The Rokinon 16mm T2.2 Cine DS ($599) is just one in Rokinon's line of affordably priced manual focus lenses for SLRs and mirorless cameras. As part of the Cine DS series it features a geared design that can be used with a focus pulling system. It covers a very wide field of view, and opens up all the way to t/2.2 for low-light photography and videography. It's a good choice for APS-C SLR owners, and occupies a fairly unique place in the market—none of the major SLR systems offer a comparable autofocus lens for cropped cameras. But if you shoot with a mirrorless camera you may find it to be a bit bulky, as compact options like the Olympus M.Zuiko Digital 17mm f1.8, the Samsung 16mm f/2.4, and the Sony 16mm f/2.8 are available.
Editors' Note: This review is based on tests performed on the Samyang 16mm F2.0 ED AS UMC CS. Aside from the mechanics and branding, the lenses are optically identical, and we expect similar performance.
DesignThe 16mm measures 3.4 by 3.4 inches (HD) and is a bit hefty at 1.3 pounds. Its size isn't an issue with an SLR, but it may be a bit much for mirrorless systems. It covers a field of view that's equivalent to a 24mm prime on a full-frame camera, although it doesn't offer a big size advantage over the Sigma 24mm F1.4 DG HSM Art, which is 3.6 by 3.3 inches and 1.5 pounds.
The barrel is composite plastic, but it's sturdy; the lens doesn't feel cheap in any way. Gears adorn the barrel, so the focus can be adjusted with a focus pulling system. The distance scale, as well as the aperture scale, are printed on both sides of the lens, so the focus operator can sit at either side. There's no rubber cover on the focus ring, as there is with the version of the lens designed for use for still photography, so you may find it a bit uncomfortable to turn by hand. The ring does turn smoothly, with a 180 degree throw to move from the minimum 7.9-inch (0.2-meter) focus distance to infinity. A reversible lens hood is included. The aperture can be adjusted from t/2.2 through t/22; there are no click stops.
Rokinon sells the lens for several camera systems. Owners of Canon, Nikon, and Sony SLRs can find the lens in a native mount, as can mirrorless shooters who use Micro Four Thirds or Sony cameras. It can also be purchased as the Samyang 16mm T2.2 VDSLR ED AS UMC CS II. If you prefer a version of the lens that's better suited for stll capture, conisder instead the Samyang 16mm F2.0 ED AS UMC CS or Rokinon 16mm F2.0 ED AS UMC CS. Each has identical optics.
Image Quality and ConclusionsThe lens is intended for use with APS-C (Super 35) and Four Thirds sensors, but it can mount on full-frame cameras. I used it with the full-frame Nikon D810. The D810 has a DX (APS-C) in-camera crop mode which utilizes the center of its 36-megapixel image sensor to capture 15.4-megapixel photos. But I found that, if you're willing to deal with darkening and softness at the edges of the frame, a slightly wider swath becomes useable. I pulled some acceptable 20-megapixel crops from the full-frame image, an effective field of view that's more like 21mm than 24mm. The image above is an uncropped shot from the D810, showing what you'll see when peering through a full-frame viewfinder.
I used Imatest to check the sharpness of the lens when paired with the D810 in its APS-C crop mode. At t/2.2 it scores 2,483 lines per picture height on a center-weighted sharpness test, better than the 1,800 lines we like to see in an image. Performance is strong right to the edge of the frame, with only a slight drop in crispness (2,262 lines) when compared with the center.
There's improvement as you stop down. At t/2.8 the lens improves to 2,573 lines. It crosses the 2,600-line mark at t/4 and peaks at t/5.6 (2,659 lines) and t/8 (2,686 lines), before dropping slightly at t/11 (2,639 lines). Diffraction takes its toll on photos at t/16 (2,389 lines) and t/22 (2,221 lines).
Barrel distortion is modest, about 1.4 percent. If you're photographing an image with straight lines or a clear horizon you'll probably notice a slight outward curve. There is some dimming at the edges of the frame. Expect corners to drop about four stops when compared with the center at t/2.2, and about two stops at t/2.8. Beyond that you'll still have to deal with about -1.5EV loss at the corners, which is noticeable, but not terribly distracting. Software tools, like Adobe Lightroom CC, can be used to remove distortion and brighten the corners of the frame if you find either effect distracting.
If you don't mind—or if you prefer—manual focus, the Rokinon 16mm T2.2 Cine DS is a fine choice for an SLR. It's especially well suited for APS-C models, capturing sharp images from edge to edge, even wide open, when paired with a camera like the Canon Rebel or the Nikon DX. But if you're a full-frame user and can deal with the loss of sensor resolution that shooting with a cropped area entails, don't count it out—it won't give you 16mm coverage, but it can crop down to about 21mm nicely. Mirrorless shooters may find that it's a bit big to pair with a compact camera, but it will deliver the true feel of a mechanical focus system that most electronic focusing mirrorless lenses lack, and focusing manually with a magnified view on a rear LCD or electronic viewfinder is a more precise experience than doing so via an optical viewfinder. So if a wide-aperture, manual focus lens appeals to you, this 16mm t/2.2 is an excellent option.
Source: Rokinon 16mm T2.2 Cine DS
No comments:
Post a Comment