Jupiter 11 4/135 modified to fit Alphax shutter for 6x9

iangreenhalgh1 · Expire: 2014-01-07

I happened to have a spare J11 I didn't need (I have them in M39, M42 and Contax/Kiev) and a spare Alphax #2 shutter so I decided to get out my trusty hacksaw and mate the two together so I would have a Sonnar to use on my Century Graphic to shoot 6x9.

Took about 2 hours, tools used were a hacksaw, a small flat head jeweller's screwdriver and a sheet of emery paper. A little bit of epoxy putty et voila - a J11 in shutter.

Alphax #2 shutter, I bought it dirt cheap because the slow speeds didn't work. Quick squirt of lighter fluid followed by a drop or two of 3in1 oil and it runs like new.

This is the optical block of the J11, it just unscrews from the helicoid. I made sure to measure the length before I started cutting it up so I could ensure it ended up the same length again after mounting in the shutter and correct element spacing was maintained.

This is the optical layout of the J11, note the large gap between third and fourth elements, meaning there is a nice big area where I can hacksaw through without fear of hitting any of the glass.

The J11 has 12 blades making for a nice round aperture. The Alphax only has 10, but still enough to give a pretty round shape.

I cut the optical block in half where the thin black tube joined the larger front part, tthe aperture mechanism was inside this black tube, I removed the two rings that formed it, no blades in the picture becuase they flew out onto the floor.

Next step was to remove the outer aluminium barrel that has the aperture ring, not needed anymore as there is no aperture left.

The photos to illustrate the next step are missing, but what I did was cut away the metal surrounding the rear of the front part of the block, which is the gray coloured portion. This exposed the conical back of the third element, a little careful work with the emery paper and this front part now sits perfectly in the front of the shutter.

This shows how the back of the front part sits inside the shutter, no more than 1mm clearance between the shutter blades and the glass.

I used a bit of epoxy putty to secure the front half to the shutter. All that was left now was to mount the back part to the back of the shutter.

I had to maintain the same overall length of the optical block to ensure proper spacing of the elements. I would modify this length by shortening the tube of the back part. Measuring carefully, I worked out that I needed to shorten the tube by 2.5mm, which I did by rubbing it on a sheet of emery paper.

A little more epoxy to secure the rear part, et voila, J11 a la shutter...

Lloydy · Expire: 2022-01-01

Great work Ian, I guess we'll have to wait and see the results?

iangreenhalgh1 · Expire: 2014-01-07

Cheers Dave, here it is fitted to the camera:

I made a quick test shot, wide open, and dammit, it doesn't come close to covering 6x9.

I hope coverage will increase on stopping down. I'll mostly be using this lens for close work anyways, so fingers crossed it will cover okay at 1-3m which is where I will be using it.

iangreenhalgh1 · Expire: 2014-01-07

I tried it for a close-up and it works fine, no vignette and that lovely smooth Sonnar bokeh. Ilford FP4 in stock Kodak DK50. 1/5 sec at f4:

iangreenhalgh1 · Expire: 2014-01-07

It rained all day today but in one of the short breaks in the rain I managed a test shot at infinity but with the lens stopped down to f22. It still doesn't quite cover the full 6x9 frame but the image circle is a lot bigger. IQ is nice too. This was with Agfa Litex double-sided graphics arts film which is not quite as sharp as a single-sided film and is only sensitive to blue light, but you can tell the performance is more than adequate. 4 seconds at f22:

philslizzy · Joined: 07 Aug 2012 Posts: 4748 Location: Cheshire, England

Excellent work Ian. This lens is designed for 35mm correct?. It has a helluva image circle to almost fill 6x9.

well done

iangreenhalgh1 · Expire: 2014-01-07

Cheers Phil. Yup, it's for 35mm. Quite a few 135mm lenses have large image circles. the Meyer Primotar 4/135 has a removable head and will cover 6x6, not sure if it will cover 6x9. The Leitz Hektor 4/135 will just about cover 4x5".