With only a two-and-a-half-year market life (Spring 1983 - Winter 1985), it might seem that the Zoom-Nikkor 50-135/3.5 AI-s was a failure (just over 31,000 produced) for Nikon. Adding to this perception is the fact that it never made the transition to auto focus (AF), as did its pseudo-successor, the much longer-lived AI-s 35-135/3.5-4.5 (almost 92,000 produced from 1984 - 98 in MF and over 282,000 produced from 1986 - 98 in AF form). But when we dig a little deeper, a fascinating (for a lens geek, anyways ;-)) tale emerges. What were the real reasons for the 50-135's untimely demise? Here is the story of a sleeper Nikkor lens...one that still performs surprisingly well in the current digital age.
The Best of Times...and the Worst of Times
The Zoom Nikkor 50-135 was born in turbulent times, being conceived and designed right at the height of the biggest 35mm SLR sales extravaganza up to that point and then going into production right as the bottom was falling out in 1982. Zoom lens development was hot and heavy in the early-1980s. Advances made in computer processing power in the late-'70s spurred the development of more sophisticated software, thereby allowing lens designers to, not just entertain the idea of more ambitious and complex zoom lens formulas, but actually bring them to fruition. The 50-135 was a direct beneficiary (and would become, ironically, a victim in short order) of such progress. It served as an exploration by Nikon into an optical layout they were hitherto unfamiliar with, and would ultimately end up abandoning. The confluence of these factors, along with the AF revolution, conspired to make the 50-135's lifespan a short one. But that also added to the uniqueness of the whole experience, sort of like this for Tom Petty fans:
Design work for what would become the 50-135/3.5 AI-s began in the Spring of 1980, by Kiyoshi Hayashi, one of Nikon's optical design stars, who had cut his teeth on no less than the AI Nikkor 200mm f/2 lens (still an amazing lens) and other high-performance AI Nikkor telephoto optics in the late-'70s. The fact that Hayashi-san was basically given free rein to explore the "yamaji"-style optical layout that would be used for the 50-135 indicates the esteem he was held in by his superiors. His appointment to this assignment also gives an indication of the importance in Nikon's eyes of the development of such lenses at that time: this was a priority, not just an intellectual exercise. Now, Nikon had been at the forefront of Japanese zoom development for two decades prior to this, evidenced by the sales success of their 43-86/3.5, 80-200/4.5, and most recently, the first true wide-angle zooms (the 28-45/4.5 and its successor the 25-50/4). But they did not have a monopoly on lens design ;-). Keizo Yamaji was the name of an optical designer from Canon (Gasp!). And he had developed a unique four-group layout for zoom lenses back in the late-1950s & early-'60s (convex/concave/concave/convex). When talking "groups" here, we are referring not to groups of individual lens elements, per se, but the basic optical sections of a zoom lens and their overall shape (convex/concave or positive/negative). In the case of the 4-group zooms we will be considering in this article:
Nikon's favored telephoto zoom four-group layout prior to the development of the 50 -135/3.5 was convex/concave/convex/convex. This was Nikon's first (and only, as it turned out) foray into the intricacies of the Yamaji design (Canon's patents having expired by the end of January 1980). One of their major hopes was for a reduction in the size and weight in this class of lenses. Did such hopes come to pass?
The Short, Somewhat Happy Life of the Nikkor 50-135/3.5 AI-s
In a word...no. With a weight of 700 grams (24.7 oz), a length of 125mm (just under 5"), and a diameter of 71mm (2.8"), the 50-135 is not an unsubstantial piece of kit today in a world where 70-300/4.5-5.6 lenses come in at about the same size, but 200 grams (7 oz) lighter (thank you, polycarbonate ;-)). But even in its day, the Nikkor was underwhelming when it came to weight-savings over its peers. Some of this had to do with Nikon's pro-level material and construction choices, but it was also a result of their coming up against the compromises of the Yamaji layout. One of the advantages of the Yamaji design was that it allowed for less space between the variator and compensator groups, thus allowing the lens to be shorter overall. However, because both groups were concave, the light rays were bent more than normal and so required a larger, more complex master group to correct for that, which negated the dimensional gains the variator/compensator groups had made. Half of the 16 total lens elements are used in the master group alone.
