After the recent TOP print sale, I decided to splurge on a trio of fast prime lenses for my Olympus Pen E-P1. Eventually I will get around to reviewing the Olympus 12mm ƒ/2 and 45mm ƒ/1.8 lenses, but I'm starting out with the Rokinon 85mm ƒ/1.4 telephoto. Why? Well, because that's the one I got first and have been able to put through its paces. You'll get the other two reviews by the end of the year, I promise.
This is the sort of lens that helps justify the existence of a format like Micro 4/3. On a full-frame camera, this is a modest telephoto of modest quality at a modest price ($270). On a micro 4/3 camera it's the equivalent of a 170mm ƒ/1.4 lens. Try paying for one of those for your full-frame camera, why don't you? Too rich for my blood. Even tossing in the cost of the 4/3-to-Micro 4/3 adapter that I didn't yet own, it wasn't big bucks for such an extraordinary combination of focal length and aperture.
Some negatives: as you'd expect it's huge and heavy; at 600+ grams, it significantly outweighs the camera body. It's also bigger. It's a manual focus lens. That, I expected. It's also a manual aperture lens. That, I didn't. The B&H website doesn't mention that. Just so you know. I am able to live with the former more easily than the latter. If I knew of an automatic-aperture lens with comparable quality that wasn't hugely more expensive, I'd probably have returned this lens and gotten that one. I don't, so I'll live with the warts.
Originally I bought an open-box sample from B&H to save about 30 bucks. Optically it was just fine, and it looked to be in perfect condition. But rotating the focusing ring produced a grinding noise. I mean, it was audible! Back it went to B&H, no problem, and I bought a new one. No grinding noise. Still, I doubt that a lens this inexpensive is designed to take really hard knocks. I do not intend to test it to destruction.
This is the lens I used for most of my photography at the 100 Year Starship Study conference. It handled very nicely, better than I expected. The huge front element barrel makes for a convenient place to grab onto the lens. Nice, since you really don't want to be touching the focusing ring unless you're focussing. Wide open, depth of field is razor thin and critical sharpness appears and disappears with a fraction of a millimeter turn of the barrel. If you're working at ƒ/1.4, you're going to find getting the plane of focus exactly where you want something of a challenge. Not the fault of the lens, it comes with the territory.
For handheld work, keep image stabilization on unless you're working at really high shutter speeds. With IS, I could reliably handhold this lens at 1/40–1/50 second (reliable meaning that half my photographs came out acceptably sharp). That gets me to some pretty low-light situations without having to kick the ISO into the stratosphere. That's why wanted this lens. At high ISOs, this is one of those "if you can see it, you can photograph it" optics.
On a tripod, it definitely works better to turn image stabilization off. I got slightly wonky results on my early resolution tests until I figured that out. The results with stabilization on aren't awful, they're just less than optimal.
Okay, so how does it look? Not the lens, the photographs? Wide open, the lens is entirely usable (illustrations 1 and 2). There is some residual astigmatism and coma visible at the edges but it shouldn't be too distracting (illustration 3). Vignetting, wide open, is less than half a stop center to corner (it's under a quarter-stop at ƒ/2). There's almost no lateral chromatic aberration; that's impressive. On the other hand, there is a great deal of longitudinal chromatic aberration. You can see that in illustration 1 by looking at the bright highlights in front of and behind the plane of focus. Notice how the highlights on the glass tray have a pronounced magenta fringe while the highlights on the plants in the background are a pronounced green (and, no, that's not due to the color of the leaves; it's equally prominent in subjects with neutral background highlights). This is what mostly contributes to the softness of the lens wide open. It's not an unpleasant softness, just a slight hazy quality. Really, I am comfortable using this lens at ƒ/1.4 if I have to.
4. and 5. One of my test images. Above, full-frame. Below, the upper-right corner at 100% magnification at various apertures.
By ƒ/2.8 uniformity across the field is much, much improved, and central sharpness has perked up; I'd call this the largest aperture for good results over the entire field (illustrations 4 and 5). Peak sharpness in the center is at ƒ/5.6, although there's very little difference between that and ƒ/8. Diffraction really doesn't take an unacceptable toll until you get beyond ƒ/11. Uniformity continues to improve as the lens is stopped down. It's very good at ƒ/5.6 and excellent at ƒ/8. If central image quality is most important, ƒ/5.6 is the optimum aperture (illustrations 6 and 7); if overall quality across the field matters more, then ƒ/8.
6. Flare is a major problem with this lens when there are large bright areas
near the edge of the frame. It's a function of those huge front elements,
and it's only modestly improved by stopping down, as demonstrated
in this image made at ƒ/5.6.
An expected issue with a lens like this is flare, and it is present in abundance. Although a lens hood's included, any very bright areas at the edge of the field of view of the lens are going to produce significant flare, as is evident in illustration 6. No way to work around this; one just has to try to avoid such situations or live with the results.
7. These are 100% sections from illustration 6. Stop ƒ/5.6 produces the best center sharpness, along with very good image quality at the edges. For optimum overall uniformity, go down another stop to ƒ/8.
Overall, I'd call this a decent lens, not a spectacular performer but good enough. It's a solid keeper. Understand that that's a price-sensitive matter; if this were a $1,000 optic I'd expect a lot better than decent performance (and an automatic aperture!), and it would be back to B&H with it. At a quarter that price, I consider it a bargain. It will serve me well in low-light situations and, stopped down, I think I can do quality work with it in the outdoor daytimes.
(Ed. Note: I've included Amazon as a link for those interested in checking out the catalog listings, because B&H is on holiday this week.)
Ctein's regular weekly column appears on TOP on Wednesdays.
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Original contents copyright 2011 by Michael C. Johnston and/or the bylined author. All Rights Reserved.