In summary
On a M4/3 camera, the 25mm focal length provides maximum shooting versatility in the most classic of focal lengths ““ equivalent to 50mm on a 35mm camera. It is ideal for everyday snapshots, portraits and landscapes as well as being suitable for street photography and photojournalism.
The fast maximum aperture of f/1.8 provides scope for shooting with de-focused backgrounds as well as minimising camera shake when shooting in low light levels. The small size and low weight (only 137 grams) of this lens make it ideal for travellers and hikers, although unlike some Olympus lenses, it lacks weatherproof sealing.
Full review
Announced with the OM-D E-M10 at the CES show in January, the M.Zuiko Digital 25mm f/1.8 fills a gap in Olympus’s Premium series of fast prime lenses, fitting between the 17mm f/1.8 and 45mm f/1.8 lenses with the 75mm f/1.8 lens completing the set. The 25mm lens covers a standard focal length equivalent to 50mm in 35mm format. Its angle of view is close to that of human vision, making the new lens good for general photography.
The M.Zuiko Digital 25mm f/1.8 prime lens, black version. (Source: Olympus.)
The asymmetrical optical design comprises nine elements in seven groups, with two of them aspherical elements. Olympus’ proprietary high-end ZERO multi-coating technology has been applied to minimise internal reflections and ensure optimal contrast.
The diagram above shows the asymmetrical optical design of the M.Zuiko Digital 25mm f/1.8 lens. (Source: Olympus.)
The MSC (Movie & Still Compatible) inner focusing mechanism provides fast, smooth, silent and high-precision autofocusing. Close focusing is possible at 25 cm from subjects, providing a magnification factor of 0.24x.
This lens is compatible with the separately-sold Macro Conversion Lens (MCON-P02). It will be offered in black and silver and is supplied with front and end caps plus a bayonet-style lens hood and a ‘decoration ring’ that covers the threading when the lens hood is not being used. (The ‘decoration ring’ was not supplied with the review lens.)
Who’s it For?
On a M4/3 camera, the 25mm focal length provides maximum shooting versatility in the most classic of focal lengths ““ equivalent to 50mm on a 35mm camera. It is ideal for everyday snapshots, portraits and landscapes as well as being suitable for street photography and photojournalism.
The fast maximum aperture of f/1.8 provides scope for shooting with de-focused backgrounds as well as minimising camera shake when shooting in low light levels. The small size and low weight (only 137 grams) of this lens make it ideal for travellers and hikers, although unlike some Olympus lenses, it lacks weatherproof sealing.
Build and Ergonomics
Although a substantial amount of polycarbonate plastic is used in this lens, it is solidly built and has a metal mounting plate that attaches firmly on the camera body with no trace of wobble or play. When fitted, the lens extends just 42 mm in front of the camera, with the lens cap adding a further 2 mm and the reversible hood taking the overall protrusion to 59 mm. You can’t fit the hood without removing the ‘decoration ring’.
The focusing ring begins about a centimetre behind the front of the lens. It’s 15mm wide and clad with narrow ribbing to provide an easy, secure grip. Olympus’s MSC (Movie and Still Compatible) autofocusing system works with the camera’s High-speed Imager AF system to provide fast, accurate and almost silent autofocusing, which enabled the lens to be used while recording movies.
Manual focusing is electronically controlled by the camera, using a focus-by-wire system that provides minimal tactile feedback. The mechanism isn’t geared to match the speed at which the ring is rotated so the only feedback to the user when focusing manually is what’s shown on the monitor screen. In-camera aids like magnification and peaking indicators provide essential aids to focusing precisely.
There’s no distance indicator and no distance scale. The only other feature on the lens is a narrow (approximately 5 mm wide) grip band with ridges along 30 mm strips on either side of the lens. This strip makes the barrel slightly wider before it contracts to form the mounting plate.
