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Lens and Optics
Jupiter-11 Lens Dismantle and Relube


I am always amazed by the generosity of complete strangers. A certain Carlo Nicolucci of Italy answered the call of the Kiev Survival Site that we had no Jupiter-11 to dissect for your pleasure. As indicated in this email, "Your site is very useful for me and I want to thank you for this. Can I give you a Jupiter 11?"

So now, brought to you by Carlo Nicolucci, dig out your crummy old Jupiter-11, 'cuz it is time to have some fun!


Witness one well used dirty old lens. Note the corrosion on the nose barrel.


Get one of these handy rubber mats that are intended for use in the kitchen for aiding in twisting off stubborn jam jar lids. This makes the initial start to undoing the threaded lens block just so much easier. Grab a hold of the nose of the lens and unthread the inner lens block assembly.


Unthread the assembly all the way and remove as a unit. Make note of the spacer shims used to set the proper lens offset. When it is time to play around with setting the working distance of the lens these shims will be increased or decreased as needed.


So, with the lens into two separate units, you may choose to work on either. I flipped a coin and came up with the focus helical base first.


Undo the 3 set screws around the focus ring collar.


Slide the focus ring collar off. You will observe the exposed focus helical if you have the lens set to minimum focus distance.


Loosen the 3 set screws around the collar of the lens bayonet base assembly. Note, I have set the lens to infinity for a reference position.


Since most of you may not have a spanner I will show you how to perform the next step without the need for one. Unthread the lens helical assembly from the lens bayonet base.


Remove the one set screw holding the threaded ring in place.


Remove the threaded ring.


Slide the focus coupling off.


Loosen the 6 set screws around the focus scale cylinder.


Slide the focus scale cylinder down to remove.


Pull the coil spring off.


With the lens set at minimum focus you will see an access hole along the helix groove. This hole will provide access to the backside threaded insert of the helix slider. The screw for the helix slider is highlighted by Yellow Arrow. Remove the stop screw as indicated by Blue Arrow.


To remove the two screws that are part of the helix sliders, set the lens to infinity. You will see the helix slider from the inside align with the access hole. Most have a slot so that you can place a screwdriver on the backside threaded insert. This one did not but I braced a screwdriver against it anyway.


Viewed from the outside, remove the two screws while holding a screwdriver against the threaded insert on the helix slider on the inside. You may need to grow a third hand to do this.


Slide off the outer helical collar revealing the helix sliders as shown.


Clean all the dry gummed up grease on all parts of the focus helical. I use Lacquer Thinner as my solvent of choice to cut through the old dry grease.


Re-grease the helical assembly. I think I went a bit overboard with the application of grease. Insert the helix sliders into place situated over the access holes. Note how the slotted face of the threaded portion of the slider is facing inward such that you may insert a screwdriver from the inside through the hole to secure it.


I find this grease to be good for such uses. It will not creep or flow. I did this test over a year ago where I placed a dollop of grease on a sheet of glass and left it. Here are the results. No slumping or running of the grease. There are several special dampened helical greases available if that is to your preference.


Here is a close-up of the helix sliders to understand just how they go together.


Slide on the outer helical collar so that the screw holes line up with the pre-positioned helical sliders. Insert the two screws to fasten the helix sliders.


Remember to install the stop screw.


To re-assemble threaded ring, make note of indented hole where the set screw seats into as shown by Yellow Arrow. When you re-assemble align this indent with the set screw hole shown by Blue Arrow.


Insert the focus coupling into the bayonet base.


Thread the focus scale cylinder onto the threaded ring until the three indents align with the set screw holes.


You will probably notice the focus coupling can rotate freely. So, in what position is it supposed to be in?

One way to pre-align the position of the focus coupling is to mount it to something or some camera.


Stick your finger down there and rotate the focus coupling until it engages the slotted receptacle of the camera focus drive. Now set the focus to infinity.


Insert the helical unit such that the slot will engage the spline on the focus coupling.


Slide the helical unit completely into place and insert the six set screws around the focus scale cylinder to fasten.


Apply the focus ring collar and  tighten the set screws. The set screws should align with the detents from their previous locations on the helical unit.


OK you are now done this part, give it a test. How smooth is that? Your Jupiter-11 should now rotate silky smooth.

Lens Element Block

First thing you go to do is get this vulnerable lens element out of the way of harm. Remove this and put in a safe place.


Remove the three set screws around the aperture selector ring.


Remove this screw that engages the aperture selector ring with the aperture mechanism itself.


Unscrew the aperture selector from the lens block unit.


Undo this set screw. Now in theory you can unscrew the front lens elements from the body but this guy was not going to come loose no mater what I did. My hope was that I would reduce the lens body down to the bare bones and put it into my ultrasonic cleaner to loosen it up. Read on you'll see what happens...


Using your spanner, remove the front lens ring.


Carefully lift out front lens and place on a safe, soft location.


Get in there with your spanner to remove this lens ring.


Lift out the next lens element. Now, make sure you have a good hold as this sucker is one serious hunk of glass.


See what I mean? One large cemented lens block.


With all the glass out of the way you can turn your attention to cleaning. I had some corrosion to clean up first. A wire wheel in a motor tool and some buffing did wonders.


After soaking in an ultrasonic cleaner I decided to give unscrewing the front lens block another try. I got lucky!


Here's the front lens unit removed. If the threads had not proved to be such a problem one could merely remove this as a unit with glass lenses in place to be disassembled as a separate unit.

Clean all the dry gummed up grease. I use Lacquer Thinner as my solvent of choice to cut through the old dry grease.


If you are brave we can go in deeper to get at the aperture unit itself.


Remove the snap ring and carefully, and I mean CAREFULLY, lift out the aperture rotator without disturbing any of the individual aperture leaves. Well, I suppose you could mess with the aperture leaves but take my word for it, it is best to leave these alone if you can.


Use a well dampened non-creeping grease to make the aperture turns nice and smooth but with a little resistance. Nothing worse than an aperture ring that turns too freely. Again, very carefully lower this aperture rotator back down onto the pins of the aperture leaves. If all goes well fasten down the snap ring.


Turning our attention to the glass I noticed that the interface between two cemented elements significantly has the absence of any paint to reduce internal reflections.


Notice the reflective surface at the interface of the cemented lens elements where there is no paint.


A little flat black acrylic paint fixes this situation up.


Blow off any dust with a can of compressed air and clean the optics with a good approved cleaning system prior to re-assembly of the lens block unit.


There, how nice is that? Screw this front lens unit back into the lens block and replace the shims, screw this whole thing back into the focus helical base. You are done!

Now that you have this done you may proceed to: Checking Lens Working Distance to finish off.

June 05, 2006