Olympus M.Zuiko Digital ED 8-25mm f/4.0 PRO lens

      Photo Review 9.0

      In summary

      The combination of compact size, relatively light weight and excellent performance and usability make the M.Zuiko Digital ED 8-25mm f/4.0 PRO lens a worthy contender for a place in M4/3 camera users’ kitbags.


      Full review

      Announced in early June, the M.Zuiko Digital ED 8-25mm f/4.0 PRO is a lightweight wide-angle zoom lens for M4/3 cameras that covers a focal length range equivalent to 16-50mm in 35mm format. Weighing only 411 grams, it has a constant f/4 maximum aperture and minimum focusing distance of 23 cm across the entire zoom range. It also features a Manual Focus Clutch for instant switching between auto and manual focusing plus a L-Fn (lens function) button that can be programmed to allow easy switching of a selected camera function. Despite the wide angle of view, this lens accepts 72 mm filters. It also comes with a petal-shaped lens hood.

      Angled view of the M.Zuiko Digital ED 8-25mm f/4.0 PRO lens. (Source: OM Digital Solutions.)

      The optical design of this lens (shown below) is complex and comprises 16 elements in 10 groups. Among them are a large DSA, which was included to significantly reduce sagittal comatic aberration. Also present are two aspherical ED (Extra-low Dispersion) and one each of Super ED, ED, Super HR (high refractive index), HR and HD (High Definition) elements.

      This illustration shows the positions of the exotic elements in the design of the M.Zuiko Digital ED 8-25mm f/4.0 PRO lens

      ZERO Coating is used to suppress ghosting and flare while shooting backlit subjects. Splashproof, dustproof and freezeproof construction makes it usable in demanding environments including rain and snow. In addition, the front element is fluorine coated to repel moisture and dust and make the lens easy to keep clean.

      This diagram shows the extent of the weather-resistant sealing in the M.Zuiko Digital ED 8-25mm f/4.0 PRO lens. (Source: OM Digital Solutions.)

      Who’s it For?
      The new 8-25mm f/4.0 PRO lens isn’t the fastest wide-angle zoom lens in the Olympus line-up; nor does it provide the widest angle-of-view coverage. Both honours go to the M.Zuiko Digital ED 7-14mm f/2.8 PRO lens, which we reviewed back in June 2015.

      The viewing angles of this lens (equivalent to a 16-50mm lens on a 35mm camera) make it more versatile than the 7-14mm lens. It’s also a bit smaller and lighter so it’s a better choice for travellers and its retracting mechanism means it won’t take up unnecessary space in a camera bag.

      The 8-25mm zoom range is wide enough at 8mm to be useful for landscapes and some architectural photography, while the 50mm position can be used for portraits, street shooting and casual snapshots. Reliable dust-, splash- and freeze-proof sealing makes it usable in challenging outdoor conditions, while the fluorine costing on the front element makes it easy to keep free of water droplets, grease and dust.

      With a minimum focus of 23 cm across the full zoom range, this lens provides excellent versatility for shooting close-ups, allowing flexibility in subject size and perspective. At the maximum magnification of 0.42x, users can achieve close to half-life size reproduction.

      Like all Olympus M.Zuiko Pro lenses, this lens is very well built. But it’s not stabilised, which isn’t an issue with OM-D cameras, which come with sensor-shift stabilisation. However, photographers who want to use this lens on a Panasonic G-series body will need a model with built-in O.I.S.

      Build and Ergonomics
      The build quality of this lens is similar to other M.Zuiko PRO lenses: sturdy but highly refined with an elegant low-gloss black finish and a very solid metal mounting plate.  The outer barrel, which carries the main control surfaces, must be rotated to the 8mm position before the lens can be used. This extends the overall length of the lens by 25 mm and exposes the inner barrel.

