Currently, there is an advertisement being shown on television with the goal of convincing new camera owners to purchase more another lens for their new DSLR camera. The ad begins with a picture of little girl in a playground. Viewers see the child in the foreground with lots of stuff behind her. Then as viewers are told to purchase a better lens the picture changes to a sharp portrait of the child with a soft out-of-focus background. The subject much remains the same, but, because the clutter in the background is diminished, now the portrait is more pleasing.
Viewers are given the impression that there is a special type of lens made specifically for portrait photography and to buy it if we want good portraits. I agree that buying the best quality lenses will give photographers the highest quality image, however, the difference between the two pictures viewers are shown doesn’t really have anything to do with good quality lenses. Any photographer can easily create the effect of a blurry background by using the same lens (or any lens) by choosing a wider aperture to reduce the depth of field.
Depth of field is defined as the area around the main subject, in front of, and behind, that is in acceptably sharp focus. The smaller the aperture the greater the field of focus is, and the larger the aperture the less the field of focus, thus by focusing on the subject and reducing the field of focus, much of the area in front of, and behind, the subject looses sharpness.
In my opinion learning to use a camera effectively is more important than falling for the hype put forward in ads like that. All photographers should learn about depth of field, composition, and metering. They should have an understanding of perspective, and why at times subjects in the foreground seem uncomfortably larger than those standing only a few feet behind. Fast action is easily controlled by increasing the shutterspeed, and if the elements in the picture aren’t bright enough, by increasing the camera’s ISO. Sharpening the landscape on a bright sunny day only takes the additions of a lens hood to reduce lens flare; and, as always, in my opinion, the best scenics are those where the photographer uses a good sturdy tripod.
I advise saving some money and purchasing a book on portraiture, or, at least basic photography instead, and there are lots of online forums where photographers show, discuss, and exchange advice on their pictures. Or, readers could take a class.
The voice in the advertisement advises that photographers can change from a good shot to an amazing shot if a better lens was purchased. I regularly talk to photographers that believe the only way to make better pictures is to buy a new camera, and I expect because of that advertisement they will go out and purchase new lenses in the misguided belief that they will suddenly become better at photography.
What I actually like about the ad, in spite of the not so truthful claim that a good portrait is only accomplished when one buys another lens, is that it gets photographers thinking about adding to their collection of lenses. All camera manufacturers (just like auto manufacturers) have various levels of quality and one type of lens isn’t necessarily the best for all subjects. As long as I have been involved with photography the catch phrase “it’s all in the glass” has been around. And I regularly tell those new to photography that they should be changing lenses before changing cameras. Nevertheless, I also tell them that they should know what they expect from a lens before purchasing it; and after researching it to match their expectations with what they can afford to acquire. There isn’t necessarily any lens that might be called a portrait lens and the selection of which lens to use is really up to the photographer. I think an in depth discussion of lenses is best left to another time.