Canon TS-E 4/17mm L - cleaning of shift mechanism

[stevemark]

These days, the Canon TS-E 4/17mm L may be the most widely used shift lens. When it was released it was probably the widest rectilinear lens. Not only has it a shift mechanism (12mm in all directions), but it also can be tilted (+/- 6.5°). In addition, there are two (!) rotating mechanisms, one for the shifting part (180°) and another one for the tilting part (90°). As you can imagine, the entire mechanism (including the transmission of the electronic signals to the aperture) is pretty complicated. It is not protected against dust and dirt.

I have been using my Canon TS-E 4/17mm L extensively, and a few days ago the shifting mechanism quite suddenly became not only very stiff, but it felt somehow gritty / sandy and made some strange noises. Using the dedicated shifting wheel was impossible (blocked).

Today I decided to have a look at the lens.

The lens consists of two main blocks which can easily be separated by unscrewing four screws and disconnecting the electrical tracks:

1) Bayonet & shifting mechanism
2) Lens itself & tilting mechanism

Here are the screws:


These are printed circuit connectors to be disconnected:


EDIT: The yellow circle in the image above shows the small spring pushing against an even smaller ball (about 1 mm). Be aware and keep that minuscule ball in a safe place (ball was removed before taking the image above).

Another view of the same connections:

[Doc Sharptail]

Cat/dog/pet hair

Good luck with it!

-D.S.

[stevemark]

Now we have the shift mechanism separated from the rest of the lens. Removing the bayonet is next. You need to unscew just the three red screws. The yellow on can remain.




Once the bayonet is removed, we can unscrew the large black baffle in the center:




As soon as it is unscrewed, the turning part of the shifting mechanism becomes loose:



Another view of bayonet (left, below), turning mechanism (left, above) and shifting mechanism (right):




Be aware that there's a pin which can be lost (it is not attached to the rest of the shifting mechanism). It's best to take it out and put it in safe place:

[RokkorDoctor]

Does that yellow circle in the second image in this thread indicate one of those pesky spring-loaded click-stop balls that go fly across the room never to be found again?

Good luck with the cleaning; sounds like maybe some hard grit got caught in the shifting dovetail.

EDIT: something funny going on; I tried to delete this post to keep Stephan's posts flowing uninterrupted, but the delete option from the Edit/Delete has disappeared...?

[stevemark]

Now we finally can dismantle the shift mechanism itself. First we can remove the three rather large screws above the turning knob of the shift mechanism:



The shift mechanism remains unaccessible. I am looking for further screws to open the top of the remaining body. Since I can't find other screws, I try those - but they just fix the printed circuits. NO NEED TO REMOVE THEM!!




Looking carefully at the mechanism, I can't find the solution. Maybe those scews close to the knob? NO! Again: DON'T REMOVE THEM!




Finally I start removing the printed circuit board, and here we have the solution! Just remove that strangely slotted screw (I have no idea why it doesn't have a "normal" screw):




Removing the cover gives us access to the actual shifting mechanism:




Before dismantling it we should disconnect these connectors:




Now "everything" falls apart! Be aware of yet another spring / ball !!




There's also a small bolt (about 1 cm long) falling out - more on that one later:

[stevemark]

Now it's pretty easy to clean the entire shifting mechanism. I suspect a simple, small grain of sand (or something similar) to have cause the blockage. There are signs of such a problem on one of the guide rails (red circle; the yellow circle shows again the third spring / ball one should be aware of):



In addition to cleaning I have been grinding/polishing the slightly damaged area above, using a very fine abrasive paper (grain size about 10 micrometer).


Here are some more details of the shifting mechanism:




Now we ca re-assemble the entire mechanism. It's pretty straight-forward - with one exception: Remember that 1 cm bolt? It's used to block the shifting mechanism if necessary, using one of the turning knobs on the TS-E 4/17mm L. It has to in the right position before re-assembling the shifting mechanism. The first shiws the correct orientation of the bolt:




The second image shows the correct position (ready to mount the shifting mechanism):



Everything else should be pretty easy - just going backwards

I have used a little bit of grease on the shifting rails; now shifting feels super smooth again, and I hope I can use the lens for another ten or fifteen years

S

[stevemark]

Finally an image of the lens block (center), the shifting mechanism (left) and the tilting mechanism (right). Very clean modular construction indeed.




S

[RokkorDoctor]

Another lens saved!

This is why it is always a good idea to reset the shift & tilt back to zero when storing such lenses; it prevents dust & grit from settling on the exposed greased dovetail slide surfaces during storage.

Interesting to see that the tilt, shift & rotation movements all seem to have digital (and/or analogue) encoders. Are the T/S movements of this lens communicated to the camera?

[stevemark]

[Himself]

It looks to have a lot of dust especially on the rear element.
Where/how do yo keep it? No rear cap - bottom up all the time?
None of my lenses have that amount of dust on rear element. They are pristine.
And what you have there it's a very expensive lens.

[stevemark]