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It seems there are perhaps as many roads to Rome as there are 50mm lenses and their approximate equivalents – these are just some of the examples I’ve owned and/or used in the last five years, and is by no means extensive. Off the top of my head, missing are the ubiquitous Nikon 50/1.4, which I’ve owned in three versions; the 55/1.2 pre-AI; the 50/2.8 Micro-Nikkor; the Leica 50/2 Summicron; the Hasselblad CF 4/50 FLE, the Pentax 645 55/2.8 SDM – I could find images of these lenses I’d shot previously – and we haven’t even talked about other brands or extending the envelope downwards, to say 45mm or equivalents in other formats (e.g. 25mm on M4/3, or 35mm on APSC). So why the fascination with and proliferation of lenses around this range?



Sea urchins

I believe the first reason for going fifty is almost always price: there’s nothing else that gives you the same bang for buck. For the major brands, $105 is about the lowest cost of entry I’ve seen – that’s for a new Nikon 50/1.8 D, which will even autofocus on any body with a focusing motor. Canon does one for $125 that works on any body. Nikon has a $195 version with a silent wave motor and full time AF override plus aspherical elements, too. They’re probably the cheapest second lenses you can buy for your system camera right after the kit lens; even cheaper than the ubiquitous f5.6 telephoto zooms. Coupled with the price is the easy access to a surprising amount of background blur: unfortunately, bokeh is still perceived by a large portion of the public as the holy grail of photography. A 50/1.8 on an APS-C body shot wide open will yield plenty indeed; even more with an f1.4. From the perspective of Average Joe, it’s no wonder we’ve got a winning formula. Even in this age of kit zooms, some 10% of all lenses sold are 50s – that’s huge.



Tough guy

From an engineering and optical standpoint, the 50mm lens is probably the easiest of the lot to make acceptable: it requires no fancy telecentric or retrofocal groups; it doesn’t have physically large or heavy elements, and they generally don’t require the same apochromatic correction as telephotos since the magnification is much lower. Even typical helicoid throw is modest since not a lot of movement is required to focus down to about half a meter or so. You can make a decent ‘slow 50’ with as few as three or four elements; most of the modern ‘fast’ 50s are double-Gauss designs or derivatives thereof, with a 7/6 or 6/5 design. Most 50s – even the 1.4s – do not have aspherical elements, either. Even more of them use plastic or moulded hybrid elements to keep costs down further. From a manufacturer’s standpoint, they are cheap and profitable to make – plus they don’t require particularly tight tolerances or quality control.



Before work

Or do they?

A really excellent ~50 is no easier to make than a lens of any other focal length. Apochromatic correction and aspherical elements are still required for high cross-frame performance and especially at large apertures. 50mm is wide enough that you still run into coma issues at the edges – the Nikon 58/1.2 ‘Noct’ famously had a hand-polished aspherical element to mitigate this. Modern designs for maximum performance like the Zeiss 1.4/55 Otus APO-Distagon, Leica 50/2 Summicron APO-ASPH and Leica 50/0.95 Noctilux ASPH are much more complex. The two Leicas are 8/5 designs with high refractive index, aspherical and floating elements for close distance correction; the f0.95 doesn’t even focus closer than 1m and the f2 has extremely tight tolerances that must be met to avoid flare or obvious astigmatism in images. Even the Sigma 50/1.4 ART uses a complex 13/8 design. The 55 Otus takes it even further with a 12/10 formula, aspherical, high refractive index and floating elements, near focusing to 0.5m, and telecentric/ retrofocal construction based off a wide angle lens formula instead of a modified double-Gauss for better edge performance. Does it show? Yes. Are you always going to see the difference? Honestly, no. Whether the diminishing returns game is worth playing* is something only you can answer personally.