      At the front of the outer barrel, the Manual Focus Clutch mechanism, a feature in many M.Zuiko PRO series lenses, provides easy switching between auto and manual focusing; push the focusing ring forwards for autofocusing and pull it back to engage manual focus. The focusing ring is 11 mm wide in the AF position, where it can be rotated through 360 degrees. Pulling it back to the MF position exposes a 5 mm wide distance scale, marked in metres and feet that ranges from 0.23 metres to infinity.

      Immediately behind the focusing ring is a 26 mm wide zoom ring, which is linked to the inner barrel. It carries four narrow bands of ribbing to provide a grip surface and ends in an un-ribbed band that is 5 mm wide and carries stamped markings for the 8mm, 10mm, 14mm, 18mm and 25mm positions.

      The inner barrel extends furthest at the 8mm position and retracts to about 16 mm when the lens is zoomed in to 18mm before easing out a little at 25mm. The front of the lens doesn’t rotate during focusing and zooming.

      Just behind the zoom ring is a 16 mm wide fixed section of the outer barrel which slopes slightly inwards about half way across its width. Branding information (the name of the lens is stamped in white on this section, with the Lens-Function (L-Fn) button around the side of the barrel to the left.

      This button can be programmed in the camera’s menu to control a single function, making it instantly available when the button is pressed. Options include focus peaking, AF stop, AE/AF lock, depth-of-field preview, one-touch WB, AF area select and Home, MF selection, RAW+JPEG/JPEG selection, Test Picture, exposure compensation, Live Guide, Digital Teleconverter, Keystone compensation, HDR, bracketing, ISO, WB, level display, EVF display modes and magnify.

      The lens ends in a solid metal mounting plate, which is chromed for durability. A line of 11 gold-plated contacts enables signals to pass between the camera and lens. The front of the lens is threaded to accept 72 mm filters.

      The lens is supplied with a petal-shaped hood made from hard black plastic, which attaches to the bayonet mounting at the front of the lens with a very solid click, thanks to a locking button.  This button must be pressed when removing the hood, which reverses onto the lens for storage.

      Our test images and sample shots were captured with the lens on the OM-D E-M1 Mark II body. Unfortunately, our area in Sydney was still in hard lockdown during the time we had the lens so our options for taking sample shots were limited.

      Imatest testing confirmed the lens was capable of exceeding expectations for the camera’s sensor at a number of focal length and aperture settings, particularly in the centre of the frame. Measurements at roughly half way out to the periphery fell a little short with JPEGs, although less so with raw files. Three quarters of the way out from the centre, even raw files fell slightly below expectations for the camera’s 20-megapixel sensor.

      Interestingly, the highest JPEG resolution we measures was at f/4 (the maximum aperture) with the 18mm focal length. But most raw files scored above expectations results across a wide range of aperture settings in both the centre of the frame and half way out, indicating above-average performance. The graph below shows the results of our tests.

      Lateral chromatic aberration remained within the ‘negligible’ band for all but one of aperture settings and that was f/4 at 8mm. This performance was paralleled in both JPEGs and raw files and is shown in the graph of our test results below.  The red line marks the boundary between ‘negligible’ and ‘low’ CA.

      Because in-camera corrections are applied for both vignetting and rectilinear distortion, we had to use ORF.RAW files to see whether they were present. Vignetting was barely noticeable at the f/4 maximum aperture at all focal length settings, although we found traces of corner darkening at 8mm. Essentially, it’s not an issue with this lens.

      Rectilinear distortion was typical of many zoom lenses with noticeable barrel distortion at the 8mm focal length, which reduced to virtually no distortion at 18mm and slight pincushioning at 25mm. Because this distortion is automatically corrected in-camera and when converting raw files into editable formats, it’s a very minor issue.

      Autofocusing performance, which is influenced by the algorithms in the camera, was hard to fault, even with fast-moving subjects. The seven-bladed lens diaphragm captured nice, 14-pointed sunstars at f/22 when the camera was pointed directly at a bright light source. Some interesting coloured artefacts were associated with them, especially with the 25mm focal length setting.

