It wasn’t so long ago that you could find a fixed 50mm lens in the bag of almost every photographer. With a magnification, on 35mm film, that is similar to human vision, fixed 50mm lenses came with the majority of new cameras. Over the years, the design of 50mm lenses became fine-tuned to produce some of the sharpest and least distorting optics ever produced.
Nikon first produced a manual-focus 50mm f/1.8 lens in 1978, and in the same year also introduced a cheaper version: the 50mm f/1.8 E series. The first autofocus version followed in 1986, and this was updated in 2002. This newer AF lens was the 50mm f/1.8D, which communicated focus distance information to the camera to help improve exposure calculations. The one thing all these lenses have in common is the same basic optical design, featuring an arrangement of six elements in five groups.
Announced in April this year, the Nikkor 50mm f/1.8G changes the optical arrangement of the Nikkor series of 50mm f/1.8 optics for the first time in over 30 years. As well as being optically different, the lens also features some major mechanical changes to bring it into line with the rest of the current Nikkor lens range.
Features
Perhaps the first noticeable difference in the new 50mm f/1.8 lens is that it is a G-series model, meaning that it doesn’t have an aperture ring. Although there are still a handful of older D-series optics in Nikon’s line-up, the vast majority of the company’s AF lenses are part of the G series, which as standard don’t have aperture rings.
Although this will be frowned upon by some, G-series lenses can be used with all Nikon AF cameras, whether film or digital, going back as far as 1986. However, they are not compatible with manual-focus cameras.
One major advantage of the new lens comes via the introduction of an internal AF motor. The two previous AF versions of the 50mm f/1.8 optic rely on a motor in the camera to drive an AF screw in the lens.
This means that neither the original nor D versions of the 50mm f/1.8 lenses work on the entry-level Nikon DSLRs, such as the D40, D40X, D60, D3000, D3100, D5000 and D5100. The fact that the new AF motor is a Silent Wave Motor (SWM) is an added bonus, meaning the new lens should be fast and quiet when focusing – great news for those wishing to shoot video.
Of course, it is the optical changes that will most interest photographers. The introduction of a new aspherical element takes the construction of the 50mm f/1.8G to seven elements in six groups, and is designed to reduce comatic and chromatic aberrations. These optical distortions have previously been most prevalent when shooting with a large, fully open aperture, and are the Achilles’ heel of many a 50mm f/1.8 lens.
Designed primarily for digital camera sensors, the new lens has been coated using Nikon’s Super Integrated Coatings, which should help to improve colour accuracy and contrast, and reduce ghosting. The aperture blades themselves have also been improved and are now curved to create almost circular bokeh, compared to the heptagonal shape created by the older lens aperture designs.
So, while the emphasis may be placed on the inclusion of an aspherical element, there are a number of other small changes that should significantly improve the performance of the new 50mm f/1.8G lens.
Build and handling
Due to the built-in AF motor, the new 50mm f/1.8G lens is larger than the two previous 50mm f/1.8 AF optics. The larger diameter of the new lens means that the filter thread is now 58mm, as opposed to 52mm on the older versions, and its weight is fractionally increased, from the 160g of the 50mm f/1.8D to 185g.
The increased size of the G-series lens means the rubberised manual-focus ring is also larger than on previous models. But this is something of a paradox: with no aperture ring on the lens, it cannot be properly used on a manual-focus Nikon camera. However, it does prove useful when shooting in live view to ensure the subject is precisely in focus.
Despite being one of the cheapest Nikkor lenses, the 50mm f/1.8G doesn’t scrimp on build quality. It has a metal lens mount that is weather-sealed by a rubber surround covering both the lens and body mounts when the optic is attached to the camera. Sealing the connecting mounts in this way helps to prevent the incursion of moisture and dust.
Like most other Nikkor AF lenses, the 50mm f/1.8G features a switch on its side to change between two focus modes: M/A and M.
When switched to M/A, the lens will focus automatically and then, with the shutter button still half-depressed, you can adjust the focus manually. When switched to M, AF is disabled completely and the lens becomes fully manual focus. Again, this feature was not present on the previous incarnations of this lens.
