Olympus OM-D E-M1 review – Using four thirds lenses
As the new Olympus OM-D E-M1 is the successor to the Olympus E-5 DSLR, many photographers will want to know exactly how their four thirds lenses will work with the MMF-3 four thirds to micro four thirds mount adapter.
In the past, using the four thirds to micro four thirds mount adapter on micro four thirds cameras has produced rather mixed results. While some fixed-focal-length, large-aperture lenses focused almost as quickly as their micro four thirds counterparts, zoom lenses tended to be very slow and jittery, making them useful only as a last resort.
Of course, the E-M1 features a new sensor that provides phase-detection AF when using a four thirds lens via the adapter. If the E-M1 is to be taken seriously as a successor to the E-5, then the performance of four thirds lenses should be as fast as when using micro four thirds lenses.
I tested the E-M1 with a variety of four thirds lenses using the MMF-3 adapter, most notably the Zuiko Digital 12-60mm f/2.8-4 SWD ED – a lens that many E-system users have. In use, it is a little slower than a dedicated micro four thirds lens, and it was certainly louder and more jittery, but it was usable and did find focus.
When shooting subjects a few metres away, the AF of the 12-60mm lens is actually snappy, and for most images I don’t think any E-system users will complain – especially as the ageing E-series DSLRs aren’t known for their lightning-fast AF.
It is when switching from focusing on a distant object to one in the foreground that the AF tends to become a little less smooth. However, it is not actually that slow, but rather gives the impression that it is, due to the noise coming from the AF as it operates and because you can feel it working when holding the camera.
What really separates contrast-detection from phase-detection AF is the speed of continuous AF. In the majority of CSCs that rely solely on contrast-detection AF, continuous AF can be very hit and miss. With the on-sensor phase-detection system, the continuous AF speed is excellent and usable for moderately fast moving subjects.
As an example, I used the Zuiko 50-200mm f/2.8-3.5 ED SWD four thirds lens with the MMF-3 adapter to shoot horses galloping. I found that the AF kept up admirably with the subject, bar the occasional shot (perhaps around one in six), where the AF was a little behind the camera’s 5.5fps shooting rate. Indeed, the shooting rate may have actually been more the cause of the slight miss of the continuous AF than the AF itself.
With the four thirds sensor already popular among wildlife photographers for its effective 2x lens magnification, the speed of the phase-detection continuous AF should only boost that popularity.