      Bokeh was reasonably smooth at f/4, particularly at the 25mm focal length. We found slight outlining in bright background highlights but otherwise background blurring was acceptably smooth for f/4 with a M4/3 camera.


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      Picture angle: 107 to 47 degrees  (16-50mm in 35mm format)
      Minimum aperture:  f/22
      Lens construction:16 elements in 10 groups (including 1 DSA, two aspherical ED, 1 Super ED, 1 ED, 1 Super HR, 1 HR and 1 HD elements)
      Lens mounts: Micro Four Thirds
      Diaphragm Blades: 7 (circular aperture)
      Weather resistance: IEC Standard publication 60529 IPX1 / Dustproof construction
      Focus drive: Linear motor (High-speed Imager AF / MSC)
      Stabilisation: No (relies on IBIS in camera)
      Minimum focus: 23 cm (throughout the zoom range)
      Maximum magnification: Wide: 0.07x / Tele: 0.21x
      Filter size: 72 mm
      Dimensions (Diameter x L):72 x 88.5 mm
      Weight:411  grams
      Standard Accessories: LC-72C Lens Cap, LR-2 Lens Rear Cap, LH-76E Lens Hood, CS-53 Wrapping Cloth, Instruction Manual, Olympus Local Warranty Card
      Distributor: OM Digital Solutions Australia, 1300 659 678



      Based upon JPEG files captured with the lens on the OM-D E-M1 II  camera body.

      Based on ORF.RAW files recorded simultaneously with the JPEGs and converted into 16-bit TIFF format with Adobe Camera Raw.


      Vignetting at 8mm f/4.

      Vignetting at 10mm f/4.

      Vignetting at 14mm f/4.

      Vignetting at 18mm f/4.

      Vignetting at 25mm f/4.

      Uncorrected rectilinear distortion at 8mm.

      Uncorrected rectilinear distortion at 10mm.

      Uncorrected rectilinear distortion at 14mm.

      Uncorrected rectilinear distortion at 18mm.

      Uncorrected rectilinear distortion at 25mm.

      8mm focal length, ISO 200, 1/80 second at f/11.

      Crop from the above image magnified to 100% showing minimal edge softening and fringing.

      10mm focal length, ISO 200, 1/100 second at f/13.

      14mm focal length, ISO 200, 1/100 second at f/13.

      18mm focal length, ISO 200, 1/100 second at f/13.

      25mm focal length, ISO 200, 1/100 second at f/13.

      Close-up at 8mm
      focal length; ISO 200, 1/1250 second at f/4.

      Close-up at 25mm
      focal length; ISO 200, 1/1600 second at f/4.

      Close-up at15mm focal length; ISO 200, 1/200 second at f/7.1.

      25mm focal length, ISO 200, 1/320 second at f/9.

      8mm focal length, ISO 200, 1/250 second at f/8.

      14mm focal length, ISO 200, 1/125 second at f/5.6.

      25mm focal length, ISO 200, 1/320 second at f/9.

      25mm focal length, ISO 200, 1/320 second at f/10.

      Crop from the above image magnified to 100%.

      22mm focal length, ISO 200, 1/100 second at f/5.

      8mm focal length, ISO 200, 1/125second at f/5.6.

      Backlit scene; 25mm focal length, ISO 200, 1/60 second at f/16.

      15mm focal length, ISO 200, 1/8 second at f/8.

      25mm focal length, ISO 200, 1/250 second at f/8.

      Sunstar at 8mm focal length; ISO 200, 1/20 second at f/22.

      Sunstar at 14mm focal length; ISO 200, 1/20 second at f/22.

      Sunstar at 25mm focal length; ISO 200, 1/20 second at f/22.

      25mm focal length, ISO 200, 1/30 second at f/10.



      RRP: AU$1599; US$1099.99 (ex tax)

      • Build: 9.0
      • Handling: 8.9
      • Image quality: 8.9
      • Autofocusing: 9.0
      • Versatility: 8.9