Another fly in Nikon's ointment was the unfavorable weight comparison to the common 75-150/3.5 or 4 (or thereabouts) zooms with their more consumer-friendly prices and weights in the 450 - 550 gram range. But the biggest problem for all of the 50-135s was the rapid development of 35-135/3.5-4.5 lenses that hit the spot for many photographers in the mid-'80s as far as versatility, price, and weight was concerned. The succeeding 35-135/3.5-4.5 Nikkor AI-s was 14% lighter and 17% more compact while adding an extra 15mm of focal length on the wide end (but at the expense of the constant aperture of the 50-135). In truth, the 50-135s were really transitional optics on the way to higher zoom ratios. So it was not just the Nikkor that fell by the wayside as the march of "progress" continued. As noted earlier, the 35-135 Nikkor successfully transitioned to AF in 1986, was redesigned in 1988, and survived until 1998, a more-typical lifespan for a Nikkor lens. So it was really a combination of the rapid advance of zoom development and a shift towards more consumer-targeted zooms that doomed the 50-135/3.5 AI-s. For its abbreviated life, the lens actually sold reasonably well.
So, What Makes the 50-135/3.5 AI-s Special?
How can a lens that failed to achieve a major design objective still be considered a success? Outright performance, that's how :-). Certainly, as far as making zoom construction more compact and lighter-weight, the 50-135 Nikkor plainly did not move the needle. But Nikon's only crack at the "yamaji" optical formula did yield some unique results, some of which are sought-after by modern lens aficionados. It is worthy of note that the very-good-to-excellent optical performance of the 50-135 was achieved without: aspherical elements, extra-low dispersion glass, movable focus groups, or any of the other technologies that have since found their way into even the cheapest kit zooms of today. It was pushing the limits of conventional lens technology at the time.
First, we need to consider what the designer intended the lens to be used for. Hayashi-san's choices as to how to balance the various aberration corrections and performance at certain focal lengths play to the strengths of the normal-to-portrait focal range of this lens. Portraits tend to be shot at closer distances, so he chose to under-correct for spherical aberration at closer focusing distances, particularly from 90mm and up. The result? Smoother out-of-focus rendering and transitions at most focal lengths at those distances. It's like he knew that the lens should be used that way, or something ;-). No, it's not a creamy-dreamy bokeh machine, but it does very nicely for my eyes, especially from 105 - 135mm. F/3.5 or 4 makes for a great portrait aperture setting.
Zooms, even modern ones, cannot maintain identical performance at all focal lengths. And this is even more noticeable with lenses of the 50-135's vintage. But, again, this lens does remarkably well at maintaining a consistent look across the focal length range. While flare wide-open does increase as you move from 50 -135mm, stopping down to f/4 or 5.6 provides uniform rendering and contrast. Best landscape performance is to be had at f/11 at all focal lengths.
While the Yamaji formula did not take still photography by storm, it did become the standard for zoom lenses used for TV and video production. And, while this feature was probably far from Hayashi's mind, a unique characteristic of the 50-135/3.5 AI-s is on the lips of hybrid-shooters and videographers of today: Focus Breathing.
What the heck is focus breathing? Very simply, it is a change in the focal length of a lens when focus changes from near to far or vice-versa (due to the internal movements of the lens groups). The modern Nikkor AF-S 70-200/2.8G ED VRII lens is often held up as an extreme example of a heavy focus breather at the 200mm focal length. At the 70mm end, when focused at infinity, the effective focal length measures 71.4mm. When focused to its minimum distance of 1.4m (4.6') the focal length changes to 66.6mm, a change of 7%, very common among lenses designed with stills photography in mind. Anything under 5% is considered negligible with stills lenses, so not a terrible performance by any means. At 200mm though, the difference becomes very apparent: at infinity we have 196mm focal length (well within normal tolerances), but at 1.4m close focus, it drops to 137.7mm, a staggering 30% decrease in focal length. That's very noticeable even for stills, and completely unacceptable for professional videographers or cinematographers. (This gives you a clue as to why Cine lenses are so much more expensive than their stills equivalents :-)) While an inconvenience (to a larger or lesser degree) for a stills shooter, excessive focus breathing will ruin many a sequence for a videographer when focus is pulled from far-to-near or vice-versa. It will either allow things to encroach on a scene (known as "negative", because you are losing focal length) or exclude them (known as "positive", because you are gaining focal length) when not desired. How does this relate to the 50-135 AI-s?
While never conceived as a cine lens or tool for even enthusiast videographers, the yamaji-type optical design of the 50-135 Nikkor has contributed to making it a viable hybrid-shooting zoom lens for some. Is there focus breathing? Absolutely. But it takes the positive form, which is less problematic, overall. At both ends of the focal length range the 50-135 gains as you focus closer (which can be usable in certain situations). As you gain focal length, breathing becomes less and less of an issue with this lens
At the 50mm end:
At the 135mm end:
With traditional Nikon zoom designs, you lose focal length as you focus closer, with the 70-200/2.8 ED VRII being the most extreme example. So it is much easier for things to creep into your frame as you focus closer. With the 50-135/3.5, you can use its focal length gaining characteristic as a little extra zoom boost if you so desire. The constant f/3.5 aperture is handy for video as well. No, I'm not saying that this lens is the cine secret of the century, but if you like to play with video a bit as well as portraits and landscapes in stills, you might find it interesting.
