The Halina in the previous post is the second in my collection and the body lacked the lock screw so it falls open easily. My intention is to revamp the camera into a pinhole camera. As such it will be even smaller than with its lens on, a really tiny camera and visually I do not care if I have to use sellotape to keep it together in that case.
That leaves me with the two element lens for “alternate use”. I decided to try it to a EOS bayonet for use on my 5D2. This is what I did:
I had a Konica->EOS-adapter around and used that as the bayonet. The first step was to find a suitable part of the lens for fitting the konica threads. As it turned out the dimensions were almost correct and only a small amount of grinding was necessary. When the outer diameter was almost the same as the adapters inner threads I simply made a press fit (with some blows from a hammer…). I took some photos of the result but as the actual machining was a dirty business I had no camera around for documenting it. Anyway I ended up with this:
The distance between the lens and the EOS film plane (the register distance) is much smaller than for the original Halina. In the above picture one can see a first step in decreasing that distance. In the end I had to grind away about half the size of the numbers too.
Quite a lot of trial and error had to be performed until the entire unit could focus at infinity. Several hours of repeated cleaning, assembly, focus testing, disassembly, further grinding, cleaning etc. Each step was tested on the 5D2.
To be able to set the infinity distance the distance ring had to be much lower, or it would jam when getting close to infinity (screwed in). Unfortunately that meant the actual distance numbers had to go. This is taken at the beginning of this grinding phase:
Here the lens is in one of the final assemblies before testing again. In this state infinity was not yet reached (!). So it had to be taken apart a couple of times more. This constant testing made me confident it was possible to grind off more metal and still have some threads left for focusing. In each step about 0.5 mm was grinder off, then testing again!
The final lens had only about 1/3rd of the threads for the focusing ring compared to the original. Now I miss being so diligent in removing all that dried grease, it would have come in handy here. It moves very easily now.
Finally the working lens fitted onto the DSLR. The lens was small to start with and is now considerably smaller. Adjusting aperture and distance is a fiddly business and not really practical, but can be done.
Now is this lens useful? Sample photos are in a later post.