Noteworthy Lenses – Nikon Nikkor 20mm ƒ/3.5

Nikkor 20mm 3.5 18

It’s time for another examination of a noteworthy lens. Last time we looked at the Minolta Fish-Eye Rokkor-X 16mm ƒ/2.8, and again we’re checking out a wide-angle lens from the Land of the Rising Sun. It’s Nikon’s Nikkor 20mm ƒ/3.5 AI-S. Made in 1981, this thirty-something-year-old lens remains one of the best wide-angle lenses for the F mount system.

Lighter, more compact, and less expensive than modern Nikkor lenses of similar focal length, the 20mm ƒ/3.5 AI-S is a lens for which it’s easy to justify ownership. When it’s understood that the optical characteristics of this lens are equal to those same modern lenses, ownership should be a foregone conclusion. I’ve qualified the previous statement with the word “should”, because not everyone will love this lens. For some shooters the requirement that it be focused manually will be an unfortunate deal-breaker, but for those who embrace the past and eschew ultrasonic, auto-focus motors, the Nikkor 20mm ƒ/3.5 will be a real gem.

Nikkor 20mm 3.5 1

Lens from 1981 on a camera from 1959. Nikon’s F mount is certainly prolific.

Nikon’s F mount Nikkors have a long and storied history. They comprise the oldest lens range still in production, and they’ve been going strong for more than 50 years. Over this span there have naturally been some revisions. Beginning in the late 1970’s the range was revamped to allow for automatic indexing at maximum aperture. These new lenses, dubbed AI, allowed the camera to know the aperture of the lens without the lens being stopped down. Further developments in the 1980’s would allow for Nikon cameras that could automatically adjust the aperture of the lens for use in Program and Shutter-Priority modes. The lenses made for these cameras would be referred to as AI-S lenses.

There’s little to physically distinguish any given lens from a lens of a different era. Aside from a small change to aperture text colors, aperture ring shape, and a notch on the back of the lens, they all look very similar. Knowing what to look for on the lens and keeping in mind what camera the lens will mount to are important factors when deciding what type of lens to buy.

Nikkor 20mm 3.5 14

AI-S lenses can be differentiated from earlier lenses by their orange minimum aperture numbers, and a notch in the metal of the lens mount.

Buying older “non-AI” or AI lenses can lead to compatibility issues with modern machines, especially today’s DSLRs. Some very old Nikkor lenses can even damage the auto-indexing tab on modern FX and DX cameras, such as the D610. To avoid breaking a full-frame masterpiece the wisest option is to simply shop for AI-S lenses, as these are compatible with every Nikon SLR made since 1959. To determine if a lens is AI-S, look for the minimum aperture number on the aperture dial to be painted in orange, and check for a vertical notch positioned just above the lens locking notch in the metal lens mount.

But enough of all that. Let’s get to the fun stuff.

The Nikkor 20mm ƒ/3.5 AI-S has an angle of view which is 94º when shot on a 35mm film or full-frame Nikon FX camera. What this means is that the lens absorbs a lot of whatever it’s pointing toward. This ultra-wide view is excellent for congested city streets, architectural shots, interior shots where space is limited, or the vast and impressive vistas of landscape shooting. Very rarely does one worry that something will be out of frame or out of focus. This is about as close to point-and-shoot as an SLR lens gets.

Nikkor 20mm 3.5 17

The Nikkor 20mm ƒ/3.5 is great for creating dynamic shots in street photography.

Used on a crop-sensor camera such as Nikon’s DX range, the angle of view comes in around 74º, so there will naturally be less coverage. Even handicapped in this way, the lens still offers a respectably wide 30mm focal length. This difference is a product of crop-sensors, like those found in DX and mirror-less machines, and the math is simple once the concept is understood. While the shooter loses some focal length, a happy byproduct is the elimination of the mild vignetting typically encountered with wide-angle lenses- more on this later.

Whatever the size of the sensor, practical use of this lens is a real pleasure. This thing has phenomenal build quality. At 235g it’s weighty, but not heavy. Entirely metal construction in a compact form imbues the lens with a feeling of quality. The focus ring spins with clinical fluidity and is lightly weighted to allow focusing with only one finger. Rotational action is kept to a relatively short 70º so focus is extremely quick, and the inclusion of a focus-scale makes it difficult to miss a shot for lack of focus. The aperture ring clicks solidly in single-stop increments from ƒ/3.5 to ƒ/22. Filter threads are metal and use 52mm diameter filters, and the metal lens mount is typical of Nikon’s dedication to exceptional machines.

Nikkor 20mm 3.5 19

Optical qualities of the Nikkor 20mm ƒ/3.5 are about as tasty as a berry tart.

