This Canon Serenar 35mm f/3.5 is in nice condition, but the aperture ring is a little stiff. Plus, I’ve already cleaned the other two so I might as well do the entire set.
I thought this one, being the smallest, would be the easiest. It wasn’t. I had a difficult time reassembling the rear section. For some reason the black painted plate was locking up the helicoid. I eventually got it and the lens works like new. The aperture is now fantastically smooth, partly because it is click-less from the factory.
(follow the images left to right, top to bottom)
The Canon Serenar 35mm f/3.5 is a tiny lens, but still full frame.
Start by removing the four screws around the M39 screw mount.
Remove the ring.
This lens has an odd double nested helicoid. One of the two sets of threads is redundant. The lens fully operates without the outer ring, you just can’t mount it on a camera.
Use a spanner tool to remove the black spanner nut. Be careful of the 65 year old paint.
With the spanner nut removed the two sections separate.
The black pin aligns with the slot on the front lens section. This picture will help in reassembly.
Notice the crimps on the aluminum. They have to be pushed out to allow the small spanner nut to unscrew.
With the crimps pushed out the spanner nut can be removed with the spanner tool.
The spanner nut is loose, but trapped.
This piece won’t slide out either.
Unscrew the knurled ring to free the previous parts. You can see where I pushed the crimped aluminum out.
Unscrew these two screws to remove the arm.
Now the spanner nut is free.
Now this part is free.
Here’s a nice layout of the parts in this section.
The stop screws in the piece don’t need to be removed. They aren’t in the way of anything.
Remove the four painted screws on the other side. Be careful once again with the 65 year old paint. They have a bit of thread locker so they don’t come out so easily. Be sure to apply great pressure on the head while turning with force. You’ll have to either hold the piece carefully or set it on something to support it because the metal ring beneath it is thin and can be bent from pushing on it too hard.
Even with the four screws removed it is difficult to slide out. Carefully pry it loose by moving a thin tool around the edge. The paint is likely to be scratched in this step.
A gap is formed after prying around the piece.
Finally it’s free. Note how the two tabs line up with the plate.
These two pieces will now unscrew.
Acetone cleans the old grease nicely.
Use a toothbrush dipped in acetone to get the grease out of the threads.
Remove the brass washer from the front lens assembly.
This screw connects to the aperture ring.
Remove the aperture pin. During reassembly be sure the head clears the surrounding parts. On this lens it was sticking out just a little too far and was sticking.
These two screws need to come out.
Looking at the front of the lens, carefully remove the plastic ring with a spanner tool. Any marks you make here will be seen forever.
The front element is removed.
Use the spanner tool to remove the next lens element.
Removing this element reveals the aperture blades. There are six small blades on this lens.
Use the spanner tool to remove the spanner nut and the aperture housing and washer come out.
There are two thin split washers sitting in a groove. Carefully find the gap in the washer and slide it out of the groove.
You can see the gap in the split washer. Slide it off.
Slide off the second washer.
Now the pieces come apart.
There’s a lot of parts for such a little lens.