Nikon 50mm f/1.4G AF-S Nikkor

SLRgear Review
February 9, 2009
by Andrew Alexander

The 50mm prime lens has been a stalwart companion to many a photographer, as the 50mm focal range is generally thought to replicate the same field of view as seen by the eye. Many budding photographers seek to get a ''nifty fifty'' in order to use a very wide aperture and produce photos with sharp subjects and blurred, out-of-focus backgrounds.

Until the release of the subject lens, the 50mm ƒ/1.4G AF-S, Nikon had produced (and continues to produce) two AF-D, screw-driven 50mm lenses, with ƒ/1.8 and ƒ/1.4 maximum apertures. When Nikon elected to produce ''screw-less'' consumer camera bodies such as the D40, D40x and D60, owners of those cameras were marginalized by rendering these older-style lenses partially incompatible with the newer cameras; the lenses will mount, and function properly, except the camera cannot autofocus the lens.

The release of the 50mm ƒ/1.4G, with its built-in AF-S motor, fills this gap, giving Nikon owners a brand-loyal option that was filled by the Sigma 50mm ƒ/1.4 EX DG HSM. The Nikon 50mm ƒ/1.4G is full-frame compatible; mounted on a sub-frame (DX) camera body, the lens will produce an effective field of view of 75mm.

The Nikon 50mm ƒ/1.4G AF-S ships with a circular-style, bayonet-mounted lens hood and accepts 58mm filters. The lens is available now for approximately $440.

Update (Feb 16, 2009): We've included some data related to focus speed testing, just scroll on down to the Autofocus section.

Update (Nov 23, 2009): We've updated the alternatives section to reflect the results of new reviews.

Update (Feb 19, 2010): We've tested another 5 copies of the Nikon 50mm ƒ/1.4G lens to evaluate sample variation. Click here to see our Nikon 50mm ƒ/1.4G multi-sample evaluation!

Sharpness
The 50mm ƒ/1.4G AF-S is a sharp lens, though not as sharp wide-open at ƒ/1.4 as we would prefer. Optimal results start at ƒ/2, and by ƒ/2.8 we see excellent results for sharpness.

On the sub-frame D200, results for image sharpness at ƒ/1.4 were slightly soft and showed slight decentering: the bottom of the frame showed 3 blur units, while the top showed almost 4. Stopping down to ƒ/2 improves this profile, with a central region of sharpness of around 1.5 blur units, and slightly softer corners of 2 blur units; an optimal setting for portraits. At ƒ/2.8, the lens is almost as sharp as it gets, with results hovering in the 1-1.5 blur unit range; according to the numbers, the lens isn't at its sharpest until ƒ/8, where it shows corner-to-corner results of 1 blur unit. Diffraction limiting starts in at ƒ/11, but even at ƒ/16 we note only 1.5 blur units across the frame, offering better performance for sharpness when fully stopped down at ƒ/16, than when fully open at ƒ/1.4.

The full-frame sensor of the D3x is much more critical of the 50mm ƒ/1.4G. With the lens set to ƒ/1.4, we still note results in the range of 4 blur units, but the image is slightly uneven in its focus. Again, stopping down to ƒ/2 improves this profile, providing a small ''pocket'' of sharpness in the center of the image (~1.5 blur units) and corner softness upwards of 5 blur units. At ƒ/2.8, the image is more uniformly sharp, but it isn't until ƒ/5.6 that I would say the lens is completely sharp from corner to corner. An important clarification on this point: between ƒ/2.8-ƒ/5.6, I would say it is hard to point to a real-world example that shows off any uneven areas of focus. After all, we are looking at variances under one blur unit. But for applications where even image sharpness is critical, stopping down to ƒ/8 would be a must with this lens.

Similarly to the D200, on the D3x diffraction limiting sets in almost imperceptibly around ƒ/11, and by ƒ/16 we see corner-to-corner results of almost 2 blur units, again, sharper fully stopped-down at ƒ/16 than wide open at ƒ/1.4.

In summary, significantly soft when used wide open at ƒ/1.4, good central sharpness at ƒ/2, and at ƒ/2.8 and smaller, it shows quite sharp results.

Chromatic Aberration
Our test results show the 50mm ƒ/1.4G AF-S to be well-optimized to reduce the effects of chromatic aberration, especially at the wider end of its aperture range. On the D200, by ƒ/4 the lens shows less than 6/100ths of a percent of chromatic aberration; on the D3x, with automatic chromatic aberration removal, there is hardly any CA worth noting.

