Soligor 28mm f2.8 - Canon FL to Nikon F Conversion Guide

[Scheimpflug]

Hello everyone. This is my first post here - I'm hoping to both share a bit of information and get a few questions answered.

I recently acquired a small pile of old lenses, one of which was this Soligor 28mm f2.8. It had a Canon FL mount, which I couldn't use, so with the help (parts) of a reject Nikon 35-135 zoom, I was able to complete the conversion to a Nikon F mount. Below are the steps.




First up was the removal of the bayonet ring. One screw (the silver one) was removed, and the ring simply unscrewed off of the end.


I then had to remove the thick base of the Canon FL mount, which was accomplished by removing five long black screws around the perimeter. The aperture stop-down pin & linkage came off with the mount, and the auto/manual slider from the side of the mount also came free.


With the auto/manual slide switch removed, the lens was spring loaded to switch into the manual mode, with the aperture always reflecting the setting on the aperture ring. I've never seen a lens with this star-shaped aperture before, but from what I gather it is normal for this particular lens? It is round when wide open, and also when stopped down to f16.


Next, I switched to the donor lens for the Nikon F mount - a 35-135 with a gummed up zoom.



Removal of the four silver philips screws loosened the mount assembly, but did not let it come off due to the electrical connections. The black plastic light baffle had to come out first, which was accomplished by removing the small screws around its perimeter and pulling it straight out. The electrical contacts could then be pushed out of the way (inward), freeing the aluminum mount.





Now it was time to put the pieces back together. The two lens mounts had different hole patterns, used different size screws, and were arranged at a different radius... but to my surprise, they were actually close enough that I could attach the mount with two screws on opposite sides! The original Soligor screws were much too long for the thin Nikon mount, but two screws from the now unused stop-down mechanism happened to be the right threads. In the first two pictures here, I have already removed one of the two screws and installed it into the lens mount.




This looked great, but it turns out that the screw heads were slightly too thick, and protruded enough above the recesses in the Nikon mount plate to prevent the lens from latching to the camera. The search was on for alternate screws, and once again the Nikon 35-135 provided the parts. The small black screws holding the aperture ring to the lens body had the same threads, in the correct length, and with short screw heads! What a coincidence! Here is the Nikon lens with one of the screws already removed.


And that was it! With those two screws installed, the lens now mounts perfectly to the Nikon D40.





Additional Comments:

* The mount can be rotate to several positions and still pick up two screws. I placed it in the orientation which put the aperture settings visible from the top. It is rotated slightly to one side, but is still perfectly usable. (Note that it is at the wrong orientation in the photo above, as the aperture settings are on the side.)

* I did not reinstall the A/M slider, as the mechanism behind it is gone. This left a small slot in the side of the lens which was open to the inside. To avoid light leaks, I wrapped a slim piece of electrical tape around the joint between the lens body and the mount. (I'll try to get a picture, it is hardly noticeable.) I would like to install the plastic baffle from the Nikon, but it will need some trimming to fit.

* The lens can't focus to infinity - it stops somewhere around 20 feet. However, at f16 the depth of field is great enough that it seems to be usable for landscapes if there is enough light. I don't have the tools to machine the lens barrel down, so I'm not quite sure how to resolve this? Does anyone know if the hard stop at infinity focus can be adjusted on the Soligor lenses?


I'll try to post some samples once I have had more time with this lens.

[poilu]

[djmike]

Scheimpflug, thanks for sharing~ Mike

[supahmario]

hey scheimpflug, welcome to the forum.

[indianadinos]

Hi, welcome to the forum and thanks for sharing your hints ...

Cheers

[Scheimpflug]

Thanks everyone.

I didn't catch it when I posted, but does anyone have any ideas why the images didn't work in my first post? They appeared fine when I previewed the post, and show up just fine if I edit the post and preview it again from there. They also show up in poilu's quote of my post, although I can't see anything different in the code...

I have the pictures hosted on Photobucket, and inserted into the post using the standard "img" tags...

Are new users restricted from placing images in their posts?

[Attila]

Welcome! Thank you for this nice entry! Yes, new users can't publish links, images this is a spam prevention.

[Scheimpflug]

As promised, here are a few quick samples with this lens on a Nikon D40.

Roses at f2.8:



A cathedral tower at f16 - bonus points to whoever can name it.
Essentially, this was the test of the practicality of making up for the "not quite infinity" focus using depth of field. For what it is worth, the camera would not give a focus confirmation for this shot, while it did for the previous shots. The second photo is a 100% crop from the center of the first.



These aren't very artistic, just some quick examples to show that the lens actually works. I didn't do any post-processing other than the resizing and that one crop.

[greg]

Welcome to the group and thank you for your well documented work.

[mo]

Christchurch or Dunedin for the cathedral? Nice job on the lens.

[Scheimpflug]

[mo]

When the rugby is played there they nearly always include a shot of this landmark