Other people have reviewed the Zuiko ED 50mm f/2.0 macro lens with more scientific measuring devices, and they say this is the sharpest lens that Olympus makes. I’m not going to argue with that. I don’t really even know how to test that assertion with my Olympus E-500 DSLR, because as I’ve written before, the Olympus E-500 is not as sharp a camera as a Canon G9 point and shoot.
The reason I bought this lens is to use as a portrait lens. The goal is to obtain a shallow DOF in order to get a pleasing and out-of-focus background. This is the fastest portrait-length lens which Olympus makes, so there isn’t any other choice. Olympus really ought to come out with a f/1.4 lens in a good portrait length, which would be 43mm in order to match the standard 85mm portrait lenses used on full frame cameras. Instead, Olympus just keeps coming out with more zooms covering the same focal lengths.
One of the common complaints about this lens has to do with focusing speed. I find that in decent light, the lens focuses fast enough and I wouldn’t realize that I’m not using one of the several Olympus zoom lenses that I own. However, the focusing is a real train wreck in a dimly lit room if you miss focus, because then the lens takes a long journey throughout the entire focusing spectrum. Even if it doesn't cycle through the whole lens, focusing is still a lot slower indoors, although my camera has this problem with all lenses, so I blame the camera rather than the lens. If you are thinking that this lens will allow your E-500 to see in the dark because of its large aperture, think again. Maybe if you have one of Olympus’ newer pro-level cameras, it will focus better in dim light, but who knows?
Now for some photographic examples.
The first photo is of a building at a distance, shot at f/4.5. The lens performs admirably well in this situation.
Here is a 100% crop of the lower left corner:
Pretty good, I don’t see any chromatic aberrations or obvious corner softness. However, I certainly didn’t buy this lens to take this type of photo, I could have just used the 14-54mm f/2.8-3.5.
Let’s open up the aperture to 2.0 and see what happens:
I focused the camera at the woman’s head.
The background is somewhat out of focus, but not by an extreme amount. Obviously you need a lens with a larger aperture on an Olympus DSLR to get the same shallow depth of field that you would get with a Canon 5D mk II. Unfortunately, Olympus doesn’t make such a lens.
Let’s take some closer looks at this photo:
Notice the red fringing around the tree trunk and the green fringe around the concrete. There is quite a bit of fringing!
Look at all those green fringes around the water in the above crop.
In the photo below, I focused on the tree trunk (and then recomposed):
If the tree trunk were a six foot tall person, that’s about where he would be standing in order for you to get a full length portrait (head to feet) with a little bit of headroom. As you can see, while the background is more out of focus than would be the case if you were using a p&s camera, it’s not quite what you would get from a full frame camera.
The crop above shows more weird green fringing in the bokeh.
In the crop above, we see that the tree leaves in the bokeh turn into little hard-edged circles. That’s generally considered an example of bad bokeh. A lens with good bokeh has a creamy blurriness.
SPHEROCHROMATISM
There is a special term for these color fringes in the bokeh, and it's called spherochromatism. There are green fringes on the distant side of the focal plane, and magenta fringes on the near side of the focal plane. This lens has a really bad case of spherochromatism. Olympus obviously designed this lens to perform really well on test charts (as it's very sharp and there's no chromatic aberration in the focal plane), but has ignored the issue of spherochromatism, which causes really ugly bokeh.
The review at dpreview.com talks about this lens’ “bokeh chromatic aberration at wider apertures.” That’s what the review was talking about, but I completely disagree with the reviewer's take that this problem has a "relatively rarely impact on the normal uses of this lens." I bought the lens to use it wide open to get shallow depth of field, and I think that a lot of people buy this lens for the same purpose.
To be somewhat fair to Olympus, other lenses also have this problem. The dpreview review of the new Pentax 55mm f/1.4 also demonstrates what they call "intense green/magenta bokeh chromatic aberration" at wide apertures.
[At an online forum, a poster complains about the bokeh CA in the Canon EF 85mm f/1.8 lens.]
FOCUS PROBLEMS
Now for the focus test. I set up a bottle of Johnnie Walker Black Label, and put a piece of standard copier paper with some text on it in front of the bottle. The bottle is approximately 7 and a half feet from the camera. The camera is on a tripod. I pointed the focus point right at the black label in the middle of the bottle. Here’s the full photo:
The photo is underexposed because that’s the crappy light metering on the E-500. White walls always confuse it. I could have set the exposure compensation to +1 EV, but this is a good opportunity to demonstrate an area where the E-500 sucks.
And here’s a crop demonstrating the focus problems:
Looking at the paper, it seems the area of sharpest focus is about 3 inches in front of the bottle.
Bad lens? I’m more inclined to blame the camera, so there’s no point in returning the lens. In fact, I've previously had the impression that my E-500 was front focusing, but it wasn't as big a deal given the wider DOF of my other lenses. The solution is to buy one of the newer Olympus cameras with focus adjustment. Now that they are making cameras with micro focus adjustment, I’d never buy a model that didn’t have it, and this focus test demonstrates why. The work-around for this focus problem is to focus, then move my head forward three inches, and then take the photo. I hope this doesn't make me look like a chicken with a bobbing head.
CONCLUSION
This is an excellent lens for taking pictures of test charts, in fact the best that Olympus makes. But as a real world non-macro lens, it's rather mediocre due to its focusing issues and bad bokeh.
Olympus really needs to come out with a fast lens oriented towards portrait photography. It's hard to believe that after six years of making DSLRs, Olympus still hasn't bothered to make a good portrait lens, even though it has made zillions of zoom lenses. Does Olympus think that people who buy its DSLRs have no interest in portrait photography?
Perhaps Panasonic will come out with a good portrait lens for its new Micro Four Thirds system. Panasonic seems to be avoiding all of the dumb marketing mistakes that Olympus made (and continues to make) with its Four Thirds DSLRs.
And that wraps up my review of the ZD 50mm f/2.0 macro lens. Sorry, no macro shots. If you want lens strictly for macro photography, why not just buy the 35mm f/3.5 for half the price? Although I personally wouldn't bother to buy a lens to do macro photography with my E-500, because the Canon G9 does better macro.
UPDATE
Further focus testing suggests that the lens is fine, but the E-500 has inconsistent autofocus.
UPDATE 2
The lens also focuses accurately on the E-620, using a test chart, no micro-focus adjustment required. But the E-620 still favors front-focusing on real-world three-dimensional targets.