Optically the lens is outstanding, with a few caveats. Getting to the positives, color-rendition is fantastic due to Nikon’s exceptional coatings. There’s no chromatic aberration (the purply-colored fringes found in high-contrast areas of an image), and sharpness is excellent. The edges of the frame are slightly softer than the center when shot wide-open, but it’s really a negligible lack of detail only seen under extreme magnification. Stop the aperture down to ƒ/5.6 or ƒ/8 and tack-sharpness becomes uniform throughout the frame, and remarkable for its quality. Flaring and ghosting are virtually nonexistent.

If this lens has a weakness it’s in its tendency for vignetting, or light fall-off. When shot wide open the effect is pretty heavy, resulting in darkened corners creeping in from the outside of the frame. In certain situations it can lead to an interesting artistic affect, but in all honesty it’s usually undesirable. The lens in question isn’t the worst culprit, but there are certainly situations where the vignetting is just too heavy. Luckily if one stops the lens down a bit the fall-off becomes substantially mitigated. At ƒ/5.6 it’s barely visible, and at ƒ/8 and above it’s all but disappeared. Also important to remember is the ability of modern software, such as Lightroom, Aperture, and Photoshop, to easily correct unwanted vignetting.

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As with any wide-angle lens, close-up distortion and vignetting are common problems. This lens is among the best at mitigating these.

As with any wide-angle lens, distortion can be a problem in certain shooting situations. The optics are very well-corrected, but when shot too close to a subject there’s a tendency for wild distortion. This isn’t a knock on this particular lens, simply a product of the mathematics of wide-angle optics. Under normal shooting conditions the lens shows mild distortion of the wave variety in areas where parallel lines run close to the edges of the frame. It’s not extreme and can be left alone in most cases. In instances where distortion is strictly prohibited it can be sussed out in post-processing. Methods of doing this can be found elsewhere; this is Casual Photophile, not Obsessive Photophile. Rest-assured that this is one of the best-corrected wide-angle lenses out there.

Nikkor 20mm 3.5 7

An out-of-the-ordinary focal length helps the photographer see the world differently.

The 20mm focal length is one of the lesser-celebrated lengths, but this in no way diminishes its power. The images produced at this focal length can be counted among the most dramatic of all. Shoot a standard 35mm or 50mm lens for a few months and the change is drastic. Going to 20mm is an entirely different type of shooting. Shooting an ultra-wide, one starts to see the world differently. This lens brings a certain dynamism to the commonplace. It pulls subjects closer and pushes backgrounds way off into the distance. It can make motion look faster, distances look vaster, and cramped spaces less claustrophobic. It’s one of the more versatile focal lengths, and one any photographer shouldn’t live without.

For Nikon’s range, the 20mm ƒ/3.5 AI-S is one of the best deals in wide-angle shooting. Ultimate quality at an affordable price, it’s a lens that will bring a new dynamic to a number of photographic styles. Nikon street photographers, landscape artists, and architectural shooters shouldn’t be without this lens. Artistically it’s a lens that can create astounding images. Technically it’s one of Nikon’s best. Any way you look at it, it’s a noteworthy lens.

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  • Reply
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  • Reply
    Randle P. McMurphy
    January 8, 2015 at 2:39 pm

    I never own this 20mm lens but in the days I work for a Newspaper
    I sometimes used the Nikkor AF-D 2,8/20 at the Nikon F5 and it was
    supersharp ! Unfortunately it wasn´t the angle I prefer so I changed
    back to the Nikkor AIs 2,8/24 which I still use on my Nikon D800…..

    • Reply
      January 8, 2015 at 3:14 pm

      20 is pretty wide. I’d like to test the 24.

  • Reply
    Randle P. McMurphy
    January 9, 2015 at 9:00 am

    Cool Stuff even the old Nikkor N 2,8/24 which seems to be the
    same optical formular like the Nikkor AI 2,8/24 !

  • Reply
    July 17, 2015 at 1:07 pm

    Hyper focusing on the 20 is a dream and faster than any auto focus lens.

  • Reply
    January 5, 2016 at 7:52 pm

    I recently bought this lens. It’s a beatiful little wideangle. Alas my specimen has mould, so I’m looking forward on a cleaning job… Note: the orange 22 doesn’t mean it’s AI-s, my specimen is AI and also has an orange 22 marking, but the AI-s “dent” isn’t there. Confusing eh?

  • Reply
    June 29, 2016 at 4:32 am

    I’m quite interested in this lens now. Did you test it on a Nikon body or perhaps the Sony A7? I’ve been looking for a manual focus wide angle lens for my A7 for a while now. Any chance it will show up on fstopcameras in the near future?

    • Reply
      June 29, 2016 at 12:02 pm

      Hey Ted. I tested this on a Nikon D610 which uses the same sensor as the a7, so the images you get should be directly comparable. I also shot it in. Nikkormat, I believe. This is a great lens, but it sold through the shop a long time ago. I can see what I can do to source one for you, or feel free to search one out on your own. Just let me know – will reach me fast. Thanks, my friend.

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