As long as we can make them smaller, we can make them faster" --Seymour Cray
What is it?
Olympus' second serious prime lens in the m4/3 line up is a 45mm f/1.8 (90mm equivalent in 35mm terms). The barrel of the lens is actually smaller in diameter than the lens mount. That provides a svelte heft of 4 ounces (116g) for this small lens. But this is not a pancake lens. The 17mm f/2.8 Olympus sticks barely 3/4" (20mm) out of the mount, but the 45mm f/1.8 extends nearly 2" (46mm) from the mount. It's small, but it's not pocketable small on any of the m4/3 bodies as some of the pancakes are. Overall, it's a very similar size to the 12mm f/2 lens that was announced with it. The two lenses together give you a very interesting 24mm and 90mm street combo that's fast in aperture.
Inside are 9 elements in 8 groups, with two E-HR elements. There are seven diaphragm blades. Close focus is around 20" (50cm). Because of the narrow 27 degree diagonal angle of view you don't get much magnification (1:9) with that close focus distance. The front element does not rotate during focus and has a 37mm filter thread (which is different than the 12mm's 46mm). Stabilization Olympus style is done with the sensor, so there is no stabilization in the lens. The lens is an MSC design, meaning fast and silent autofocus on m4/3 cameras.
The lens comes with nothing but a lens cap for US$400. Olympus's page for the lens is here.
How's it Handle?
Not much to comment about here. The focus ring is smooth and easy to find. The optional hood is a bayonet type and reverses onto the lens keeping the combination small in your bag.
I will use this brief section to comment about Olympus's lens caps. With the hood on, it's a little hard to find the side releases, especially if you have big hands and fingers. But one little annoying thing is that almost all the Olympus logos are coming off my lens caps as I use the system heavily out in the real world. The logo is actually on a small black wafer that's glued into the plastic of the cap. Rough handling and wild temperature extremes seem to be conspiring to pop that logo wafer off most of my Olympus lenses. The cap without the logo wafer looks ugly. So at some point we're going to have a lot of ugly Olympus lens caps out there in the real world. I'm pretty sure that's not the image Olympus wants to promote on high-end optics.
How's it Perform?
The modest cost of this lens compared to the 12mm led many to believe it would be optically less refined. They were wrong.
Sharpness is good wide open and excellent (maybe even superb) from f/2.8 down to about f/8, after which diffraction impacts take their toll. Both center and edge performance are consistently good. While Olympus' MTF charts show a roll-off at the far corners of the frame, in practice this is not nearly as dramatic in real results as the test charts suggest. I find the corners very usable, and much more so than most telephoto lenses. In terms of resolution, this lens holds up very well on the 12mp Olympus bodies, though I can see some small corner differences in the E-M5, GH2, and G3 bodies. Still, under anyone's definition, the corners are very, very good for a fast telephoto.
The good news doesn't stop there. Chromatic aberration is also very low for a simple telephoto design, really only showing up at all in the corners, and then only barely. Easily fixable in post. Vignetting is also surprisingly well controlled. What little there is mostly gone by f/2.8, but even at f/1.8 you'll have a hard time seeing it. As if that weren't enough good news, linear distortion is invisible. Basically the infinitesimal amount of pin-cushion distortion falls into the level of "rounding error" from zero.
Again, the only real drawback I see is that you need the optional LH-40B lens hood. There's not enough recess of the front element to fully protect it from side-angle light, and I can see reduced contrast without the hood, especially wide open. This is a lens that could have really benefited from a short, pull-out style hood. Why we're still dealing with these silly hood games 50+ years into the mass market interchangeable lens era, I don't know. A hood is a functional aspect of lens performance. It seems silly to sell lenses that'll perform less than optimally without what's becoming an expensive and hard to come by accessory. What the camera companies keep messing up is the initial out-of-box customer experience. To discover that you really need an accessory, especially one that wasn't in stock on the day the product was first delivered, is not a positive customer experience.
Focus is very fast on the E-M5 and E-P3, still quite good on the older models. As noted, the focus system is MSC (Movie/Still Compatible), so the lens itself is quiet in focus, but not silent. The lens also seems to have the faster motor necessary to maximize performance for the latest Pen cameras (E-M5, E-P3, E-PL3, etc.)
This lens is impressive, and a bargain for its performance at that. Some might think it a bit long for portrait work, but I find it just about right for my preferences. The small size, the excellent optics, and the modest price mean this is a lens that should be in every m4/3 owners kit.
review source: purchased lens
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