Why Be Normal?

A fellow photog whom I’m try to convince to purchase a 50mm and 35mm prime lens asks, “why do I want these”. Currently, he owns a full-frame camera with two zoom lenses; standard and telephoto.

To him and others like him, I offer this...

The normal field of view of human vision equates approximately to the diagonal measurement of the film or sensor frame. In this case, that’s about 43mm. In the early days of camera manufacturing, it was easier to make a sharp 50mm lens than shorter focal lengths, so 50mm became the standard and today represents the “baseline” focal length. Back in the day, when you bought a 35mm camera with an interchangeable lens, it came bundled with a reasonably fast 50mm lens. And this lens is just about the fastest, sharpest, highest quality optic you can buy for your camera.

Since its angle of view approximates what the human eye sees (cropped by the 35mm frame of course) it’s naturally easier to capture your visualization of the subject in the frame, and to do so in low light, with lower distortion and aberration than you would get using a zoom lens. It also encourages you to “zoom” by moving towards, away from and thus around your subject. So, in this way it takes away the “restrictions” you naturally have with a zoom lens. If you can’t make a great photo with a normal lens, you won’t do any better with a zoom.

Once you get used to composing with a normal lens, you will learn good habits that will benefit you when you move on to working with a zoom. For example, photogs used to working with prime lenses will “dial-in” the focal length on a zoom first, choosing it for the perspective it will achieve, then compose by moving around the subject.

The “perspective” of the composition is far more important than its scale in the frame. So, you choose your angle of view with the focal length first, then control its scale by altering the camera-to-subject distance. Prime lenses make it much easier to do that.

So, why a 35mm wide-angle lens as a second lens?

Lenses with wider viewing angles encourage you to get closer to the subject, and thus more intimate. They put you “in the heart of the action”. If you are in a moderately-sized room, they allow you get the shot while actually being in that room, and not having to shoot through an open doorway. They also have deeper depth of field, and thus less critical focusing requirements. They are forgiving of slower shutter speeds. And although slower, usually by only one stop compared with “normal” lenses. And, being close to 43mm, they are arguably more “normal” than a 50mm. Lastly, they are the choice of many famous photographers.

Another way to think about it is that 43mm is just about dead center between 35mm and 50mm, making working with these focal lengths ideal in terms of range; slightly wider, and slightly narrower than “normal”.

So, the bottom line is, if you’re going to add prime lenses to your kit, the 50mm and 35mm are essential.