How To Fix a Lens!

This could be really boring.  So if you get tired of hearing about how I fixed this lens, you have permission to leave the class!  This one of the two parts I got when my friend gave the lens to me to try and fix.  It is the bayonet mount that attaches to the rest of the lens, and the side facing down attaches to the camera, and this was broken off when the lens and camera crashed to the pavement.  Notice the four black pieces sticking up from the silver circle?  Those are the plastic posts that are supposed to connect this bayonet ring to the body of the lens.  They fractured off when the lens crashed.  And notice the orange ribbon cable sticking up - that was ripped out of its connector when the lens was broken in two pieces.

This is the rest of the lens body, with a circular circuit board attached by the two orange ribbon cables, and a third ribbon cable that sticking up.  Eventually that will have to be attached to the circular circuit board.  The red lines each point to a ragged spot on the lens body where the plastic posts were before they fractured off in the impact. This lens is a completely different animal from the old camera lenses that were all completely mechanical.  This lens is completely electronic.  There are no gears for focusing, or for moving the diaphragm which changes the opening through the lens. Everything is done with little stepper motors that are connected with these ribbon cables.  The focusing is done electronically with little stepper motors as is the setting of the lens aperture as well. It is a whole new world out there with these modern cameras and lenses.

This is a close up of the back of the bayonet ring.  Notice the nice clean hole in it, it is where the screws go through to fasten this ring to the black plastic posts.  You can see how complex the ribbon cable is as well with each orange strip acting like a separate wire.

The force of the crash was so strong, that the screw that went through this hole, tried to pull through the bayonet ring and deformed it before the black post broke off.  I had to grind these rings down flat as part of the repair.

Here are the two parts of the broken lens, while I was getting ready to glue the bayonet ring with the little black posts still fastened to it, back on to the lens body.  The lead weight weighs about 10 pounds and will be used to hold the two pieces together after I put drops of glue on the little posts and then position the ring and the posts over the body of the lens.  The square of blue masking tape is protecting the rear element of the lens from any damage while I am working on the lens.

Here the lens is, where it sits for 14 hours while the industrial epoxy cures.  When I was sure that everything was glued properly, I removed the screws from the bayonet and removed it.  Then I could fold in the circular circuit board to where it belongs inside the lens.  You can see the tips of that board above the weight.  Then I had to delicately re-attach the three ribbon cables you saw sticking up in the air in the first two photographs.  My fingers are large and working in a small space with such delicate and small pieces was not easy!  

And here is the repaired lens.  I was actually stunned when I put the lens on the camera, turned the camera on, and pushed the shutter release on the camera.  There was a little whir from the stepper motor and I the lens focused!  I was astounded!  I could not believe that I had actually managed to get the lens working.  It is not perfect - the lens can not be focused manually, and the little digital readout in a window on the lens doesn't light up.  BUT...  I can take photographs with this!  The photographs are not perfectly sharp when I use the lens at f/2.8, it's maximum aperture but stopped down to f/5.6 or f/8 the images look perfectly sharp.  Wow!  I can't believe I managed to do this!  The cost of this lens when new was $1,400 so it is amazing that it will work again after the damage, even if it is not perfect.