Is it perfect? Of course not. The barrel distortion at 50mm is high at 3.9% (but not out of the ordinary for zooms of this age) focused at infinity, which is not great, but at least we can compensate for that in editing, nowadays. By 90mm, it has switched to around 2% pincushion which grows to roughly 3.5% at the 135mm setting (again, focused at infinity). An architectural lens this is not :-). Like most older lenses, contrast increases as you stop down, which I prefer myself, but is not for everyone. If you are not used to the weight of zooms from four decades ago, the 50-135 could buckle your knees ;-). On bodies that weigh the same or a bit more (F2, F3, F90, D300, to name a few), it balances quite nicely in the hands. When shopping for one, beware of fungus or mold infestations, which are commonly found at the low end of the price-range. The complexity of the design makes for a higher degree of difficulty to CLA (clean, lube, adjust) this lens. As with the majority of one-touch zooms from this era, zoom creep is very common due to a worn-out felt ring inside the zoom/focusing ring. This can be replaced with either new felt or modern foam, if you have the patience for it (warning: some disassembly required). A thin strip (say 1.5 - 2mm wide) of 2 - 2.5mm thick self-adhesive closed-cell foam (of the type used for film seals) seems to work well.
When the Nikkor 50-135/3.5 AI-s went on sale in 1983, it was priced at $820 USD. That put it into the same price bracket as the 85/1.4 AI-s and 25-50/4 AI-s. Obviously, it was not designed to outdo either one of those lenses, but it just serves to show that this was not a budget, consumer-level lens. By the time its "successor" the 35-135/3.5-4.5 came along for $595 USD just two years later, the 50-135 was being blown out for $380 USD to make room for the newer, wider, but slower lens. The disparity in the introductory price points shows the drop in aperture specification, which was the only way to boost the zoom ratio while dropping size and weight, and also the state of the manual focus photographic gear market in 1985. Today, both sell in the same $50 - $100 USD range, which makes them both bargains in my book. But my heart is with the 50-135. Nikon didn't build it just because it would sell...they built it out of curiosity and a desire to push forward, and they didn't compromise on the optical performance to save weight and cost. I know that the optical designers of today are just as curious and ambitious as their predecessors, and the optics we are getting today are phenomenal. But how many Nikon APS-C shooters today would love to have a quality constant aperture 75-200mm full frame-equivalent f/3.5 or 4 for $800 USD. Heck, with today's technology and materials, I bet Nikon could even throw in Vibration Reduction and a 200 gram weight reduction at that price ;-). Will we ever see one? It's highly doubtful, seeing as Nikon management is adamant that APS-C is only beginner stuff, and have left it to the third-party manufacturers to fill the void. So where does that leave us?
Well, if you don't mind the weight and manual focusing, the nearly-vintage Nikkor 50-135/3.5 AI-s makes for a flexible portrait and landscape lens, a passable moderate-telephoto video optic, and its constant aperture makes it a piece of cake to program as a non-CPU lens for your modern Nikon DSLRs and mirrorless bodies that accept AI-lenses (with the FTZ adapter for mirrorless, of course). The non-rotating front filter thread is also a plus for polarizer or graduated filter fiends :-). You might also like it with other-brand mirrorless bodies with appropriate adapters. It will easily out-resolve any film you feed it and can hang in there with modern APS-C (20-24 MP) and full frame sensors up to 36 MP at f/5.6 - 11. Mine moves comfortably from film (F2, F3, F90X, and the like) to digital (D300, etc.) bodies without complaint. It is one of the most versatile lenses (for my style of shooting :-)) I own. Yep, it's the heaviest lens of its class. I guess that's why everyone needed their Wheaties back in the '80s. In the 2020s, you'll need your gluten-free equivalent. At least we celiacs do ;-).
The Thousand and One Nights #61 @ https://imaging.nikon.com/history/story/0061/
Various patents @ Google Patents
Various Issues of Popular Photography 1981-85
Sears Camera Catalog 1977-78 @ https://www.butkus.org/chinon/catalogs_photo.
About Focus Breathing @ http://www.pierretoscani.com/breathing.html#breathing11
Roland Vink's Nikkor Lens Pages @ http://www.photosynthesis.co.nz/nikon/lenses
Suffers from a two-decade and counting film and manual focus SLR addiction. Has recently expanded into 1980's AF point and shoots, and (gack!) '90s SLRs. He even mixes in some digital. Definitely a sick man.