Nikon Df Optics

Prime
A 50mm f/1.8 prime, with excellent performance at f/8.

The Nikon Df is available bundled with a Nikkor AF-S 50mm f/1.8G Special Edition "kit" lens.

As you'd expect from a normal prime, sharpness and contrast are excellent at f/8 across the frame. Chromatic aberration is nowhere to be seen (the lens produces low amounts plus the camera suppresses it), and flare is well controlled. Really excellent performance at f/8. See below for comments on macro, geometric distortion, performance wide-open, chromatic aberration, etc.

Macro
Poor macro performance with the 50mm kit lens, as you'd expect.

The Nikon Df's macro performance will of course depend entirely on the lens mounted. However with the 50mm kit lens, the Df captured a very large minimum area measuring 8.53 x 5.68 inches (217 x 144 millimeters). Sharpness is quite good over much of the frame, though corners and edges are soft even at f/8. (Most lenses have some softening in the corners at macro distances.) This is no macro lens, and you'll definitely want to invest in a macro-capable lens for any serious close-up work with the Df.

Geometric Distortion
Moderately low barrel distortion.

The Nikon Df's 50mm kit lens produces about 0.4 percent barrel distortion, which is moderately low and just slightly noticeable. This is the tendency for the lens to bend straight lines outward (like a barrel -- usually at wide-angle) or inward (like a pincushion -- usually at telephoto).

Note that the Nikon Df offers automatic Distortion Correction. See below for details.

Chromatic Aberration, Corner Sharpness & Vignetting
Low levels of C.A. The lens produces soft corners wide-open, but sharpens up nicely stopped-down.

Chromatic Aberration. Chromatic aberration in the corners with the Nikon Df's 50mm kit lens is quite low with just minor magenta fringing, and the center of the image shows very little C.A. The camera does a pretty good job suppressing what little lateral C.A. the lens produces (see below).

Corner Softness. Wide-open, the 50mm lens that came with our Df is moderately soft in the top corners, with the upper left corner being the softest. Softness doesn't extend very far into the frame, though, and the bottom corners are a little sharper, while the center is very sharp with good contrast.

Vignetting. Moderate vignetting (corner shading) is noticeable when wide-open as indicated by the darker corner crop, even though Vignette Control was enabled by default (see below).

F8: "Stopped-down" to f/8, corner sharpness and contrast are almost as good as the center. Chromatic aberration remains quite low but as we can see from the brighter corner crop, Vignette Control over-compensated a bit, producing corners a touch brighter than the center.

Lens Corrections

The Nikon Df includes the ability to automatically correct or reduce geometric distortion, chromatic aberration, and lens shading (vignetting), as JPEG images are captured. RAW files are not corrected, but are tagged for correction by a compatible converter.

Geometric Distortion

Above is a scaled crop with Auto Distortion Correction enabled. As you can see, the kit lens shows significantly less distortion (only about one pixel's worth) than with it disabled, though extreme edges are cropped away in the process. The default Auto Distortion Correction setting is Off.

Chromatic Aberration

Above, you can see higher lateral Chromatic Aberration in uncorrected RAW files (right) versus camera JPEGs (left), though the difference isn't dramatic because C.A. is fairly low to begin with. Chromatic Aberration correction is automatic with no option to turn it off.

Lens Shading

The Nikon Df offers three levels of Vignette Control: Low, Normal, High, plus Off. Mouse-over the links above to see the difference the default Normal setting makes when wide-open at f/1.8 (the worst-case scenario). As you can see, corners are brightened without affecting brightness at the center. Vignette Control does not apply to multiple-exposures or DX-format images, and may increase the appearance of noise in corners.

Overall, an excellent lens for the money (about US$250 when bundled), particularly when stopped-down a couple clicks from maximum aperture. Note that optically the Special Edition 50mm is no different than the standard version lens. See our full test results of that lens on SLRgear.com.

Coverage
Fair accuracy with the optical viewfinder, excellent accuracy with the LCD monitor in Live View mode.

The Nikon Df's optical viewfinder displayed about 98% coverage in our test, and the captured image was also offset slightly to the left. Unfortunately shifts (as well as tilts) aren't all that uncommon with pentaprism finders. Still, a somewhat disappointing result given Nikon's 100% coverage specification and the price of the camera. In Live View mode, LCD coverage was however very accurate at 100% with perfect alignment, as expected.