Finding the Perfect Portrait Lens For Your DSLR

I'm a portrait photographer. So I get asked a lotnarrower the angle of view. For example, a
about what cameras and lenses the portrait28-200mm lens has an angle of view of about 74
photographer should be using. And while I'm a truedegrees to about 12 degrees. Naturally, the longer
believer that any lens can be a portrait lens, whatthe lens, the less is included in the image, and the
we're looking at here is trying to find the 'ideal'easier it is to isolate your subject on a
lens that should be the first one you reach forbackground and crop out distracting elements. Is
when doing portrait work. So what we'll examinethis all starting to seem quite logical? Good, let's
here is the 'why' behind the lens of choice for thelook at some other factors.
majority of portrait work. This is a lens that will2: LENS SPEED. In studio portraits, lens speed is
routinely work in a variety of situations andusually not that critical, since you may be shooting
produce outstanding results. Let's get starting withat f/5.6 or smaller. Outside, on location, and for
some of the key features to look for in yourweddings, you want the fastest lens you can get.
choice.No matter what your shooting aperture, it's
1: FOCAL LENGTH. This is always step one. Aalways nice to have it as bright as possible so
good starting point is to take the diagonalboth your eyes and the camera can focus better.
measure of the film or sensor your camera uses3: ZOOM LENSES. It used to be that prime focal
and multiply it by two. For example, the filmlength lenses were much better than zoom lenses
diagonal of a medium format square camera isbecause they don't have to make the many
about 80mm. The diagonal of the film is used tocompromises needed in the design of a zoom.
determine the focal length of a 'normal' lens. IWhile that's still true, lens technology is now so
believe the reasoning is that a lens of that lengthadvanced that the gap is very tiny. So in practical
gives us a 'normal' perspective when made to 8 xterms, a quality zoom will fit the bill for most
10 and viewed at arms length, but don't quotephotographers. A zoom offers many focal lengths
me. In the above instance, a typical lens length forand allows you to crop the image in camera so
portraits is 160mm. And it seems that all makersthat you can maintain optimum image quality. One
of square format lenses just happen to make aother note, if at all possible, try to buy a lens that
150mm lens that all portrait photographers own.is a continuous f/stop as opposed to those that
Translating that to the 35mm format, we'd comevary with focal length, it will make your life easier
up with a 100mm lens, and it also seems that forand your exposures more accurate when
years 35mm camera makers have made amanually metering.
105mm lens. Coincidence? I don't think so.3: OTHER FACTORS. Here are a couple of other
Now you can see that if we look at the 'perfectfactors to consider in your search for the perfect
lens' for digital, our sensor size must be taken intolens. Based on my limited testing, if you're digital,
consideration. If it's a full frame camera, then webuy the lenses made for digital cameras. Film and
can use the same thinking that applies to thesensors do not focus the same way, I see a
35mm format. If the sensor is only half the sizeconsiderable difference using digital lenses. Another
or less, that must be taken into consideration. Forconsideration is the blade shape of the lens
example, the Nikon D 80 camera chip is aboutdiaphragm. Some are designed to make more of
two thirds the size of a 35mm frame, so the lensa circle, so your out of focus highlights assume a
'conversion factor' compared to 35mm is 1.5. Thatpleasing, circular shape. Also, a Vibration Reduction
means that a 100 mm lens on a 35mm cameralens will cost you more but also allow you to
becomes a 150mm lens on a camera with a 1.5shoot handheld about two stops more than the
conversion factor. Now that I've taken the timestandard issue. If you do mostly outdoor and
to explain the relationship between film or sensorlocation portraits, I'd suggest it.
size and focal length, let's just stick with 35mm4: THE PERFECT LENS. Taking all of the above
format and you can do your own interpolatinginto consideration, I'll take a couple of stabs at the
later depending upon what camera you own.'perfect' lens. For 35mm and full frame digital,
Now that that's out of the way, what's thethere are 70-200mm f/2.8 lenses with VR that
reasoning behind the longer than normal focalseem pretty close to perfection. There are also
length for typical portraits? There are actually a55-200mm digital lenses that have variable
few reasons for it. First, there is perspective. Theapertures, pick them if cost is an issue. A shorter
perspective you have in a photo is dependentand lighter lens, like a 28-75 or 80mm, is nice to
upon how close you are to the subject, not thehave when you are working in tight quarters or
lens. Take a few images on a tripod of the samewhen the weight of the longer lenses becomes an
subject and keep changing the focal length. Whileissue. On my wish list for the future? A 50 to
some images will have more in them than others,300mm VR f/2 lens that you can throw in your
the perspective remains the same. However, topocket and buy for $400. Read this three years
include the same subject at the same size meansfrom now and you probably won't thing it's so
moving the camera. Walk up to a friend, get tworidiculous!
inches from his nose, close one eye, and look.SHOOTING F/STOPS. While the lens you use has
You're seeing what a wide angle sees in close.f/stops from about f/2.8 to f/22, for portraiture
Back off six feet and look through a paper towelyou'll probably settle on a couple of favorites.
tube, there's your long lens. So a longer thanSince not all of you have studios, let's look at how
normal lens allows us to keep some distanceyou'll be shooting outdoors.
between ourselves and our subjects, giving us aMy zoom lens goes to f/2.8 but most of my
pleasing perspective. And by keeping thatshooting is done between f/2.8 and f/5.6. I find
distance, our subject is also more comfortablethat these apertures will in most instances give
than if we shove a camera up his nostrils, so theme the 'look' I want. They are open enough to
longer length now accomplishes two objectives -throw backgrounds out of focus, but small enough
a pleasing perspective and subject comfort.to keep my subject in focus.
Now we're going to throw in another nice featureDo your own practice shooting to find your
- angle of view. The longer the focal length, thefavorites!