Sigma 30mm f/1.4

Back in September I started thinking about whether it was worth investing in a new lens. The Olympus 14-42mm which I was using most of the time is decent but since it has a maximum aperture of f/3.5 it's not well suited to low-light photography, and the sensor on my E-520 seems to be very noisy at high ISO (above 200). Thinking ahead to a trip we were taking to Japan in a few months, I started looking around for a cheap prime lens (something like the 50mm f/1.8s you can get for Canon and Nikon cameras) but it turns out that Olympus doesn't make anything comparable! The closest is the 50mm f/2.0 macro, but that's $440 (versus $100-$130 for the comparable Canon and Nikon lenses). Everybody raves about its sharpness but I was more worried about the cost.

Looking around, it turned out that Olympus isn't the only company making lenses for the Four Thirds mount it uses on its DSLRs: there are also lenses available from Panasonic and Sigma. I looked into the Sigma 30mm f/1.4, which is pricy (also $440) but has a wider maximum aperture. I spent a long time reading up on the two and thinking about the pros and cons: the Olympus is supposedly super-sharp and it's a macro lens; the Sigma has a shorter focal length (I had a feeling that with the Four Thirds 2x crop factor, 50mm would be hard to use, since it's longer than the maximum focal length of my 14-42mm lens). The potential downside of the Sigma that worried me was that their lenses have a reputation on online forums for "poor quality control".

I went for the Sigma and paid a visit to B&H to pick one up. I was initially very pleased but it turned out that the one I bought had focusing problems at wide apertures (it was fine manually-focused). I called Sigma's service centre out on Long Island and the service guy was very helpful, he said that they will correct the problem for free, but it takes 10 days, and you have to send the camera as well as the lens to get a short turnaround time. He also said that since Sigma is a third-party manufacturer they have to reverse-engineer cameras to get their lenses to work with them (and by implication, they can get caught out by changes in camera design), which rings truer to me than "poor quality control". I didn't really want to risk that since the trip to Japan was rapidly approaching, so I called B&H and it turned out they had another lens at their warehouse which they brought in for me. The second lens (with a higher serial number) turned out to focus with no problems, and I haven't had any regrets about buying it.

I use the Sigma 30mm as my "standard" lens most of the time now in place of the 14-42mm Olympus I was using before, except when I want to take zoom or wide-angle shots. I've also found that the 30mm confuses people if you ask them to take a picture for you, people seem to expect a zoom, and the  longer-than-average focal length creates additional problems, so for sightseeing snaps the 14-42mm is the better bet. Technically the 30mm is very sharp, though if I'm going for sharpness I take photos at f/2 or above. It does have some problems autofocusing at wide apertures if there isn't a lot of available light, and it's slow and sometimes can't get a focus lock, so in those cases I focus manually. The wide aperture comes in very handy for portraits.