Rangefinder with glasses? A mod made from necessity

Anyone who is a glasses wearer and rangefinder enthusiast then this issue will be familiar with you. A quick google search for ‘rangefinder camera with glasses’ will expose you to a ream of forum posts and question sites of photographers all experiencing the same thing. They can’t see the frame lines in their viewfinder, due to us spectacle wearers not being able to get our eye close enough to the viewfinder to make full use of it.

Unfortunately, I found this out the hard way. I’ve owned a fixed lens rangefinder in the past and although I had to press my glasses tight up against the viewfinder, I was indeed able to see the frame lines. Fast forward and after using a Pentax SLR for a year, I decided I preferred the shooting style of a rangefinder and wanted something a bit ‘nice’ that I could treat as my main shooter.

While on honeymoon in Japan I was hunting for a Canonet for my wife I managed to fall in love with the thread mount Canon rangefinders. The camera in particular being the Canon VI-L with the rotating viewfinder system. After a few weeks scouring the internet I’d ordered one up with their famous 50mm F1.7 from eBay.

When this arrived you can imagine the excitement to get out and start shooting… however… moments after unboxing my issue was apparent, I couldn’t see the frame lines with my glasses on.

Initially disappointed, I turned to the internet and that’s when I discovered that indeed rangefinders and glasses mostly do not mix. While lurking forums, people talk of getting Leica viewfinders converted to 0.58x and of a Japanese company in the 2000’s making a 0.85x screw mount magnifier to minimise the viewfinder image.

Outside of this no one seemed to have a solution apart from ‘maybe try another camera?’

I decided to put the negativity behind me and took this camera on its maiden trip to the Lake District. After taping around the eyepiece to protect my glasses from being scratched when pressing up against the eyepiece I really enjoyed shooting the camera. However, I found having to manoeuvre the camera around my eye to get an idea of framing grew tiresome quickly, and nothing fast action was going to get shot with this setup.

As mentioned, I had come across a screw in 0.85x magnifier that would likely do the job if I could get it fit on the camera, the problem being this is extremely rare and wasn’t able to come across one for sale.

So there was only one option, make one.

The Build

After some research and relearning my school physics class on optics, I decided to give it a go.

First was working out the lenses I needed. After some crude calculations I had devised a system made up from two lenses, a plano concave and a plano convex. The key here was to ensure that this arrangement was small enough to fit into an eyepiece to sit behind the viewfinder and give the desired ‘de-magnification’ I required. The goal here was to create an overall length of around 2cm and achieve a magnification factor of 0.60x. Going off the Leica forums around this issue it seems the 0.58x offered by Leica was the go to for any glasses wearers, so this should get me close enough.

The Canon VI-L much like other cameras from the time has a screw in rear element. This was able to be screwed off and replaced with various diopter adjustments which were sold separately, and extremely rare. With this rear piece removed this gives the perfect threaded space to mount the new modded eyepiece to. I will add that I did consider tracking down a diopter adjustment lens for my eye sight, however, this would have only resulted in taking off my glasses every time I wanted to shoot.

Next was to design and manufacture the housing. I had been passed down my grandfathers hobby lathe from the 1950’s and with a few ‘successful’ projects in the past it was time for it to perform again. I used a polymer called Delrin due to its ease of machining and to my surprise I was able to come up with a working housing after only a couple of attempts.

The design comprises of two pieces which contain a lens each (plano concave at the camera side and the plano convex at the eye side). This allowed for me to very carefully dial in the focal length between the two to achieve a sharp focus.

Once complete I used an epoxy to sandwich it all together. This epoxy is designed for golf clubs as it allows for some flex and hopefully this will save it in the future from an accidental drop. I wrapped this in electrical tape just to ensure that if it did decide to come apart hopefully it would stay together long enough for me to notice and save my precious creation.

Next I fit this assembly into the camera. Due to the softness of delrin I was able to make the inserted end ever so slightly larger than the threads of the camera eyepiece. By turning the assembly into the camera this essentially ‘cut’ the threads and to my amazement fit nice and tightly.

The Result

You’ll see from the photo this worked really well and my calculation of a 0.60x magnification factor seems correct.

A few things to note:

By minimising the viewfinder image comes a smaller focusing patch. The one on the canon is relatively large and doesn’t pose much of a disadvantage over the original, however, on other cameras making this smaller may become an issue.

Due to the wide angle nature of this mod the edges of the viewfinder are slightly fuzzy however for framing purposes are more than satisfactory. The centre is pin sharp which is just as easy to focus as before.

Overall I’m very pleased with how this project turned out and hopefully this has sparked some hope with anyone who has the same issue with their own rangefinder, glasses or not.
If you have any questions regarding and want a bit more detail please get in touch, my Instagram is @postnostills https://www.instagram.com/postnostills/, I’d be glad to give you some advice.

Thanks for reading,

Christie

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