The Zuiko 28-48 f4 on A Sony A7R

This is an article about a little known lens (at least based on internet searches) from the OM Zuiko film era which I’ve always been curious about, the diminutive 28-48 f4. I bought this one on Ebay for around £80 to see how well it would perform against the much larger (and excellent) Sony FE 24-105 f4 and was lucky enough to fine one with the original rubber lens hood.

MIR has an excellent summary of this lens here :-

On the A7R with a Rayqual adaptor
And how it was meant to look on an OM2N. I prefer this look personally!

Olympus’s only wide angle zoom for the OM series, it was made in the 80’s and looks multi coated (mine doesn’t have a MC designation). It has 8 elements in 8 groups and has a quality feel to it. It’s a typically small OM lens, weighing a light 300g or 10ish ounces, the aperture range is f4 to f22 the filter size (common across many OM Zuikos) is 49mm, and the minimum focus distance is 65cm or about 2 ft. A pretty modest spec by modern standards, my impression is that Olympus was quite conservative in keeping it’s specification modest to keep size and weight to a minimum, and maintain good performance across the short zoom range.

Typically small and light, the usual Zuiko OM quality build feel.

For those not familiar with using old film lenses on digital, there is no image stabilisation, no communication between lens and camera, so no auto corrections in software, you’re on your own in correcting any lens faults. The lens produces images ‘as is’ and can’t rely on software to sort things out in post processing (apart from some general corrections such as CA when your software can detect it).

Straight RAW conversion, 35mm f8. This is Worbarrow bay BTW.
The memorial to William Barnes, the Dorset dialect poet in Dorchester. Nice contrast and good resolution at 48mm f8.
Enlargement from the above shot.

Initial impressions are very favourable. On the A7R it balances beautifully (it’s very good on an OM2N as well) making a lightweight, compact and versatile combination – at least it’s versatile for someone used to using a 50mm lens most of the time. The focus ring covers infinity to minimum focus distance in around 90 degrees making for snappy focussing and as the lens appears to be very sharp through the viewfinder, manual focus with focus magnify is positive. A real pleasure to use. But I do like Zuiko lenses!

So far so good for the physical description, what about all that sharpness, flare, bokeh, chromatic aberration and distortion stuff?So, some initial shots at f4 across the zoom range.

Vignetting is quite significant at 28mm, easing through 35mm to be less noticeable by 48mm. It’s pretty much gone one stop down at 5.6 and not visible at f8. All easily correctable in your software of choice.


Distortion – A moderate barrel distortion at 28mm, none by 35mm.

Chromatic aberration is minimal. A little purple fringing wide open, worst at the 28mm end, and some red CA off bright elements of an image, all easily correctable.

From this shot at 28mm :-
A few pixels of red CA off the bright edge. Easily correctable.

Flare. This is quite an old lens from an era where zooms were difficult to design and seen as a nasty compromise – “carry primes instead” was the mantra back them. So even with the lens hood I wasn’t expecting much, but was pleasantly surprised except when I really tried to get the lens to flare. Here’s the worst I could do :-

Shooting straight into the sun shows up some complex flare due to those 8 elements. 48mm f22.
And just like the 21mm f3.5, you can get a very odd circular flare. If you like the sun in the middle of the frame! f22, 28mm.

However in most normal situations it’s not really a problem :- and it will do sunstars of a sort, but it’s not a headline feature!

Slight green flare lower right, not really that noticable.

Bokeh. An f4 wide angle zoom which focusses to 65 cm is never going to be great at blurring away backgrounds. For that you’ll need a fast prime or a telephoto. The 28-48 does produce a pleasant, if modest background blur as you can see :-

48mm f4, a couple of feet away.
48mm f4 at minimum focus distance of 65cm. Not that bad really, but not a 50mm f1.2…
Close up again, 40mm ish, included because, well, I like the sign! E Archdall Ffooks has many such signs on bridges all over Dorset, a full time job it seems!

Sharpness. In the centre through the viewfinder things look pretty sharp for focussing purposes but lets have a closer look an do some pixel peeping….

All based on the following inspiring view :-

28mm f4 Centre and Edge

28mm f8

48mm f4 Centre and Edge

48mm f8 Centre and Edge

So what to make of all this? Centre performance is always good, only the extreme edges lose it a bit at f4, closing to f8 reduces the extreme corner’s softness but it’s never completely eliminated. 48mm seems sharper that 28mm (as you would expect).

In conclusion, the negatives first – vignetting and CA (correctable), some flare if you go looking for trouble, and a limited zoom range and aperture make this not quite a match for the Sony FE 24-104 f4. It would be great if it went a bit further than 48mm, but there you go.

The positives though – small, well built, sharp for most of the frame, good contrast and colours, £80 (rather than £1000 for the Sony), and it doesn’t attract attention. It sits beautifully on the A7R and is perfect for a walk around lens if you like these focal lengths.

All in all, recommended. pretty good for a 40 year old lens!

Hope you find this useful.


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