The last post was a quick review of the Zuiko 18mm f3.5 on a Sony A7R. The only nagging problem was how to attach filters given that the front of the lens bulges about 3mm out from the lens housing. Olympus made a filter step up ring for this purpose, but as it’s now very difficult to find it’s expensive – £100 or more. As long exposures or video shooting require neutral density filters this needed to be fixed.
The 18mm doing what it does best…
The two problems are that the step up ring(s) needs to be deep enough so that the filter doesn’t foul the front lens element, but the deeper the step up ring the greater the chance of vignetting (this lens has an angle of view of 100 degrees or so). A simple 49-77mm step up wasn’t going to work.
The front lens element bulging out from the lens – it looks vulnerable and prevents flat 49mm filters being used.
The solution was to use not one step up ring but two. The first, a 49mm to 58 mm provides a thread 2mm further away from the lens, then a 58mm to 77mm adds a further 2mm. The 77mm filters are wide enough they don’t darken the edges of the shots (vignetting). I’d like to say I did some careful calculations to work all this out but I can’t – I ordered a cheap 58-77mm step up and it just worked so sheer luck really. 77mm was chosen as the filter size because I have several pricey neutral density filters in this size.
From the top – a UV filter, the 58-77mm step up and below that the 49-58mm step up.
One unexpected benefit is that the step up rings will stop my the tip of my left index finger wandering into the bottom left hand corner of the frame – this happens a lot due to the wide angle of view!
Not the slickest appearance – but the ‘proper’ Oly solution looks about the same and costs a lot more. It does look impressive from the front though.
Problem solved for around £2 (I already had the 49mm to 58mm ring) so a definite result. It’s an ‘assemble on site’ solution as it’s not that strong and would probably get damaged in a camera bag.
Not a long exposure requiring a filter – just a nice shot from yesterday using the 18mm, included purely because I like it!
The audience for this incredibly niche post is tiny – but if you’ve got this lens (or are thinking of buying it) hopefully you’ll find it useful!
28mmf2 
You lucky so and so! I tried a variety of those step-up rings and all gave me vignetting 😦
Sheer luck Doug!
You’re right. It’s is very niche but also very helpful to me. great stuff
That’s good Tom – glad it was useful. It would be worthwhile using some better made step up rings as the ones I used were pretty cheap and nasty.
I’ve swapped the 18mm for a 21mm f3.5 Zuiko which is a bit less wideangle but more practical – I was always very worried about that bulging front element. It vignettes less too.