A BIG heads up on cleaning a Fujinon EX enlarging lens

[Arvee]

I used a flashlight to inspect the internals on my 50mm f/2.8 Fujinon EX lens and saw a bit of haze that needed attention. Being handy with a screwdriver, I thought "Piece of cake!"

BIG surprise! When you unscrew the front cell, the entire set of (8) aperture blades and retaining ring came out in a nice little jumbled pile. The front cell is the piece that holds the blades and retaining ring in place.

And, let me tell you, it is no easy task resetting those blades and placing the retaining ring!

Just a heads up in case you're thinking about doing a CLA on a Fujinon EX 50mm f/2.8 so you don't fall into the same situation I was in! I did, however, after several hours of trying different approaches, successfully reassemble the lens and put it back into rotation.

 

[jjphoto]

Thanks. That's good to know. Did you happen to take any pictures of the debacle? Any tips on putting it back together or a better approach to clean the elements?

 

[Old-N-Feeble]

I'm sorry that happened to you. Do you think it's easier to remove the rear cell instead?

 

[Arvee]

Sorry, I should have provided the proper way to go about the cleaning procedure. You can easily remove the rear cell without risk. Simply unscrew, clean and replace; don't lose the brass washer/ring. Then, sit the lens on the rear cell and unscrew/remove the front cell, slowly and gently, without disturbing the body/rear cell. Lift out, clean and replace the front cell; again, do it slowly without tipping the lens body away from the vertical axis. The pivots on the blades are very shallow and only held there by a thin plastic retaining ring that doesn't weigh very much and, if it lifts more than 0.010-0.020", the blade pivots will come out of their sockets.

The problem occurs if you pick up the body/rear cell and jar, tip or invert it. You shouldn't have a problem unless you (as in my case, foolishly) pick up the body and tip it.

BTW, this is the first of many enlarging lenses that I have cleaned that the aperture mechanism wasn't riveted/secured in the body.

PS. If I were to do it again, I would find a way to make sure I didn't accidentally bump the lens body while cleaning the front cell. Perhaps a wooden vise or, at least, wrap in a heavy towel to prevent tipping. Just finished a print with it; good as when it was new!

Hope this helps,

 

[jjphoto]

Thank you!

 

[paul ron]

hahahahaha how many of us have been surprised by a jack in the box with ball bearings n springs flying off into a black hole never to be found again.

glad you got humpty back together again.

 

[Arvee]

I was recently repairing a Canon Ftbn and was in the process of installing the detent ball bearing in the rewind shaft/collar and I deposited the ball (0.020" dia.) into the collar and...presto...it disappeared. Figuring it bounced onto the work surface I began the search...no luck...searched the floor, got out the magnet and combed the area to no avail. Three days later after multiple search expeditions, i gave it up. Four days after that I had a thought and pulled the rewind shaft. Sure enough, there was another tiny opening into the top of the camera. Removed the top cover and inverted the camera and out popped the tiny ball bearing. Tacked on a dab of vaseline and reinstalled. Like new!

 

[David Lyga]

Yes, I had this same problem with a German enlarging lens (cannot remember which it was). There are all sorts of deviousness out there in the repair world. Expert repairmen are worth their weight in gold.

And, yes, Fred, that rewind crank in the Canon mechanical body has that ball bearing to provide a rather (unnecessarily sophisticated) stop gap when pulling out that crank. - David Lyga