Olympus M. Zuiko Digital ED 8-25mm f/4 Pro Review

The Olympus M. Zuiko Digital ED 8-25mm f/4 Pro is a wide-angle zoom lens for use on Micro Four Thirds mirrorless cameras. Its Pro status means that it’s  designed to a high standard and it’s weatherproof so you don’t need to worry if it starts to rain when you’re out on a shoot.

On a Micro Four Thirds camera such as the Olympus OM-D E-M1 III, OM-D E-M5 III or Panasonic G9, the M. Zuiko Digital ED 8-25mm f/4 Pro has an effective focal length of 16-50mm, making it suitable for landscape and cityscape photography.

The M. Zuiko Digital ED 8-25mm f/4 Pro is the first of Olympus’s Pro lenses to feature a collapsible barrel that enables the optic to be reduced in size (by about 2cm) when it’s not in use. This means that the zoom ring needs to be rotated from the stop point to at least the 8mm point to extend it ready for use. Then, after shooting, the ring can be rotated clockwise (as you hold the camera) beyond the 8mm point to collapse the barrel.

Despite this design, the Olympus 8-25mm f/4 Pro is weather-sealed to a rating of IPX-1 and is freeze-proof down to 10°C, which is great news for anyone who likes shooting in harsh conditions.

Inside the barrel, there are 16 elements arranged in 10 groups with two aspherical elements, one double-sided aspherical (DSA) element, a Super ED (extra-low dispersion) element and a High Refractive index (HR) element. The HR element helps to keep the size of the lens down, while the Super ED element is designed to make light of different colours focus at the same point so that chromatic aberration is minimised. Meanwhile, the aspherical elements help maintain sharpness across the whole image.

As usual, the aperture is rounded, however, it is only made up of 7 blades, 9 seems more common these days.

In a key distinguishing feature from the Olympus M. Zuiko Digital ED 7-14mm f/2.8 Pro, which has a very bulbous front element, the 8-25mm f/4 Pro has a filter thread and can accept standard 72mm screw-in filters. Alternatively, you can mount a filter holder such as the Kase K9 system to enable rectangular filters to be used.

Olympus has managed to give the 8-25mm f/4 Pro a closest focusing distance of 23cm throughout its zoom range, and it gives a maximum magnification of 0.42x in 35mm terms.

As you’d expect with a lens in the Olympus Pro range, the M. Zuiko Digital ED 8-25mm f/4 Pro feels fairly solid and robust, but at 411g, it’s not too heavy. It also has a metal mount with a rubber gasket around it to keep out dust and moisture.

I tested the 8-25mm f/4 Pro on the Olympus OM-D E-M1 Mark II and, thanks to the camera’s deep grip, it feels nicely at home.

While the action of the zoom and manual focus ring isn’t quite as smooth as that of some other recent lenses that I’ve tested, it’s nice to discover that there are physical endpoints to the focusing movement. It’s also possible to switch quickly between manual and automatic focusing by pushing the focus ring forwards or backwards along the barrel.

A manual focusing distance scale is revealed when the ring is pulled back, which is handy if you want to preset the focus or focus at a specific distance.

There are two ‘MF Assist’ options in the E-M1 II’s menu, ‘Magnify’ and ‘Peaking’. If Magnify is activated, the area under the selected AF point enlarges as soon as the manual focus ring is rotated. It’s also possible to set the focus ring to operate when the lens is set to AF, which could be handy on occasion.

I like the manual focus clutch mechanism, but it can be activated accidentally quite easily. If you find this happens a lot, or you just don’t get on with it, the clutch can be de-activated via the camera’s menu.

On the left of the barrel, towards the lens mount, there’s an L-Fn (lens function) button that is set to AF-stop by default, but it can be assigned one of a long list of features.

Mounted on the OM-D E-M1 Mark II, the M. Zuiko Digital ED 8-25mm f/4 Pro focuses quickly and silently. Even in low light, I didn’t need to switch to manual focusing as the camera and lens did their job well.

It’s also good to see that focus breathing is controlled very well so that the framing doesn’t change noticeably as the focus distance is adjusted.

Impressively, the M. Zuiko Digital ED 8-25mm f/4 Pro keeps curvilinear distortion under control very well. I was expecting to see significant bowing of straight lines at the 8mm end, but it’s actually very subtle. It gets a bit more noticeable with very close subjects, but it’s not a major concern by any means.

I’m also very happy with the level of sharpness throughout the focal length range, across the frame and through most of the aperture range. If you’re shooting at the 8mm point, it’s worth closing down to f/5.6, but the results are still very good at f/4.

At the 10mm point, the difference in sharpness between f/4 and f/5.6 is less pronounced, and at 14mm, 18mm and 25mm, the sharpness is excellent from f4 to f/11.  There’s a slight softening of details at f/16 through the whole focal length range, and f/22 is probably best avoided. However, given the depth of field that is captured with such a wide lens on a Micro Four Thirds camera, it’s unlikely that the smallest aperture will be required frequently.

Even when the aperture is at its widest, vignetting is controlled very well. If you swap quickly between images of the same scene shot at different apertures, you may see the corners brighten very slightly as the aperture closes to f/5.6 and f/8, but it’s so mild it’s not worth worrying about.

As you’d expect, if you include the sun in the frame, you’re likely to get some flare, but it’s not bad and the M. Zuiko Digital ED 8-25mm f/4 Pro doesn’t seem especially prone to it.

Further good news is that chromatic aberration is get in check extremely well so that coloured fringing is very unlikely to be problematic in your images.

If you shoot a close subject with the aperture fully open, it’s possible to blur the background nicely with the 8-25mm f/4 Pro and small highlights are attractively rendered.

Follow the link to browse and download full resolution images shot using the Olympus M. Zuiko Digital ED 8-25mm f/4 Pro.

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I’m a fan of wide-angle photography and the Olympus M. Zuiko Digital ED 7-14mm f/2.8 Pro is a lens I have enjoyed using on many occasions. However, the M. Zuiko Digital ED 8-25mm f/4 Pro is 123g lighter and more versatile. Granted, you lose 1mm (effectively 2mm) at the widest point and a whole stop in the aperture, but you gain the ability to use normal filters without an adapter, and there’s more reach at the longer end.

Provided you avoided the smallest aperture settings, the image quality is also superb with plenty of sharp detail across the frame and the optical flaws are minimal.