PROS
- Sharp. Wide-angle field of view.
- Minimal distortion.
- Resistant to dust and splashes.
- Excellent build quality.
- Available for Canon and Nikon SLRs.
CONS
- Dim corners, even when stopped down.
- Manual focus isn’t for everyone.
- Expensive.
BOTTOM LINE
The Zeiss Milvus 2.8/21 is a gem of a wide-angle lens, combining crisp optics with minimal distortion in a solid, manual focus design.
Design
The 2.8/21$1,649.95 at Amazon measures 3.6 by 3.8 inches (HD), weighs 1.6 pounds, and supports huge 82mm front filters. It includes a reversible petal-style lens hood that is constructed from the same matte black metal as the barrel and has a felt-lined interior to minimize reflections. The lens is finished with a seal at its mount point and offers additional internal seals that protect it and your camera from dust and slashes. The focus ring is covered in soft rubber, which makes it a bit more comfortable to turn when compared with bare metal.
You can buy the 21mm prime for a Canon or Nikon SLR. The Canon version features purely electronic aperture control, typical of the EOS system, both digital and 35mm. The Nikon edition has a physical aperture ring that can be adjusted in full-stop increments or can be set to turn smoothly for video use. Of course, when paired with a modern Nikon D-SLR you can set the f-stop to f/16 and control the aperture via the camera body, just as you can with any modern Nikkor lens. Both versions of the lens communicate with the body so that working aperture and focal length are recorded in the EXIF data of images.
The Milvus focues on subjects as close as 8.7 inches (22cm), measured from the focal plane, so you can get up close and personal with subjects, to the point where it can capture objects at 1:5 magnification—not too shabby for an ultra-wide lens. You don’t typically associate a shallow depth of field with a 21mm lens, but when working close at f/2.8 you’ll get a background blur behind your plane of focus.
A good focus scale is an important aspect of a lens this wide, and the Milvus has one. It’s engraved with white paint, and marked in meters and feet. Depth of field is shown for full stops from f/4 to the minimum f/22 supported by the lens. Even though the focus throw is long for a wide-angle lens—about 90 degrees—it’s practical to preset focus, stop down the lens, and not worry about focusing before a shot. At f/8, for example, everything from about 4 feet to infinity will be in focus when the infinity mark is placed above the f/8 depth marking.
Image Quality
I tested the Milvus 2.8/21 along with the 36-megapixel Nikon D810$3,296.95 at Dell. At f/2.8 the lens scores 2,954 lines per picture height on Imatest’s center-weighted sharpness test. There’s some curvature to the field of focus, which results in a crisp center (3,339 lines) and very sharp edges (2,935 lines), but mid parts that lag behind both (2,451 lines). All of the areas of the frame score above the 2,200 lines we look for in results from a high-resolution camera.
At f/4 the mid parts and center both improve, bringing the average up to 3,218 lines, and at f/5.6 the edges and mid parts of the frame have evened out, while the center has improved further, bringing the overall score to 3,556 lines. It increases to 3,895 lines at f/8. If near even image quality from edge to edge is important, set the lens to f/11, its sharpest setting (4,013 lines). Diffraction cuts into image quality at f/16 (3,715 lines) and f/22 (3,159 lines).
There’s about 1.3 percent barrel distortion, which give straight lines a slight, perceptible outward bow. If it detracts from your shot it’s easily corrected in Lightroom, but it’s a modest amount for an ultra-wide lens. Illumination is more of an issue. Imatest’s Uniformity analysis shows that corners are 3.7 stops dimmer (-3.7EV) than the center of the frame when the lens is shot at f/2.8. Stopping down cuts the deficit, but it’s still a very noticeable drop at f/4 (-2.5EV) and a lesser, but visible, deficit at f/5.6 (-1.6EV). At narrower apertures the corners are about 1.2 stops dimmer. You can compensate for dim corners in Lightroom; there is a profile for the lens so both can be rectified with a single click.
Conclusions
Like the other manual focus lenses in the Milvus line, the Zeiss Milvus 2.8/21 is an excellent performer. It captures crisp images—when stopped down it takes full advantage of a high-resolution image sensor—and its sturdy build allows you to use it in all sorts of weather. You pay a premium for a Zeiss lens, but the 2.8/21 lives up to its asking price. Fans of ultra-wide lenses should take note.
Source: pcmag.com
