Olympus OM Zuiko 28mm f/2.8

Introduction

Like its slightly slower cousin OM Zuiko 28mm f/3.5, the 28mm f/2.8 variant was manufactured by Olympus for its popular OM mount SLR system up until 2002. The OM mount was abandoned by Olympus in favor of the four thirds digital only format, however older OM type Zuiko lenses are still readily available on used markets and some models, particularly fast wide angle primes, are often highly sought after by photographers. The 28mm f/2.8 lens variant is commonly available on eBay as well as other online and retail used lens resellers, with good copies selling for about US$60 (as of September 2007).

The optical construction of the lens consists of 6 elements in 6 groups. The lens is very light and compact - measuring 32 x 60mm (1.2 x 2.3in) and weighs only 170g (6.1oz). The lens cam extends during focusing towards closeup, making the lens slightly loner. Together with its slower variant, the 28mm f/3.5, this is one of the smallest and lightest 28mm primes ever manufactured. The build construction is excellent (a common characteristic of OM Zuiko lenses) - the lens barrel as well as aperture ring are metal. The focusing ring is fully rubberized and is easy to grip. The minimum focusing distance is 30cm (11.8in) and the minimum aperture is f/22. The lens accepts 49mm screw-in type filters.

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 6 elements in 6 groups
Angular Field 75 degrees
Minimum Focus 30cm/11.8in
Focusing Action MF
f-stop Scale f/2.8-f/22, manual
Filter Size 49mm
Lens Hood N/A
Weight 170g/6.1oz
Dimensions 32x60mm/1.2x2.3"
Lens Case N/A

 

Field Tests

The lens showed pretty solid results in the field - center was quite sharp throughout the aperture range, however on a full-frame camera borders were visibly softer at wider aperture levels. Once stopped down to f/5.6 and beyond, the lens produced pretty sharp results across the entire frame.

 

Vignetting @ f/2.8 - full frame vs 1.6x crop
Vignetting @ f/2.8 - full frame vs 1.6x crop

The lens shows very noticeable vignetting on a full frame camera with wide open aperture. Vignetting is reduced significantly once stopped down to f/4 and by f/5.6 pretty much disappears. The lens shows insignificant amount of vignetting on an APS-C camera with wide open aperture. Unfortunately, like its slower f/3.5 variant, Olympus OM Zuiko 28mm f/2.8 fell prone to rather heavy color fringing at the widest aperture levels. Not counting the fringing, color reproduction was pretty accurate and the lens held its ground against flare.

 

ISO 100, 1/3200, f/2.8, 28mm (100% crop)
ISO 100, 1/3200, f/2.8, 28mm (100% crop)
Olympus OM Zuiko 28mm f/2.8 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: The lens demonstrated pretty decent overall results in the lab. Performance in the center was excellent straight from f/2.8. Border quality can be classified as decent at wider aperture levels and excellent from f/4 through f/11. The are no major fall-offs in quality across the frame and at its peak the lens is capable of producing excellent 16in and decent 24in prints - quite within a range of a good quality prime lens. Conclusion?

 

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 with wide open aperture, averaging ~1.4px, but falling to ~0.9px once stopped down to f/8 and beyond. CA in the center was slightly lower at f/2.8, averaging ~1px and dropping to very manageable 0.5px towards f/11.

 

Image borders @ 28mm (100% crop): f/2.8 vs f/8
Image borders @ 28mm (100% crop): f/2.8 vs f/8

 

Canon FF: Olympus OM Zuiko 28mm f/2.8 continued to show outstanding center performance on a full frame Canon 5D, but border quality suffered a little bit at wider aperture settings. At f/2.8 the lens shows rather average and not very impressive performance. Quality improves with stopped down aperture and by f/5.6 reached excellent levels. The lens shows most balanced results around f/8, where performance is top notch both in the center and around borders. Conclusion? No major surprises here - the lens gives up a bit of ground with wide apertures, but retains overall solid performance from f/5.6 through the rest of the aperture range. Not really striking results, but it certainly could have been worse.

 

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

 

Chromatic aberration still remains pretty high around borders even on a full frame body. f/2.8 suffered most, with CA often exceeding 1.2px. Center fared a bit better, where CA averaged ~0.7px at f/2. Chromatic aberration in the center is reduced as we stop down the aperture, reaching a quite manageable level of ~0.5px by f/8, however, CA around borders remains on a relatively high level, averaging ~1px throughout the rest of the aperture range.

 

Image borders @ 28mm (100% crop): f/2.8 vs f/8
Image borders @ 28mm (100% crop): f/2.8 vs f/8

 

Alternatives

As mentioned in my review of OM Zuiko 28mm f/3.5, Olympus used to manufacture three 28mm variants - OM Zuiko 28mm f/2.8 reviewed here, OM Zuiko 28mm f/3.5 (review) and OM Zuiko 28mm f/2. All three lenses exhibit similar characteristics within matching aperture range, so depending on your needs, you might opt for the fastest, slowest or middle-of-the-road variant. If you are willing to consider a slightly wider prime lens, Olympus can offer two more lenses in OM mount - 24mm f/2 and 24mm f/2.8. 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 5x more. You might also want to take a look at Asahi Pentax SMC Takumar  28mm f/3.5 or its faster cousing SMC Takumar 24mm f/3.5, both of which are commonly available and are fairly inexpensive.

 

Recommendation

Like its slower f/3.5 variant, Olympus OM Zuiko 28mm f/2.8 managed to show pretty solid overall performance - border quality at the widest aperture setting on a full frame body suffers a bit, but this has become a common characteristic for most wide angle lenses. Unfortunately, the lens suffers from rather higher then expected levels of color fringing at wide apertures, and this seems to be the only major weakness of this lens. Still, you might want to spend that $50-$60 to get one and try it for yourself - you will always be able to sell it later if you don't like it.