*Nikon 50/1.8D, $105. Nikon 50/1.8G, $196. Nikon 50/1.4G, $397. Sigma 50/1.4 ART, $950. Nikon 58/1.4G, $1,697. Zeiss 1.4/55 Otus APO-Distagon, $3,997. Leica 50/2 AA, $8,250. Leica 50/0.95 Noct ASPH, $10,745, or $11,350 if you want an even heavier chrome version. The 1.8G is quite noticeably better than the 1.8D, but the 1.4G actually has slightly weaker corners than both 1.8D and 1.8G. The Sigma Art is better again; the Nikon 58 is an anomaly; the Zeiss is marginally better than the Art especially in microcontrast and corner resolution at f1.4…you can see where this is going.

Undoubtedly there are some bragging rights involved in offering an f0.95 lens, or 200lp/mm resolving power, or zero chromatic aberration. But somehow I doubt there are sufficient photographers able to consistently extract this level of performance or sufficient numbers of connoisseurs able to savour the different visual textures of a Tessar vs a Distagon to justify making this many flavours. A quick search for say 28mm or 135mm lenses reveals far fewer choices, for instance. I think the fascination with 50mm goes a bit deeper than pragmatism.



The dance

Many parties are guilty of perpetrating the myth that there is a ‘natural’ focal length that corresponds perhaps with the human eye or the diagonal of the format; certainly, having a common lens that is longer in FL than the diagonal of the format (and thus the mirror size, and flange distance implications) means easier lens designing. Our eyes are clearly capable of focusing on a very narrow area with some degree of concentration, or taking in a much larger scene thanks to their unique construction and the processing power of our brains. There are some limits to this, of course – my best guess is somewhere between 24 and 150mm or thereabouts.



49

50mm on a 36x24mm imaging area corresponds to a field of view of approximately 40 degrees horizontally, 27 degrees vertically and 47 degrees diagonally. Whilst these numbers in themselves tell us very little, it’s worth noting that practically, shorter focal lengths tend to start emphasising foreground objects in an increasingly noticeable way, and anything longer starts to compress things into recessed layers. I think it’s less about 50mm being ‘normal’ and more about 50mm being the crossover point between wide and telephoto.



Lake Hawea I

This is interesting: it means that like our eyes, we have the ability to capture a scene with the impression of a wide field of view or a narrow one. Depending on both how we arrange elements spatially within the two dimensional projection onto the image (composition) and the physical distance of the original subjects, a frame shot with a 50mm lens – or rather a 47deg-ish diagonal angle of view – can appear to us as though shot with a wide and a prominent foreground (subject close to camera, background very distant) or a tele and a recessed one (subject and background relatively close, both further from camera). Clearly, this makes such a lens a very flexible tool from a compositional standpoint. If I could only have one focal length, I’d be torn between 28 and 50mm – and the latter would probably win because you can always stitch to go wider. Cropping, on the other hand, just lands up throwing away image quality.



Look out

Unfortunately, it also makes it a very difficult lens to use and an even harder one to master: if you don’t consciously decide on a strong foreground or a layered/compressed background at the time of capture, you’re likely to find there’s nothing particularly standout about the resulting compositions at all; worse still, too much bokeh and you might as well have shot your subjects in front of a fixed backdrop. A good tip to remember is that if your subject is close, then stop down – it will force you to treat it like a wide angle lens and search for elements of relevant context with which to fill the background; if you’re shooting wide open or with a distant subject, treat it as a telephoto and start looking for layers. For a very long time, 50mm (135) was a focal length and FOV I couldn’t really get my head around – it was neither fish nor fowl, not really long and not really wide. It did’t follow the rules, and that confused me. I owned many 50mms – including yes, my first non-kit lens, a 50/1.8D which I enjoyed greatly as a short tele on my APS-C D70, and two 50/1.4Gs, neither of which I liked much**. It took a lot of practice and analysis in the form of a year of shooting various 50s on an M9 and then the 55 Otus before figuring out what I was missing.

**I know I am often quoted as saying I dislike the 35mm FOV – this is not for the same reasons as 50mm; it definitely renders as a wide, but it isn’t quite wide enough for me. Practice or good glass is not going to change that – I’ve had plenty of both already. 28mm all the way…

I don’t want to open the format discussion here, but I will end by saying that all of the images in this post were shot with true 50mm (or close to it) focal lengths; however, they weren’t all on the same format. That is another discussion for another day – but pretty versatile, isn’t it? MT

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