SLRgear Review

November 04, 2016

by Andrew Alexander

Olympus announced its first 25mm prime lens for Micro Four Thirds mirrorless cameras back in 2014 with the lightweight 25mm ƒ/1.8 lens, a classic 50mm (eq.) focal length with a decently bright ƒ/1.8 aperture. But, if that isn't fast enough for you though, a new option is now available -- the 25mm ƒ/1.2 Pro M.Zuiko Digital.

The 25mm ƒ/1.2 Pro, one of the newest additions to their growing professional-grade Zuiko Pro line, offers the fastest aperture available in any Olympus lens so far. However, at a sticker price of US$1,199, it's definitely available at a premium. The price tag is justified by the impressive amount of glass making up the lens -- 19 elements in 14 groups, including 1 aspherical, 1 SED, 2 ED, 1 E-HR, and 3 HR elements.

The lens is available now, accepts 62mm filters, and ships with a round lens hood.

Sharpness

The lens does not disappoint: it is very sharp right out of the gate at ƒ/1.2 and offers tack-sharp edge-to-edge sharpness by ƒ/2. You can stop down further if you want, but it doesn't garner substantially more image sharpness. Olympus has figured it out -- this is a lens that people will buy to shoot at ƒ/1.2, and you get your money's worth in that regard.

Diffraction limiting starts to set in at ƒ/11, but you'd be hard-pressed to notice it -- at ƒ/16, you may note a slight generalized softness, but then, at ƒ/16 this lens performs about as well as some lenses do at their best settings.

Chromatic Aberration

There is a slight amount of chromatic aberration to deal with, but it's mostly present at wider apertures and in the corners: there is a very slight amount of magenta fringing in areas of high contrast.

Shading (''Vignetting'')

As you'd expect with fast primes, there is some corner shading evident when using the lens at its widest apertures. In this case, at ƒ/1.2, the extreme corners of an image shot with this lens are about 2/3 of a stop darker than the center of the image. Stopping down reduces the amount of corner shading, and by ƒ/2 and smaller, the corners are a quarter-stop darker or less.

Distortion

There is a very small amount of pincushion distortion evident on images shot with this lens -- nothing that a light amount of correction in any post-processing program couldn't take care of.

Autofocus Operation

The Olympus 25mm ƒ/1.2 uses their MSC (Move-Still-Compatible) technology, making the lens fast and near-silent to autofocus; the lens focuses between close-focus and infinity in less than a second, and short changes in focus happen almost instantly.

Since focusing is an electronic fly-by-wire system, autofocus results can only be overridden on Olympus bodies by setting the focusing mode on the camera to "S-AF + MF" mode and rotating the focus ring at any time. Rotating the focus ring in normal S-AF (single-shot AF) mode does not change focus. Of course, full-time manual focus is also available, either by pulling back on the focus ring or by selecting Manual Focus mode in the camera menu.

The lens is completely internally focusing, and during AF, the front element does not extend or rotate, making accessories such as circular polarizers easy to use with this lens.

Macro

The lens is not designed for true macro photography with a only a 0.11x magnification factor. However, with a minimum focusing distance of just 30cm (around 12 inches), the Olympus 25mm ƒ/1.2 provides good close-focusing performance for a 50mm equivalent prime.

Build Quality and Handling

The Olympus 25mm ƒ/1.2 M.Zuiko looks and feels like a premium offering, with a design that's in-line with other Zuiko Pro lenses. The sleek metal body feels very solid and well-built with a fully weather-sealed construction like the other 'Pro' models, and includes a gasket seal around the lens mount.

Despite being a Micro Four Thirds lens, it's fairly big and somewhat heavier than we're used to for a MFT prime, weighing in at around 14.5 oz. It is a natural fit, though, with the larger bodies like the EM-1 Mark II, but is a bit heavy for the smaller Micro Four Thirds cameras. The lens uses a complex design: 19 elements in 14 groups. The diaphragm features 9 rounded blades to provide very pleasing out-of-focus results.

Other than the focus ring with characteristic push-pull clutch mechanism for AF/MF switching, there is only a single button, the "L-Fn" button, which allows the user to program a function for instant access. Otherwise, all lens functions are controlled by the camera. There is a very nice distance and depth-of-field scale, which is exposed when the lens is placed into manual focus mode.

The focusing ring is plastic with raised ribs, about 1 1/4 inches wide, and has a nice tactile feel to it. Since Olympus Micro Four Thirds cameras use a fly-by-wire system, the focusing ring will turn forever in either direction while the ring is in 'AF' position. However, when pulled back for manual focus mode, the focus ring does feature hard stops.

The Olympus 25mm ƒ/1.2 M.Zuiko accepts the LH-66B lens hood. This round hood is ribbed on the interior, and reverses to attach to the lens for storage. It is 1.5 inches long.

Alternatives

Olympus 25mm ƒ/1.8 M.Zuiko Digital ~$400

If you'd like to stay in the Olympus camp but don't want to spend $1,200, this lens is available at a third of the cost, however you're giving up a full stop of light-gathering ability. Optical performance is very similar, though there are a few practical items that are also not present in this lens, such as the L-Fn function button and weather-sealing.

Panasonic 25mm ƒ/1.4 ASPH LEICA DG SUMMILUX ~$600

Panasonic also offers a fast prime in the 25mm focal length, and it performs exceptionally well. For half the price you're only giving up 1/3 of a stop, but like the Olympus above, you're also giving up some fit and finish.

Panasonic 25mm ƒ/1.7 ASPH LUMIX G ~$250

The least expensive way to get into the 25mm category for Micro Four Thirds, the Panasonic 25mm ƒ/1.7 performs extremely well, and is the most economical.

Conclusion

This is a premium lens that yields exquisite results. It may have a premium price, as well, but fortunately, it's worth every penny, providing optical performance worthy of the price tag. Generally, you know if you need a lens with this huge aperture size, and it's not for the faint of heart. At ƒ/1.2, the depth of field is razor-thin and the results are fantastic. Shooting at ƒ/1.2 demands a strict technique, but the resulting images are worth it.

Product Photos

Gallery Images

Sample Photos

The VFA target should give you a good idea of sharpness in the center and corners, as well as some idea of the extent of barrel or pincushion distortion and chromatic aberration, while the Still Life subject may help in judging contrast and color. We shoot both images using the default JPEG settings and manual white balance of our test bodies, so the images should be quite consistent from lens to lens.

As appropriate, we shoot these with both full-frame and sub-frame bodies, at a range of focal lengths, and at both maximum aperture and ƒ/8. For the ''VFA'' target (the viewfinder accuracy target from Imaging Resource), we also provide sample crops from the center and upper-left corner of each shot, so you can quickly get a sense of relative sharpness, without having to download and inspect the full-res images. To avoid space limitations with the layout of our review pages, indexes to the test shots launch in separate windows.