There are very few “musts” in this world but for me the must have lens is the 55mm (50mm) or the “normal” lens for my full frame Sony a7R II or a7S II cameras.
For many reasons — which include size, weight, speed and perspective — all make this the one lens I would want if I had to choose just one.
(If you are shooting with a camera that is an APS-C sized sensor, then I would revise that to be the 35mm focal length —which loosely translates to the “normal” focal length on that size sensor. For the purposes of this note when I refer to the 50, I’m referring to the normal lens).
This is a deceptively simple lens — often called the “nifty fifty” because it does so much and can be really inexpensive (the 50mm f1.8 for Sony, Canon and Nikon all have offerings that are in what I would classify as the very inexpensive range (around $300).
Back in the 70s and 80s the 50mm lens was the "kit lens" that has been replaced by the ubiquitous kit zoom lens (16-50, 18-55, etc.) over the past 15 years or so.
The Sony 55 f1.8 is a bit pricer because it is more robust and is badged with the Zeiss brand making it one of the most unique lenses that I have used in this range. Zeiss out of focus elements have a certain look that I’ve never seen in any other brand. I have a 50mm f1.4 manual focus lens in Canon EF mount that I now use on my Sony cameras with a Fotodiox adaptor and again those out of focus elements are a thing of beauty to me with these particular Zeiss branded lenses).
More expensive and faster aperture lenses like the 50mm f1.2L from Canon push the price up but do offer a faster aperture and thus ability to keep ISO down and also get a more out of focus look at maximum aperture.
This lens is also usually quite lightweight (unless you opt for the f1.2L in Canon — but the 1.8 versions of all the big three brands are quite lightweight). The 55 1.8 Sony is heavier but is still significantly smaller and lighter than the 50 1.2L in Canon.
Having that fast aperture lens gives you a distinctive look — there’s even a dramatic difference from f2.8 to f1.8. The other day I was testing a new 50mm lens with a friend and we were amazed at just how much difference in sharpness and definition in the background elements there were from f4 to f1.5 (the maximum aperture for this lens— the Voightlander Nokton 50mm f1.5. This is a Leica M mount lens that can be adapted for Sony E mount cameras using, in his case, the Voightlander Close Focus adaptor).
But the real beauty in the focal length is perspective. All the techie things are cool but what the lens really gives you is the look. The 50/55 just gives you a perspective, especially when coupled with the large maximum aperture that can really draw in a viewer by how you place your subject in the frame and what you decide to include.
Stand back quite far from your subjects and they become an element in the landscape but aren’t so small that you can’t see them (as might be the case with wide angle lenses).
Move in close and you can get some interesting portraits (especially for more environmental type portraits) — interesting because they still allow for a bit of context in the background. Even at a large aperture there can often be enough tell-tale signs of where and what the background is but, because of the large aperture, doesn’t distract or detract from the subjects.
If you photograph the same scene with a short telephoto lens like the 85mm on a full frame sensor camera, those background elements are further softened and any context is taken away because of the narrower angle of view.
The 50 was a lens that I originally didn’t use. I thought it too ordinary. But when you look at all the great work shot over the decades with that normal lens by greats such as Henri Cartier-Bresson among others, you begin to respect the power of this focal length.
When coupled with vision and skill and a commitment to make that lens work, the images that you can produce from it are magical.
So how about you? What lens would be YOUR one lens?