50mm Lens Quiz – Test Your Knowledge of the Nifty Fifty

"Nifty fifty" is a nickname for the inexpensive 50mm f/1.8 lens. It is small and light yet delivers sharp images and a wide aperture for very little money compared to most lenses. The name has nothing to do with weight, element count, or the year it was invented.

On a full-frame camera a 50mm lens gives a field of view and perspective that look close to what the human eye sees when focusing attention on a scene. That is why it is called a normal lens. It is not wide like a 24mm or narrow like a telephoto.

An APS-C sensor is smaller than full frame, so it records only the center of the image a lens projects. Multiply the focal length by the crop factor to get the equivalent field of view: 50mm times 1.5 equals 75mm. The lens itself is still 50mm; only the framing matches a 75mm lens on full frame.

A 50mm f/1.8 uses a simple optical design with relatively few glass elements. That design is easy to make well and is produced in large numbers, which keeps costs low. The savings come from simplicity and volume, not from using plastic in place of glass.

Each full stop doubles the light. From f/5.6 to f/4 to f/2.8 to f/2 is three stops, and f/1.8 is a little brighter still, so the 50mm gathers about eight times as much light as a kit zoom at f/5.6. That allows a faster shutter or lower ISO in dim light.

A wide aperture of f/1.8 makes depth of field shallow, so the background falls well out of focus. At portrait distances that blur is smooth and soft, separating the subject from its surroundings. Smaller apertures like f/8 keep far more of the background sharp.

A fixed focal length cannot zoom, so every change in subject size requires the photographer to move physically. Walking toward or away from a subject to adjust framing builds a physical understanding of how proximity, angle, and distance affect the image in ways that zooming does not.

To keep costs down, budget 50mm f/1.8 lenses often use plastic barrels and simpler focus motors. They focus more slowly and sometimes more noisily than premium lenses, though the image quality is still very good. They focus normally and work on mirrorless bodies, natively or with the right adapter.

On full frame, a 50mm lens shows a natural, normal view without wide-angle stretching or telephoto distance. That suits street photography and portraits that include some of the person's surroundings. Birds and deep-sky objects need far longer focal lengths, and insect macro needs a dedicated macro lens.

f/1.4 is two thirds of a stop wider than f/1.8, so it lets in about 1.6 times as much light and gives a slightly shallower depth of field. Both are 50mm, so the field of view is the same. The f/1.4 is not automatically sharper; many f/1.8 versions are just as sharp once stopped down.