The 50mm prime lens is as old as 35mm film photography. Starting in the 1930’s it was the most commonly available and widely used camera lens. If you purchased a film SLR camera (35mm interchangeable lens film camera) from any manufacturer, its stock (or kit) lens was a 50mm prime. Much of the best photography of the Twentieth Century was shot with a 50mm lens. Famed photographer Henri Cartier-Bresson shot all of his work with just a 50mm lens on a Leica camera body.
The 50mm prime lens is an optically simple and highly refined design. It is cheap to manufacture and has excellent optical characteristics and sharpness. In terms of sharpness and image quality, the typical 30-year-old 50mm lens can outperform most if not all modern consumer-level zoom camera lenses. Plus, they are widely available for well under $50 on the used camera market.
I recently purchased a used SMC Pentax 50mm F:2.0 lens for $20 online to use with my Pentax K-x (12.4 megapixels) DSLR camera ( a sample image from this combo is shown at the top of this page). Pentax is a legend in lens manufacturing, creating some of the best consumer-level prime lenses ever made for film cameras. The Pentax 50mm F:2.0 lens was the entry level lens on Pentax film cameras in the 1970’s to 1980’s. Nevertheless, it is a lightweight, well-made lens capable of producing excellent images.
Why should a frugal photographer buy a used 50mm prime lens? Simple. They offer professional image quality and are dirt cheap. Their sharpness and overall image quality are only matched by modern lenses that retail for well over $500. They are faster (gather more light at wider apertures) than most consumer-level zoom lenses, making them excellent for low-light photography. They are small and lightweight. You ‘zoom’ by walking closer or farther away from your subject.
The most common lens mount for vintage used prime lenses is Pentax M42 (screw mount) and Pentax bayonet (k-mount). You can usually find an adapter to fit these lenses to modern Canon, Nikon and Sony cameras for about $10 on eBay. These are manual lenses so you have to set aperture and focusing.
The benefits of 50mm prime lenses are instantly apparent when you look at an image at 100% size or in a printed enlargement. Small details are sharper, textures are more accurately captured. Because prime lenses use fewer lens elements than zoom lenses, light is captured with less distortion. It is something you need to shoot and see for yourself!
Because these lenses are so cheap, for a little more than a dinner at McDonald’s you can own one of the sharpest, most capable lenses ever produced for modern cameras. If you plan to buy a used M42 or K-mount 50mm lens, look for Pentax, Chinon, Sears, or Ricoh brands. They all used the Pentax lens mount and sold high-quality 50mm prime lenses. Sometimes, you will find an old used film camera with a 50mm prime lens attached at a lower price than the lens alone! This is one of the best photographic purchases a frugal photographer can make!
There are some things to consider. First, vintage prime lenses make you work harder to get a shot because they are fully manual. There is a bit of a learning curve to learning to use a prime lens efficiently. You must pay more attention to your focusing and metering skills with vintage manual lenses. For shooting snapshots that will only be viewed online or in 4×6 or smaller prints stick to a fully automatic modern zoom lens. A standard ‘kit’ lens is better suited for that. However, if you want to create more artistic photos, you will find much to like in vintage prime lenses. They demand more of you but reward you with better quality and sharpness than any current low-priced zoom lens can offer. The more you ‘pixel-peep’ or enlarge your images the more amazed you will be at the quality these old lenses can deliver.