Olympus M.Zuiko Digital ED 8-25mm f/4.0 PRO
OLYMPUS HAS BEEN unwavering of its support of the Micro Four Thirds sensor format and it’s been backing this up with some very desirable lenses that have no doubt increased its appeal. As it happens, the winner of this category last year was the M.Zuiko Digital ED 100400mm f/5.0-6.3 IS, and it’s now Olympus’s exploits at the other end of the focal range that have collected the gong.
The M.Zuiko Digital ED 8-25mm f/4.0 PRO – equivalent to 1650mm – joins Olympus’s PRO series of higher-performance lenses, and it’s yet another demonstration of what can be achieved with the mirrorless camera configuration. An ultra-wide to standard zoom is quite a challenge in optical terms, but the 8-25mm is consequently very versatile in its applications, ranging from landscapes to portraiture. Olympus has opted for a workable balance of maximum aperture, lens size and, of course, affordability while also maintaining optimum image quality across the focal and focusing ranges. A maximum aperture of f/4.0 is the key here, and it’s quite acceptable these days given the better high ISO performance of both the latest Olympus and Panasonic M43 camera bodies.
The hugely complex optical construction reveals the lengths that Olympus had to go to make the 8-25mm work, and work to the performance levels required before it can wear the ‘PRO’ badge. No fewer than eight of the 16 elements are special types, and seven of these do different things. A couple have multiple roles – notably the two EDA elements that are both aspherical and has extra-low dispersion characteristics, and the one DSA element which is a dual-sided aspherical, meaning both its surfaces have been shaped to correct, primarily, for distortion but also sagittal flare (a.k.a. comatic aberration).
Just to spice things up a bit more, Olympus decided to give the 8-25mm useful close-up focusing capabilities too, so the maximum magnification ratio is 1:2.38 – a little under half life size – and the minimum focusing distance of 23cm is maintained across the full focal range.
PRO series M.Zuiko Digital lenses also have to meet certain standards of physical construction, so the 8-25mm employs metal alloy outer barrel tubes and weather protection measures to the IPX1 standard with insulation to allow for shooting in subzero temperatures down to -10ºC. The focusing ring incorporates Olympus’s Manual Focus Clutch arrangement, which really is the quickest way of switching between auto and manual focusing – push and pull, and if you can see the distance scale, the lens is in manual focus mode. Simple.
In performance terms, the 8-25mm is very sharp and very highly corrected for a zoom lens with ultra-wide capabilities. Significantly, most of the correction is done optically rather than relying on in-camera processing of the image data. It’s probably a matter of pride for a company with such a rich heritage of building exceptional lenses, and it deserves to be recognised.