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The Olympus M.Zuiko 17mm f/2.8 is another pancake lens available for micro-four-thirds system cameras. The lens is either sold as part of a camera kit with the Olympus E-P1 or separately for about 260€/300US$. Its field-of-view is equivalent to about 34mm in full format terms so it’s a moderate wide-angle. Typical applications include landscape or street photography.

The M.Zuiko is even smaller than the already dwarfish Panasonic 20mm f/1.7 ASPH although this isn’t really all that surprising regarding its less ambitious max. aperture of f/2.8. Olympus is also "cheating" a little bit here because the lens (the inner lens tube to be precise) extends slightly into its working position upon power up. However, the procedure is not really noticeable and as such not objectionable. The build quality of the lens is perfectly fine – it is based on a quite high quality plastic body and a metal mount.

The AF uses a conventional micro motor. However, the AF speed is pretty reasonable and the accuracy is spot on (which is typical for contrast AF lenses). Manual focusing works "by wire" so there’s no direct mechanical coupling. This is sometimes controversially discussed by users but if you ask me it’s a non-issue. Unfortunately there’re no focus distance marks though.

Specifications

equiv. focal length (full format)
34mm

equiv. aperture (depth-of-field)
f/5.6

Optical construction
6 elements in 4 groups inc. 1x aspherical element

Number of aperture blades
5 (circular)

min. focus distance
0.2m (max. magnification ratio 1:9)

Dimensions
22x57mm

Weight
71g

Filter size
37mm (non-rotating)

Hood
-

Other features
-

Distortions

The M.Zuiko lens produces only a slight degree of barrel distortion (~0.8%) which is only rarely noticeable in field conditions. However, this is only a part of the truth. Micro-4/3 images are auto-corrected according to the stored lens profile (lens firmware) – this is done either by the camera directly (JPEG) or by the more popular RAW-converters a la Photoshop. The "untouched RAW" results (thus the principal capability of the lens) are much worse with a barrel distortion as bad as ~4.5% which is extreme (poor) for a prime lens.

Move your mouse cursor across the image to switch between the two variants (corrected/uncorrected RAW file).

Vignetting

Vignetting is not auto-corrected but it’s quite well controlled anyway. At f/2.8 the problem can be noticed in some field conditions but it’s nothing extreme either at ~0.8EV. The vignetting isn’t really field-relevant anymore from f/4 onwards.

<?XML:NAMESPACE PREFIX = [default] http://www.w3.org/2000/svg NS = "http://www.w3.org/2000/svg" />Vignettingat 17mm (corrected)f/2.8f/4f/5.6f/80.0EV0.3EV0.6EV0.9EV1.2EV1.5EVEV (f-stops)photozone.de

MTF (resolution)

The Olympus lens disappoints somewhat regarding its resolution capabilities. There’s nothing wrong whatsoever with the center quality which is generally on a very good level throughout the tested aperture range. However, the border quality is only good (till f/8). The extreme corners are very soft at f/2.8 and they do barely reach good levels around f/5.6.

The M.Zuiko seems to maintain a quite punchy contrast at close focus distances (unlike the Panasonic 20mm f/1.7).

Below is a simplified summary of the formal findings. The chart shows in line widths per picture height (LW/PH) which can be taken as a measure for sharpness. If you want to know more about the MTF50 figures you may check out the corresponding Imatest Explanations.

MTFat 17mmcenterborderextremef/2.8f/4f/5.6f/8f119901,3201,6501,9802,3102,640LW/PHphotozone.de

Chromatic Aberrations (CAs)

Lateral CAs are usually easy to correct during post-processing but for whatever reason this aspect is not auto-corrected. This is insofar surprising because the M.Zuiko has quite a problem here with an average CA pixel width of up to 3px at the borders. Let’s hope that this issue will be corrected via a firmware update soon because this is disturbing indeed.

Lateral CAspx width at 17mmf/2.8f/4f/5.6f/8f110.0px0.4px0.8px1.2px1.6px2.0px2.4px2.8pxaverage pixel width (border)photozone.de

Here’s a sample crop illustrating the problem:

Sample Images

Here’re a few sample images taken with the GF-1 and RAW-converted via Photoshop.

Click on a thumbnail to view the original file (opens in a separate window). Please note that the originals are FULL SIZE samples (=several megabytes) thus requiring a significant amount of bandwidth so please take care of the limited resources here.

Make
Panasonic

Model
DMC-GF1

ISO Speed
200

Focal Length
17.0mm

Aperture:
f/7.1

Exposure
1/400s

Make
Panasonic

Model
DMC-GF1

ISO Speed
200

Focal Length
17.0mm

Aperture:
f/6.3

Exposure
1/500s

Make
Panasonic

Model
DMC-GF1

ISO Speed
200

Focal Length
17.0mm

Aperture:
f/6.3

Exposure
1/1250s

Make
Panasonic

Model
DMC-GF1

ISO Speed
200

Focal Length
17.0mm

Aperture:
f/2.8

Exposure
1/4000s

Verdict

The Olympus M.Zuiko 17mm f/2.8 is a lovely little lens but unfortunately it does disappoint regarding its optical capabilities. You expect a top notch performance from a prime lens but the Zuiko isn’t overly sharp neither at max. aperture nor stopped down – the center quality is perfectly fine but the borders and corners are too soft in general. In principal the lens produces a hefty amount of barrel distortion. However, this problem is auto-corrected by the camera (or by the more popular RAW converters) so this is nothing to worry about from a user perspective. Surprisingly this is not the case with respect to lateral chromatic aberrations (CA) which are fairly extreme with a width of up to 3px at the image borders. The vignetting characteristic is pretty good when stopping down to f/4 and even at max. aperture it’s only visible in critical scenes. A nice aspect of the Zuiko is the quality of the bokeh (the out-of-focus blur) – it’s very smooth and out-of-focus highlights are rendered beautifully. However, all-in-all the lens leaves something to be desired.