Performance
We tested the review lens on two camera bodies, the OM-D E-M5 and OM-D E-M10, which were effectively indistinguishable for both the regular Imatest tests and normal shooting. Autofocusing was as fast as each camera supports and generally very quiet, making this lens ideal for use when shooting movie clips. It took roughly half a second to shift from the minimum focusing distance to infinity in our tests.
Subjective assessment of shots straight from the camera showed them to be very slightly soft. However, they sharpened up nicely with very modest unsharp masking in Photoshop.
Imatest showed JPEG files from the E-M5 to be close to meeting expectations for the camera’s 15.9-megapixel sensor near the centre of the frame. Edge softening was noticeable at wider apertures but effectively negligible beyond f/5.6. Although very sharp at f/1.8, the highest resolution figures in our Imatest tests came between about f/2.8 and f/5.6, with a steep falling off from f/8 on, as shown in the graph of our test results below.
Lateral chromatic aberration (CA) was generally low, although not entirely absent. Its effects could be seen near the edges and corners but only in areas of high contrast, and only by viewing 100% crops.
Imatest showed CA came close to the moderate level with the widest aperture settings but was negligible at f/22. In the graph below, the red line separates negligible and low CA, the green line divides low from moderate CA.
Fortunately, easy corrections for this aberration are available in most image editing software, including raw file converters, so we don’t see it as a major issue for serious enthusiasts. Vignetting was barely noticeable at the widest aperture setting and vanished as the lens was stopped down.
Rectilinear distortion was virtually negligible, as expected for a lens of this type. Both distortion and vignetting are easy to correct post-capture so neither issue presents a serious problem.
Flare wasn’t much of an issue with this lens, thanks to an effective lens hood, which shielded the front element from all but direct light. Nevertheless, when pushed, this lens can produce faint streaking, usually towards one side of the image frame.
The f/1.8 maximum aperture produces a very shallow depth of focus for close-ups and the resulting bokeh was smooth and attractive with no outlining of highlights. The closest focusing distance of 25 cm limits the types of subjects to larger flowers and similarly-sized objects. We found stopping down quickly made out-of-focus areas appear a little chunky but lighting remained reasonably evenly rendered.
SPECS
Picture angle: 47 degrees
Minimum aperture: f/22
Lens construction: 9 elements in 7 groups (including 2 aspherical glass elements)
Lens mounts: Micro Four Thirds
Diaphragm Blades: 7 (circular aperture)
Focus drive: MSC compatible: high speed and silent AF
Stabilisation: No (Olympus cameras include body-integrated stabilisation)
Minimum focus: 25 cm
Maximum magnification: 0.12x (0.24x in 35mm format)
Filter size: 46 mm
Dimensions (Diameter x L): 57.8 x 42 mm
Weight: 137 grams
Supplied accessories: LC 46, LR-2 end cap, LH-49B lens hood, DR-49 Decoration Ring
TESTS
(Based on JPEG files from the Olympus OM-D E-M5.)
SAMPLES
Vignetting at f/1.8.
Rectilinear distortion.
ISO 200, 1/100 second at f/8.
Crop from the above image enlarged to 100% showing coloured fringing at contrast boundaries.
ISO 200, 1/1000 second at f/7.1.
ISO 400, 1/80 second at f/10.
ISO 200, 1/100 second at f/5.
Close-up of the same subject; ISO 200, 1/250 second at f/2.2.
Close-up at f/1.8; ISO 200, 1/4000 second at f/1.8.
Close up of the same subject at f/3.5; ISO 200, 1/2000 second at f/3.5.
Flare; ISO 200, 1/250 second at f/11.
ISO 200, 1/1600 second at f/9.
ISO 200, 1/80 second at f/8.
ISO 200, 1/13 second at f/9.
ISO 200, 1/250 second at f/13.
ISO 200, 1/2000 second at f/5.6.
ISO 400, 1/50 second at f/6.3.
ISO 200, 1/250 second at f/4.
Rating
RRP: AU$499; US$399
- Build: 8.8
- Handling: 8.5
- Image quality: 8.8
- Versatility: 8.5