Considering its price, the 50mm f/1.8G lens has a premium build quality. About the only feature lacking is Vibration Reduction, but this is largely unnecessary in a lens of this focal length and such a large maximum aperture.
Focusing
With its internal Silent Wave Motor, the first thing that is apparent when using the 50mm f/1.8G is how quiet the lens is when focusing compared to its predecessors. Without the buzz of an AF screw driving the lens focus mechanism, there is a noticeable quietness.
The low volume gives the impression that the 50mm f/1.8G focuses faster than the previous AF versions of this lens, but it is just that – an impression. Focusing on a subject a few feet away, and then to infinity, took the same amount of time regardless of which version of the lens I used.
When using the D3X professional-level DSLR, I found that all of the lenses quickly snap into focus, making the new model a great choice for documentary images and travel photography. Its 75mm equivalent field of view on a Nikon DX-format (APS-C-sized sensor) DSLR makes it a nice short-focal-length portrait lens.
Image: When shooting wide open at f/1.8, the lens gives a very shallow depth of field
Image quality
There are three main benefits to using an f/1.8 lens: the large aperture allows you to shoot in low-light conditions; the large aperture will produce a very shallow depth of field, which can be used creatively; and the aperture can be closed to f/2.8 or f/4 for optimal performance, but continue to offer a shallow depth of field.
Image: The Nikkor f/1.8G lens is ideal for low-light portraits
While half the fun of 50mm f/1.8 optics is using them fully open, this is also when they will optically be at their worst.
Looking at all four of the Nikkor 50mm f/1.8 lenses, it is clear to see the evolution in the lens design. The new G series optic has the least coma and chromatic aberrations of all of the lenses – presumably is a result of the new aspherical element.
Image: The Nikkor 50mm f/1.8 lenses: Top Left: AF-D. Top right: the new G series. Bottom left: original AF. Bottom right: manual E series
The improved multi-coating of the 50mm f/1.8G has also boosted performance, adding a good level of contrast compared to past lenses. This has helped to increase image definition, again, particularly when one is shooting at f/1.8.
It is, of course, image sharpness that all lenses will be judged by, and in this regard the 50mm f/1.8G performs extremely well. Tested using the 24.5-million-pixel Nikon D3X, the new lens resolves around the same amount of detail as its predecessor but produces better contrast and less chromatic aberration at wider apertures. As you would expect for a fixed-focal-length lens, it is extremely sharp, picking up very fine details with impressive clarity.
However, the new lens does have a few slight flaws, including a little more barrel distortion than with previous versions. This should not be too much of a concern for photographers, especially those using cropped DX-format (APS-C-sized) sensors, as these use the centre of the lens where any curvilinear distortion is far less noticeable. The distortion is also very easily corrected in software.
Vignetting is also present when the lens is at its widest aperture, but once again it is not severe and is easily corrected, so it will not be an issue for those shooting with DX-format Nikon DSLRs.
Resolution
All of the resolution chart images were taken on a 24.5-million-pixel Nikon D3X. Whilst the lenses can resolve an almost identical resolution at their optimum aperture, the latest G series lens is slightly sharper when fully open, and shows less chromatic aberrations and coma. However, the other lenses all stop down to f/22, compared just f/16 on the new G series lens.
Our verdict
Improving on a classic design is often a difficult task, but it is one in which Nikon has succeeded. The new 50mm f/1.8G lens adds some significant features such as a quiet Sonic Wave Motor, curved aperture blades, better image contrast and reduced chromatic aberrations.
Curvilinear distortion may be slightly worse than with the previous design, but is still not very significant, especially if you don’t use a camera with a full-frame sensor.
There are few lenses that I would suggest photographers of a particular brand should own, but the Nikkor AF-S 50mm f/1.8G is one of them. With a street price of around £200, it is Nikon’s cheapest full-frame lens, with only the 18-55mm f/3.5-5.6 DX kit lens costing less.
Regardless of your Nikon DSLR or photographic interests, the 50mm f/1.8G should find a place in most Nikon users’ kit bags, especially given its price and the quality of images it produces.
