Olympus OM Zuiko 28mm f/3.5

Introduction

Olympus OM Zuiko 28mm f/3.5, which was manufactured by Olympus for its very popular OM SLR system up until 2002, is one of three wide angle 28mm prime lenses offered for that system. Olympus abandoned OM system in favor of its new four-thirds digital SLR platform, but the OM type lenses are readily available on used markets like eBay and some models, particularly fast wide angle lenses, are still sought after by many photographers. The 28mm f/3.5 lens  variant is one of the most commonly available OM lenses and is one of the most inexpensive ones too, with good copies fetching about US$35 (as of September 2007).

The optical construction of the lens consists of 7 elements in 7 groups. It is believed that Olympus used to manufacture this 28mm lens variant in both single-coated as well as multi-coated formats. Unfortunately, there does not seem to be a way to determine whether a lens is single or multi coated without knowing at what serial number Olympus switched production from single to multi coating. The build construction is superb - the lens barrel is metal, as is the aperture ring, which is located at the front of the lens barrel. The focusing ring is fully rubberized.

Olympus OM Zuiko 28mm f/3.5 is probably one of the smallest wide angle SLR lenses ever manufactured  - it measures only 31 x 59mm (1.2 x 2.3in) and weighs only 180g (6.3oz). The lens cam extends during focusing towards closeup, adding another 10mm or so the the total length of the lens. The minimum focusing distance is 30cm (11.8in) and the minimum aperture is f/16. The filter size is 49mm.

Image

On APS-C cameras with 1.6x crop factor like Digital Rebel XTi, the lens has a field of view similar to that of a 45mm lens on a full-frame body. To use the lens on a Canon EOS body I used a generic, non AF-chipped Fotodiox Olympus OM to EOS adapter. you will end up operating the camera in manual or aperture priority modes with all but center weighted metering disabled.

 

Summary
Lens Composition 7 elements in 7 groups
Angular Field 75 degrees
Minimum Focus 30cm/11.8in
Focusing Action MF
f-stop Scale f/3.5-f/16, manual
Filter Size 49mm
Lens Hood N/A
Weight 180g/6.3oz
Dimensions 31x59mm/1.2x2.3"
Lens Case N/A

 

Field Tests

For a sub-$40 lens, Olympus OM 28mm f/3.5 was full of surprises - the lens was tack sharp in the center across the entire tested aperture range. Border quality matched the center, except at f/3.5 where the lens seemed to produce slightly softer results on a full frame body.

 

Vignetting @ f/3.5 - full frame vs 1.6x crop
Vignetting @ f/3.5 - full frame vs 1.6x crop

The lens showed insignificant amount of vignetting on a full frame Canon 5D with wide open aperture. Vignetting is non-existent on an APS-C camera straight from f/3.5. The results are not very surprising considering the lens is relatively slow. The color reproduction was pretty accurate, however, the lens showed somewhat higher levels of color fringing at f/3.5. On the other hand, the lens held its ground well against flare and distortion.

 

ISO 100, 1/2000, f/3.5, 28mm (100% crop)
ISO 100, 1/2000, f/3.5, 28mm (100% crop)
Olympus OM Zuiko 28mm f/3.5 image gallery... (coming soon)

 

Lab Tests

Please note that MTF50 results for APS-C and Full-Frame cameras are not cross-comparable despite the same normalized [0:1] range used to report results for both types of cameras.

 

Four Thirds: Coming soon...

 

Canon APS-C: Olympus OM Zuiko 28mm f/3.5 produced very solid results in the lab, with excellent center performance throughout the aperture range and equally good border performance. Overall performance is distributed evenly across the frame, which is obviously a major plus for any lens. At its peak, the lens is capable of producing outstanding 16in and decent 24in prints. Conclusion? The lens clearly benefits from a relatively small maximum aperture but while the lens does not show the best absolute results, it demonstrates pretty solid overall performance and will be suitable for most applications.

 

MTF50 (Line Width/Inch on the Print) @ 28mm
MTF50 (Line Width/Inch on the Print) @ 28mm

 

Normalized raw MTF50 @ 28mm
Normalized raw MTF50 @ 28mm

 

Chromatic aberration was rather high around borders on an APC-C body - at f/3.5 it exceeded 1.7px and remained on a somewhat high level through the rest of the aperture, averaging ~1.1px even at f/11. CA in the center was slightly lower, averaging ~1px at f/3.5 and dropping to ~0.5px with aperture stopped down to f/11.

 

Image borders @ 28mm (100% crop): f/3.5 vs f/8
Image borders @ 28mm (100% crop): f/3.5 vs f/8

 

Canon FF: OM Zuiko 28mm f/3.5 demonstrated equally excellent center performance on a full frame Canon 5D. Center is tack sharp straight from f/3.5. Border performance suffered a little bit and the lens gave up ground at f/3.5 where results are rather average. Performance improves with stopped down aperture and by f/5.6 border quality is almost on par with the center. Conclusion? Border performance at f/3.5 is somewhat disappointing, especially considering that f/3.5 is a relatively slow aperture, however, overall results are still pretty solid for such a compact (and cheap) wide angle prime.

 

Normalized raw MTF50 @ 28mm
Normalized raw MTF50 @ 28mm

 

The lens fared slightly better on a full frame body, with CA averaging ~1.3px around borders at f/3.5 and dropping to ~0.7px by f/11. Center fared even better - CA there did not exceed 1px with wide open aperture and once stopped down to f/8 practically disappeared.

 

Image borders @ 28mm (100% crop): f/3.5 vs f/8
Image borders @ 28mm (100% crop): f/3.5 vs f/8

 

Alternatives

As mentioned earlier, Olympus used to manufacture two other 28mm variants - OM Zuiko 28mm f/2.8 (review) and OM Zuiko 28mm f/2 . The 28mm f/2.8 variant is as common as the f/3.5 version and is as affordable (going rate is ~US$60 on eBay), while its slightly faster version 28mm f/2 is more rare and fetches about US$250-$350. All three lenses showcase similar performance in the overlapping aperture range, so if you don't care about extra speed, then there's probably no reason to favor one over the other. Outside of the Olympus OM mount, Carl Zeiss Distagon T* 28mm f/2.8 in Contax/Yashica mount (reviwe) produces outstanding image quality, but also costs 5-6 times more. Finally Leica's Elmarit R 28mm f/2.8 offers superb image quality matched by superb build quality. However, it's been reported that the latest ROM revision of the Elmarit R 28mm f/2.8 has mirror clearance issues with Canon's 5D, hence it might not be suitable to everyone.

 

Recommendation

Olympus OM Zuiko 2mm f/3.5 is not the fastest 28mm prime available on the market. However, it is easily one of the most compact and inexpensive ones. Match that with a solid overall performance and excellent build quality, and suddenly the overall package becomes pretty attractive. C'mon, for a $35 lens, Zuiko 28mm is full of surprises and as long as you don't need a super fast lens and can live with somewhat higher level of chromatic aberration, you would be hard pressed to find a better bargain.