Repairing Canon Serenar 85mm f2

[Roel]

I have a beautiful (and heavy) Canon Serenar 85mm f2. The aperture ring is a bit stuck and i see big flakes of stuf lying on the aperture blades. Looks like coating from the barrel.

Anybody know how to open up the lens to have a better look? Is it difficult for this model. Maybe even a link available?

Would like try the lens on my Leica Monochrome.

 

[ferider]

Just unscrew (by hand) the front part of the lens and you'll get access to the aperture.

 

[Roel]

Hi Ferider,

just tried but nothing gives any motion and i am not exactly sure which frontpart you mean. I am afraid to break something. Also should i open it clockwise or the other direction.

 

[ferider]

Grab the entire front part including aperture ring and turn counter clock wise. I only have pictures for the Nikkor 85/2, but I have cleaned the (chrome) Canon 85/2 as well, and it was similar. Here you can see how I did it for the Nikkor lens:

http://ferider.smugmug.com/Technical/Lenses/Nikkor-852-CLA

Then you can access the rear part of the lens and uncrew that to see the aperture.

Here you can see a picture of the disassembled Canon 85/1.9 (almost the same lens as yours):

http://www.rangefinderforum.com/forums/showthread.php?t=123081

Roland.

 

[Roel]

Thnx Roland,

This is very helpful! So no screws to loosen first. Only thing is that if I grab the frontpart including aperture the whole thing still doesn't move a bit. Maybe I should eat some energy bars and try again. It's so fixed i am afraid to damage the whole thing by applying even more pressure.

Will try again later.

 

[peterm1]

Are the "big flakes of stuff" black in color? If so its the black paint from the inside of the lens - applied during manufacture to reduce internal reflections. Its pretty common with some older lenses in fact and is nothing much to worry about as it is easily rectified.

 

[Roel]

Yes the big flakes are black/dark greyish and look like paint. Even seem to have some curve.

But first I have to open up the lens..

Are the "big flakes of stuff" black in color? If so its the black paint from the inside of the lens - applied during manufacture to reduce internal reflections. Its pretty common with some older lenses in fact and is nothing much to worry about as it is easily rectified.

 

[Roel]

Flakes

Flakes

Yes the big flakes are black/dark greyish and look like paint. Even seem to have some curve.

But first I have to open up the lens.

Are the "big flakes of stuff" black in color? If so its the black paint from the inside of the lens - applied during manufacture to reduce internal reflections. Its pretty common with some older lenses in fact and is nothing much to worry about as it is easily rectified.

 

[ottluuk]

Use something rubber to give you a better grip. Clean work gloves with rubberized palms, a piece cut from an old bicycle inner tube, the kind of rubber mats intended to help open jars etc. When you try this bare-handed, you can squeeze till your knuckles go white but you can't apply very much twisting force at all.

 

[View Range]

The 85mm f2.0 Serena lens head does not simply unscrew. The f1.9 does, but not the f2.0. There are three set screws on the focusing ring. Perhaps removing them would free the lens head.

 

[oltimer]

Leicabuff on EBay has one for sale now in the 1.9, and he shows it apart as Ferider explains above. It might help you understand his thoughts better in seeing this one?

 

[Roel]

I managed to unscrew the front part and get out all of the paint chips. The inside of the barrel between the apperture blades and the front lens part looked perfect. So I wonder where the paint comes from. Could it be that the paint is from the glass? The bevel of the glass is clear without paint. Does anybody know if this should be painted?

[/url]Canon Serenar 85mm f2 by RoelvanNoord, on Flickr[/IMG]

 

[hanskerensky]

I have seen several other lenses were indeed this part was painted black. No doubt to lessen internal reflections.

 

[Roel]

Thanks Hans,

Is it possible to paint it yourself or is this the time to bring it for cla to an expert.

I have seen several other lenses were indeed this part was painted black. No doubt to lessen internal reflections.