However, we haven't been able to run our RAW tests with Bibble, as that software does not yet support the D3x, our full-frame test body for this lens. When it does, we'll review this section, as I suspect the D200 isn't showing problematic corners, and the D3x is correcting them (one has only to look at the sample images to see there are some notable color shifts).

Shading (''Vignetting'')
On the D200, the 50mm ƒ/1.4G AF-S produces slight corner shading between ƒ/1.4 and ƒ/2. At ƒ/1.4, the corners are 2/3EV darker than the center, and at ƒ/2 the corners are less than 1/4EV darker than the center. At any smaller aperture, corner shading is negligible.

It's a different story on the D3x. When used at ƒ/1.4, the corners are 1 1/3 EV darker than the center. This is fairly substantial corner shading that you can appreciate more directly by looking at the sample images. At ƒ/2, the corners are just over 3/4 EV darker than the center; this reduces to 1/3 EV by ƒ/2.8, and goes away by ƒ/4.

Distortion
The 50mm ƒ/1.4G AF-S shows slight barrel distortion: on the D200, +0.25% in the corners and +0.13% generally. On the D3x this distortion is slightly more pronounced, +0.5% in the corners, and +0.25% generally. Fortunately results on both of these cameras can be corrected in a fairly straightforward manner in image post-processing software.

Autofocus Operation
The 50mm ƒ/1.4G uses an AF-S designation and is relatively fast to autofocus, racking through its close-focus to infinity distance and back, in just over one second. However, it's worth noting that the implementation of the AF-S standard is not similar to that of Nikon's higher-end lenses. Where lenses such as the 70-200mm ƒ/2.8 AF-S will snap to focus with blisteringly fast speed, the 50mm ƒ/1.4G AF-S is comparatively sluggish.

Here are the results of our focus testing. For more information on the process used to obtain these results, click here. In a nutshell, this table outlines the time it took for the lens to focus from infinity to close-focus, with the lens cap on.

As expected, the 50mm ƒ/1.4G AF-S offers the same speed regardless of the camera body to which it is attached.

The filter ring of the lens does not rotate while focusing, and neither does the focus ring (which does on the 50mm ƒ/1.4 and ƒ/1.8 AF-D models). The 50mm ƒ/1.4G AF-S is also very quiet during focus operations.

Macro
The 50mm ƒ/1.4G AF-S is not rated as a macro lens, and with a magnification ratio of just 0.15x (1:6.8) we can see why. The lens has a minimum close-focusing distance of 45 cm (about one and a half feet).

Build Quality and Handling
The lens is well-built, with durable plastic components and a metal lens mount. A rubber gasket shrouds the lens mount, protecting the lens from dust and moisture. The lens barrel is composed of a black semi-roughed finish, and the rubber focus ring shows a ridged pattern that is easy to grip. The lens features nine rounded diaphragm blades to make up the aperture, said to produce pleasing out-of-focus results.

The lens bears a distance scale that is recessed and windowed, its markings set in feet and meters. A depth-of-field scale is also present with indicators for ƒ/11 and ƒ/16 (however, no infrared index). A switch on the side of the lens allows the user to disable autofocus operations on the lens (marked as "M/A | M").

The focus ring is 3/8'' wide. The ring turns nicely; it is well-dampened, if just slightly stiffer than necessary. There will be no accidental adjustment to manual focus, though this is not to say that the ring is by any means difficult to turn. It just lacks the silky smoothness of higher-end lenses. It takes about 180 degrees of rotation for the focus ring to turn throughout its range of close-focus to infinity distance. There are no hard stops at either close-focus or infinity, though there is a slight increase in resistance to let you know you've reached a limit. The lens will focus slightly past infinity.

It's worth noting that the front lens element does move slightly during focusing operations, but the lens housing forms an effective shroud and thus the overall exterior dimension of the lens does not change.

The lens ships with the HB-47 lens hood, a small circular-style bayonet-mounted hood that adds 1 1/4 inches to the lens' overall length when mounted. The lens reverses for storage on the lens.

