is from around 80mm to 135mm. For smaller sensor size cameras the focal length range would be around 50mm to around 85mm.

The reason that we don't want to shoot with a super wide angle lens is that magnification is a function of distance. If your subjects nose is 1/2 the distance from the lens than the ears, the nose will look proportionately twice as big as the ears. If you must shoot a portrait with a wide angle lens you will want to back off so that the difference in magnification will be smaller.

As discussed elsewhere, another characteristic of portraits that drives your lens choice is the speed of the lens. A faster lens will allow you to have a more open aperture and thus blur the background. The blurring of the background is controlled by two factors. First being the aperture and the second being the focal length of the lens. (See Depth of Field)

Most current DLSRs are APS-C format. As mentioned above these cameras have a smaller sensor and as a result the focal length requirements for portrait work are modified. This is because at a given distance from the subject you can fill the frame using a shorter focal length. For a camera with a APS-C DSLR the "multiplier factor" is 1.6x, so a 50mm lens will give you the same results as a (50 x 1.6 =) 80mm lens would on a full frame camera.

Recommended Portrait Lenses

So, what are the best portrait lenses? If you do not have a full frame camera you can start out at 50mm. This is an excellent focal length for portraits for these cameras. With an appropriate subject distance they can make acceptable lens for full frame cameras too.

While you can certainly shoot portraits with shorter focal length lens, the "normal" perspective starts at around 50mm for "head and shoulders shots". For full length you can get acceptable results with a lens like the 35/2.0.

• Canon EF 50/1.8 II - This is a good deal. It's fast, small, light and cheap.
• Canon EF 50/1.4 USM - A better built lens with a faster aperture for increased background blur.
• Canon EF-S 60/2.8 macro - An EF-S lens which means it ONLY fits on APS-C DSLRs like the Canon 10-50D series. It's a good dual purpose lens.
• Canon EF 70-200/2.8L IS or Non-IS These are very sharp, fast zoom that covers the whole "portrait lens" range. The "IS" version makes working without a tripod easier, but that lens is very heavy. I personally use the smaller version.
• Canon EF 85/1.8 USM - This is an excellent range for both APS-C and full frame DSLRs. It is very sharp, fast, and is an ideal focal length for full frame portrait work. For my 40D I prefer the 50mm over this lens.

My Portrait Lens Picks

From the list above I use the 50mm and the 70-210 almost exclusively. If you are tight on money, purchase the 50mm lens for a APS-C style camera and the 85mm for a full frame camera.