M. Gotts
Ive owned Olympus OM-D E-M5 camera body since Christmas 2012. Using the kit 12-50mm and the 40-150mm (24-100mm and 80-300mm 35mm equivalent) lenses Ive had a fun year capturing photos. The camera has been everything I wanted it to be, with the exception of being just average tracking kids playing soccer. But the 12-40mm f/2.8 lens takes the camera to a different level. I thought I was getting decent performance from the 12-50mm lens -- and I thought wrong. Its okay, for what it is, but its slow (f/6.3 at 50mm) and just average in sharpness. With nothing to compare to, I didnt realize how it was holding back the E-M5s potential. The 12-40 is truly top caliber. Sharp from corner to corner. Chromatic aberration cannot be found. Fast for extending the E-M5s low light capabilities at modest ISOs (I can gain nearly three stops from the 12-50mm in many situations). On the PC Ill zoom in on shots and be astonished by the crispness that simply didnt exist before. Having never owned an expensive DSLR (I had a decent Nikon FE2 film body and some Vivitar Series I lenses in the 80s, however), Id been lulled into thinking the images I was capturing were simply all that such a camera was capable of. The E-M5 is a very good micro four thirds body, after only the new E-M1. What difference could one lens make? Well, as it turns out, a great deal. The 12-50mm has a smooth motor drive mode for video (which I rarely shoot) and a dedicated macro mode, which is nice. But the 12-40mm, while not being optimized for macro, turns out to be a fully capable macro lens as well, better than the 12-50, IMHO, because of its superior resolution and significantly faster performance and ability to isolate at f/2.8. The only step up for close up photography being to a dedicated macro lens. (And yes, I know that with regards to depth of field it is twice that of a full frame sensor. But f-stop is dimensionless, and with regards to light-gathering-per-sensor-size/exposure/ISO, f/2.8 is f/2.8 is f/2.8, whether it be APS, M43, full frame or a large format camera.) The only thing I dont like is the price. $1,000 was a big chunk. But the way it has changed the performance of the E-M5 is truly revelatory. There really is a significant optical difference between a decent mainstream consumer lens and a pro level lens. The 12-40 lives on my camera now, and the 12-50 is going to end up on eBay. If youve got the E-M5 or M1 and can afford it, this lens is a no brainer and will not dissappoint. Since the long end is only 80mm equivalent, I think even Lumix body owners can enjoy its benefits despite not having the in-camera stabilization that Olympus bodies have.