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 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 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.
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!
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.
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!