Tokina RMC 35-105/3.5~4.3 (FD): Service

It has to end at some point, says my friend, the Photo Bear.

And so we would like to use this well-used Tokina to show you what we have learned in the last few months when it comes to lens repair and service.

Then we want to take care of new photo equipment projects, which again involve doing things ourselves if problems arise




The zoom, like others before it, cost a whole EUR 10 (~ USD 11).

Its condition promises some work:

• The lenses are very dusty.
• The aperture is tired, oil shines on the aperture blades, the aperture ring just feels dull when turned.
• There is some play in the focus and zoom rings.
• New fat on the helicoids would certainly be a good thing.
• And an exterior cleaning is due.

We hope that we will succeed in this project!

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We start early in the morning






The engraving ring and rubber coating on the focus ring are off.




The focus ring is coupled to the front helicoid for focusing via two plain bearings and three screws.




Filter ring off






Marking the infinity position.




The lower part of the focus ring is pushed back to reveal the zoom mechanism with the plain bearings.








Plenty of old grease, which can also be found as oil in the tube.

One of the two screws in the straight guide is broken and the screw head has become independent.

I can't fix that, but the zoom function is still there.










Dismantling the optics ...




... and cleaning with isopropyl alcohol on a microfiber cloth.

Rework with somewhat Aqua Purificata, also on a microfiber cloth, to remove any remaining streaks.

The water is only used for moistening so that the cloth does not go dry over the lens and evaporates without leaving any residue.






To remove the bayonet with aperture ring, the blocking of the locking ring must be removed.

Press the silver button and turn the ring counterclockwise.

Now the three bayonet screws can be loosened.








Look into the tube




Spring in the aperture mechanism.






Overview

Clean with Zippo lighter fluid.






I flush the zoom mechanism and the aperture with lighter fluid in several passes.

Absorbing grease and oil with Kimwipes and cleaning sticks.

Dirty job




The two cleaned helicoids.

I don't dismantle the helicoids for the macro function at the rear end of the zoom and I also flush them with Zippo.

This time it is greased with DeoxIT L260 grease: all helicoids and along the plain bearings in the zoom mechanism.










Cleaning and assembly of aperture ring and bayonet.

The aperture ball and its catch are greased too.








Assemble the optics.

Assembling the focus system and adjusting it again. To do this, I focus through the window on the boom of a distant construction crane.

With the lens sucker attached to the front lens, I turn it to infinity and fix this position with the adjusting screws on the focus ring.

Since the upper helicoid sits too high due to screwing errors, I can only move the screws with my smallest slotted screwdriver.






External cleaning with Sonax Cleaner Foam.






All parts cleaned and reunited.


When dismantling I bent a lever of the aperture mechanism.

As a consequence, the aperture row shifts, the aperture closes slightly at the largest opening, apertures 16 and 22 have the same opening.

I can correct this by bending the lever back.

Faux pas when connecting the helicoids:

I had overlooked the entry point, now the distance scale is no longer correct for all zoom positions.

But that doesn't matter because the focusing works for all focal lengths.

I won't correct this anymore because it's too much effort.

It's enough for me to know how the error came about




The Photo Bear is also happy

Here are some tips regarding focus adjustment:

• Screw in the first (front) helicoid and bring it to the stop.
• Insert the front ring with the grub screws screwed in 2/3 of the way.
• Mount the straight guides: two cross head screws (JIS) with plain bearings.
• Rotate the front lens to infinity using the lens sucker through the viewfinder.
• Fix the final position with the three grub screws.

Correcting the aperture

When dismantling I bent a lever of the aperture mechanism.

As a consequence, the aperture row shifts, the aperture closes slightly at the largest opening, apertures 16 and 22 have the same opening.

Click to expand...

I worked on it again.

The apertures were, compared to a second Tokina 35-105, a touch too large.

I was able to correct this by subtly bending the transmissions of the open aperture lever (YELLOW) and the aperture simulator (GREEN):




The two circles show the couplings in the aperture mechanism.

The starting point for YELLOW is to the left in front of the lever:




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