We don't usually test for flare, but in casual testing with the lens we did note it was fairly difficult to induce flare without shooting directly into the sun. The design of the lens includes a substantial shroud, protecting the lens from veiling flare. In fact, we couldn't detect much of a difference in image quality with or without the lens hood attached. Without a standardized test however, it's best to take those results with a healthy grain of salt.

Alternatives

Nikon 50mm ƒ/1.4D AF Nikkor ~$340
On paper these lenses are quite similar, though the new lens uses 9 rounded diaphragm blades compared to this lens' standard 7. The 50mm AF-D uses 52mm filters instead of 58mm. Optically, the results for sharpness CA, distortion and vignetting are similar between the two lenses, though our tests have shown the AF-D version to autofocus much more quickly.

Sigma 50mm ƒ/1.4 EX DG HSM ~$490
Mounted on a sub-frame (APS-C) dSLR, the Sigma 50mm ƒ/1.4 shows slightly sharper performance than the Nikon when used wide open; stopped down, the Nikon overtakes it for maximum sharpness. When used on a full-frame dSLR, the Sigma shows sharper central performance, matched with off-the charts corner softness. Which is better? That's in the eye of the beholder. Results for CA and distortion are similar; light falloff is a bit more noticeable on the Sigma 50mm, especially on a full-frame body. The price tag on the Sigma is also a bit more significant.It's a substantially different lens: twice as heavy, significantly larger, taking 77mm filters instead of 58mm.

Nikon 50mm ƒ/1.8D AF Nikkor ~$120
The 50mm ƒ/1.8 is comparable to the new 50mm ƒ/1.4G in terms of sharpness - the results are neck and neck, though again, we have only tested the 50mm ƒ/1.8 on the D200. The 50mm ƒ/1.8 shows slightly more CA, corner shading is about the same, but the 50mm ƒ/1.8 has virtually no distortion.

Nikon 35mm ƒ/1.8G AF-S DX Nikkor ~$199
With a 52mm equivalency on DX camera bodies, and a much more approachable price point for D40 / D60 owners, this lens may be just what they're looking for. The lens is very similar to the 50mm f/1.4 in terms of sharpness, CA and light falloff, though the 35mm focal length presents a bit more barrel distortion.

Conclusion
The Nikon 50mm ƒ/1.4G AF-S tested well in our labs, marred only by soft results with significant corner shading when set to its widest aperture. Set to ƒ/2 it makes a nice portrait lens - sharp center, soft corners - and by ƒ/2.8 it's a decently sharp lens across the image. We were a bit surprised by the slower performance for autofocus, leading us to wonder what target audience Nikon is aiming for. The professional crowd, equipped with camera bodies that support the 50mm AF-D screw-driven lenses don't need the AF-S standard in the same way that screw-less bodies like the D40/D60 do.

Whether or not you need the new 50mm ƒ/1.4G comes down to a few factors:

1. The new 50mm ƒ/1.4G AF-S is much quieter during focus operations than the AF-D, making it much more subtle.
2. Then again, the older 50mm ƒ/1.4 AF-D is much faster at autofocusing, when mounted on a pro body.
3. But - the new 50mm ƒ/1.4G AF-S has a weather-sealing gasket.

Not necessarily an easy decision!

In some ways, the decision to buy or not to buy is simple: if you have a D40, D40x or D60, and you want a 50mm lens that autofocuses, you want this lens or the Sigma 50mm ƒ/1.4 HSM. Or, if you just want the equivalent of 50mm, you may be interested in the Nikon 35mm ƒ/1.8G AF-S DX. But shooters currently using either of Nikon's 50mm AF-D lenses may want to do some comparison shooting before deciding to trade up.

Sample Photos

The VFA target should give you a good idea of sharpness in the center and corners, as well as some idea of the extent of barrel or pincushion distortion and chromatic aberration, while the Still Life subject may help in judging contrast and color. We shoot both images using the default JPEG settings and manual white balance of our test bodies, so the images should be quite consistent from lens to lens.

Still Life shot

VFA target

As appropriate, we shoot these with both full-frame and sub-frame bodies, at a range of focal lengths, and at both maximum aperture and ƒ/8. For the ''VFA'' target (the viewfinder accuracy target from Imaging Resource), we also provide sample crops from the center and upper-left corner of each shot, so you can quickly get a sense of relative sharpness, without having to download and inspect the full-res images. To avoid space limitations with the layout of our review pages, indexes to the test shots launch in separate windows.