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Studio Tests

We've long praised the Olympus 50mm macro in our camera reviews as one of the sharpest lenses we've ever used, and true to form it turns in an exceptional performance in our studio tests. Even wide open it's an impressive performer in all regards, and things just get better on stopping down; there's simply very little to fault. Compared to the Sigma 50mm F1.4 EX DG HSM which will also be available in Four Thirds mount, it's distinctly sharper especially when stopped down a little (note that we tested the Sigma on the APS-C Canon EOS 450D, and the MTF50s on the more demanding Four Thirds sensor are expected to be approximately 13% lower).

Sharpness The lens is extremely sharp across the frame even wide open, and produces superb results from F2.8 though to F8, suggesting plenty in reserve for future higher resolution models. As usual on Four Thirds, F16-F22 are best avoided unless extreme depth of field is critical (which may well be the case for macro work).
Chromatic Aberration Lateral chromatic aberration is near-nonexistent at any aperture; the low measured levels will have little relevance in real-world use.
Falloff We consider falloff to start becoming a potential problem when the corner illumination falls to more than 1 stop below the centre. Falloff here measures a maximum of 0.7 stops wide open, which should be of no concern at all.
Distortion The 50mm macro is near-perfectly corrected for rectilinear distortion, with just a trivial amount of barrel distortion detectable.

Macro Focus

The 50mm F2.0 macro is optimized for close-up use, and so obviously does rather well in our macro test. The maximum magnification is 0.53x (giving an image size similar to a 1:1 macro lens on 35mm full-frame), with a measured closest focus of 23.5cm and a working distance of 10cm from the front of the lens to the subject.

Even at F2 sharpness is impressive right across the frame, distortion is negligible and there's no visible CA. Sharpness increases further on stopping down, and optimum results are obtained at about F6.3. Very impressive indeed.

(Click here for a macro test chart shot at F2.)
Macro - 33 x 25 mm coverage
Distortion: None
Corner softness: Extremely low
Focal length: 50mm (100mm equivalent)

Specific image quality issues

As always, our studio tests are backed up by taking hundreds of photographs with the lens across a range of subjects, and examining them in detail. This allows us to confirm our studio observations, and identify any other issues which don't show up in the tests. The 50mm F2.0 macro generally performs as well in the field as the studio tests would suggest, delivering exceptional image quality time after time except for a few specific circumstances.

Flare

Possibly the biggest weakness of this lens, the 50mm macro is distinctly unhappy with a strong light source in or near the frame. Place the sun in the frame, and it becomes surrounded by a broad and diffuse disk of halation, with an array of multicoloured flare patterns which become more clearly defined on stopping down. Move the sun slightly out of the frame and the lens becomes afflicted by high levels of veiling flare. To be fair this kind of behaviour isn't particularly unusual for telephoto lenses with relatively complex optical designs, but it does mean the 50mm F2 may not necessarily be the ideal choice for photographing sunsets.

1/6400 sec F2, Olympus E-3 1/400 sec F8, Olympus E-3
1/60 sec F22, Olympus E-3 1/800 sec F2, Olympus E-3

Background blur ('bokeh')

One genuinely desirable, but difficult to measure aspect of a lens's performance is the ability to deliver smoothly blurred out-of-focus regions when trying to isolate a subject from the background, generally when using a long focal length and large aperture. And for Four Thirds users looking to attain a degree of subject isolation from the background (not usually a strong point of the format), the 50mm F2 Macro is one of the best options available, although some users may still find its selective focus capabilities somewhat limiting when compared to fast primes used on larger formats.

The lens generally delivers smooth and attractive bokeh across the full range of subject distances, with none of the harsh edging to out-of-focus highlights often seen with distant backgrounds. The only real issue is with bokeh chromatic aberration, which is covered in more detail below.

1/320 sec F2.8, ISO 100 50% crop
1/2500 sec F2.8, ISO 100 50% crop

Chromatic aberration

Lateral chromatic aberration is essentially negligible with this lens, however as is common with fast primes, 'bokeh' CAs (coloured fringing around high-contrast regions outside of the field of focus) can be quite noticeable when viewing the image files at the pixel level. With this lens, it takes the form of fairly intense magenta fringing in front of the field of focus, and green fringing behind, which persists across all focus distances, but disappears progressively on stopping down. However unlike lateral CA it can be difficult if not impossible to remove completely in software, although a regionally-applied colour-specific desaturation command in Photoshop will often do the trick.

Olympus E-3, 1/1000 sec F2.0
Olympus E-3, 1/20 sec F2.0
100% crop, in front of focal plane 100% crop, in front of focal plane
100% crop, behind focal plane 100% crop, behind focal plane

 

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