It has often been cited that 50mm lenses, when used on both film and digital 35mm SLRs is a ‘standard’ focal length. Anything longer than this is telephoto and anything wider is wide angle. The reason for this is that the perspective of a 50mm lens is similar to that of the human eye. Whilst our field of view is wider, the area in which we focus is similar to if you had a 50mm lens and subjects are rendered with a natural perspective. This makes the humble 50mm an extremely versatile and useful all-round lens.
For many years police and forensic photographers only used a 50mm lens unless there was really no option of recording the scene without using a wider lens, a small interior for example. This is because no elements of the scene would be accentuated or distorted by use of a wider focal length.
Some of the most respected documentary photographers such a Henri Cartier-Bresson would use a 50mm lens almost exclusively. The natural rendering of a scene meant that there would be no distraction from the subject being photographed.
For as long as DSLRs and rangefinders have been sold the most commonly bought lens was a 50mm. It was the kit lens of its day which began to be replaced by zoom lenses covering a 28-80mm or similar range in the last 20 years or so. The convenience of these lenses made them popular with beginners and enthusiasts who now had one lens to cover wide angle, standard and portrait focal lengths. Unfortunately these lenses are larger, heavier, slower and poorer quality.
So, why should every photographer own a 50mm lens? Well quite simply because there is not a better value lens out there. Let’s look at the benefits of a 50mm prime lens.
Compared to the standard kit lenses, and even many professional level zooms, the image quality is superior with standard 50mm lenses. By not having complex zooming mechanisms the optics can be designed with fewer compromises resulting in lower distortion and higher sharpness and contrast.
The kit zoom lenses today have maximum apertures of around f/3.5-5.6 and a professional zoom lens may have a max aperture of f/2.8 whereas a standard 50mm lens will typically be either f/1.8 or f/1.4 and can even be f/1.2 or faster. The benefits of a wider aperture are twofold: you can achieve a more shallow depth and the lens captures much more light. A shallow depth of field is a very useful tool for photographers. You can isolate a subject from the background to focus attention and remove distracting background elements. This is especially true for portraits or advertising work where you want to have the product prominent and in focus within a scene but don’t want the viewer’s eye to be drawn away. A wide aperture also allows more light to pass through to the camera . An aperture of f/1.4 lets in 4 times more light than even a professional f/2.8 zoom because it is 2 ‘stops’ faster. If you’re shooting fast moving subjects or working in low light situations then this can be crucial. If you’re with the family in a restaurant or shooting a theatre performance then it’s often not feasible to have a flashgun firing. With an f/2.8 lens you may achieve a shutter speed of 1/20th of a second which is not going to freeze subject movement. A lens shot at f/1.4 will give you a shutter speed of 1/80th of a second which can be the difference between getting a sharp or a blurry image.
I’ve listed the various options available below which as you can see there are many. For Canon, Nikon and Sony there are the great value 50mm f/1.8 lenses, as well as the f/1.4 versions. If you are going to get a lot of use then you may appreciate the slightly better performance of the f/1.4 and the higher build quality. If you are thinking about experimenting with prime lenses for the first time then the f/1.8 versions are almost too cheap to say no to.
Things become a little different if you use any of these lenses on a DSLR with anything smaller than a ‘Full Frame’ sensor such as the Canon 5DII or Nikon D700 sport. Many DSLRs have sensors smaller than 35mm film and as a result the field of view recorded from a 50mm lens is narrower and gives the impression of using a longer focal length. For example, the Nikon d300 has a sensor 1.5 times smaller than a D700. If you put a 50mm lens on a D300 it would give the same field of view as a 75mm lens on a D700. This takes away all the benefits of having a ‘normal’ lens although it can mean that the lens is even better suited to portraiture. With the four thirds system and micro 4/3rds system of Olympus and Panasonic the magnification is 2X so a 50mm lens would appear like a 100m on a 35mm camera . As a result of this there are new lenses available now that are designed to replicate the ‘normal’ perspective on these camera s.
By Park Cameras on 09/03/2018