First announced way back 1979 as an AI lens, the Nikon 55mm ƒ/2.8 AIS Micro-Nikkor was released a year later in 1980 in the AIS mount. It has long been considered one of the sharpest macro lenses, so when a reader offered up a mint condition copy of the lens to test, we couldn't help but take him up on it.
The lens construction is fairly simple: 6 elements in 5 groups. The close-range correction focusing system is employed to produce very precise manual focusing results. Interestingly, the lens is still available in Nikon's current catalogue, though you may not find it on many store shelves.
At close ranges (less than 1:10 reproduction ratio) the amount of light that reaches the sensor is reduced. Most modern Nikon cameras can compensate in aperture-priority mode (if they have the aperture coupling ring) by increasing the shutter speed; otherwise, this is incumbent on the user either by research or trial and error. The following table shows the approximate amount of light loss at the various reproduction ratios:
When mounted on a DX sensor body, the lens will provide an effective field of view of around 82mm. The lens is full-frame (35mm) compatible, takes 52mm filters, and is available now for around $450.
Sharpness
Unfortunately, we don't have a test for our analyzer software that operates at macro distance: in fact, our testing would take place well outside of macro range. That said, the lens produces very sharp results. Mounted on the sub-frame D300s, the lens is excellent indeed: wide open at ƒ/2.8, the lens exhibits excellent central sharpness, with traces of corner softness. This corner softness goes away by ƒ/4, and by ƒ/5.6 it's as sharp as sharp gets. Technically, diffraction limiting begins to set in by ƒ/8, but your eyes won't notice it until ƒ/22, where a generalized softness is present in images produced with that aperture (just over 2 blur units). It's possible to stop down to ƒ/32 (or greater, depending on your focus distance), but here you'll get even more softness in your images.
On the full-frame D3x, the 55mm doesn't achieve the tack-sharp quality we saw on the D300s, but the results are still very impressive. The corners at ƒ/2.8 are a bit more obviously soft, but the performance trend is the same - your sharpest results will be obtained at ƒ/8. However, you'd be hard-pressed to notice a difference between ƒ/8 and ƒ/11. Fully stopped-down performance is good at ƒ/16, fair at ƒ/22, and best avoided at ƒ/32.
Chromatic Aberration
The 55mm ƒ/2.8 AF-S has excellent resistance to chromatic aberration, with its ''worst'' results coming on a sub-frame DX sensor body at ƒ/2.8. However its worst results are better than the majority of lenses out there, so this really isn't something you need to worry about. On the D3x sensor the amount of detectable CA is so small as to be irrelevant.
Shading (''Vignetting'')
Corner shading isn't noteworthy on the sub-frame D300s, but it is more prominent on the full-frame D3x. Even in this case, at ƒ/2.8, light falloff is just a half-stop darker in the corners than the center. At any other aperture setting, corner shading is negligible.
Distortion
The 55mm ƒ/2.8 AIS is nicely optimized to show almost no distortion. On a DX body the results are negligible: on a full-frame camera body the corners show some extremely light barrel distortion in the corners: less than +0.1%.
Autofocus Operation
The 55mm AIS Micro-Nikkor is a manual focus lens. The front element does not rotate during focusing.
Macro
The 55mm ƒ/2.8 AF-S is Nikon's shortest focal-length macro lens. It features a half-size reproduction ratio of 0.5x (1:2), and a minimum close-focusing distance of 25cm (just over 10 inches). With the PK-13 lens adapter it's possible to achieve full-size (1.0x, 1:1) reproduction.
Build Quality and Handling
The all-metal 55mm ƒ/2.8 AIS Micro-Nikkor lens has a very solid and well-built feel, common to Nikon lenses of this vintage. It uses an etched distance scale, which offers scales in both metric and imperial measurements, as well as a magnification ratio both for the lens itself and with the lens and a PK-13 adapter. The lens uses an aperture composed of seven straight blades. Also present on the lens are depth-of-field indicators for ƒ/11, ƒ/22 and ƒ/32, and an infrared index. Of course, being an AIS lens, there is an aperture ring.
The focus ring is very nicely damped for smooth turning, with just the right amount of resistance to keep your focus point in place when doing critical focus operations. The lens ends in hard stops when reaching close-focus and infinity. The 5/8'' wide focus ring, composed of a ridged soft rubber, turns a whopping 340 degrees across its entire range, allowing for accurate fine-tuning. As the lens is focused towards its close-focusing distance, there is some significant lens extension: the lens gets 1 1/4'' longer.
The lens does not includes the HN-3 hood, which adds a further 1/2'' to the length of the lens. The hood is a screw-on circular type, and probably isn't really needed for macro work given the front element is so deeply recessed at short focus distances. The lens takes 52mm filters, and will rotate during focusing.
In addition to the optional lens hood, Nikon produces a whole array of add-ons for this lens: filters, bellows, adapter rings, extension tubes, and even a slide copier.
example of that.