All the narrow MM lenses tested are identical inside, so the following instructions will work for all of them.
 |
These instructions are for the MM lenses only. This is the Carl Zeiss MM Distagon 35mm F2.8 |
 |
First, I would take a picture of the bayonet, so it will be easy to rebuild later |
 |
Some lenses have this curved piece here, we have to remove it. This one is the Sonnar 135mm. |
 |
Now, unscrew the three upper bayonet screws. Use a good screwdriver, not those cheap ones from hobby shops, these screws are glued to the threads and it is necessary to make enough pressure and turn them carefully. |
 |
And remove it. |
 |
Now, unscrew the bayonet. |
 |
And lift the diaphragm ring together with the
bayonet. Caution! Have the aperture ring in a middle position before lifting it, and lift it vertically without twisting it while lifting it, to avoid moving to the extreme side the internal iris mechanism, which could be difficult to put again in its place. |
 |
Ok, it's better to cover the lens meanwhile we are working on the ring. |
 |
Now, we have to put the bayonet apart from the ring. |
 |
When they are apart, look for the bearing ball, it should be near its place, over the small spring. |
 |
Now look at this spring, we need to uncouple this
side
from the hook. Usually, there is a bit of glue to secure it, don't pull the spring, it can be deformed or broken, just scratch patiently the glue with a pointed tool or a needle. |
 |
The spring is free now. |
 |
With the plastic tool, lift a bit the steel ring. |
 |
And push it to the right, so it can be removed from the Contax bayonet. |
 |
In
case the steel ring doesn't move to the right, it means it got glued
just under the square slot. This
is because they dropped glue over that screw and some glue went under
the steel ring. Also could be glued around the round holes, from the
bayonet screws. So we need to remove that screw and the square piece that it attaches . |
 |
Now, to unglue the steel ring, use the plastic
tool to
avoid scratches. Put it like the picture and turn it. Please don't try to remove the steel ring lifting it by the opposite side, you will bend it. |
 |
Put
the diaphragm ring on the lens, you will see a lever inside that
commands the blades, which goes inside this u shaped piece of clear
metal. Now you must be able to open and close the diaphragm rotating the ring. |
 |
Put a little bit of the special grease on this small spring, so the bearing ball will get sticked to it. |
 |
Bring the small ball to its place , better don't use tweezers , the tip of your screwdriver with some special grease will not lose it, |
 |
And the ball on the spring, leave an small amount
of
grease on the ball. |
 |
Now it's time to put the steel ring, notice the hook goes downwards. |
 |
And this square slot goes here. |
 |
Turn slightly the diaphragm ring so the small ball will coincide with one of oval shaped holes. |
 |
Another view of the small ball and the steel ring on it. |
 |
Here you can see all is in correct position, the small ball, the round hole for the screw and the square slot. |
 |
And the rest of holes too. |
 |
So we can install the new Pentax bayonet, be careful now, first find the correct position looking at the red dot, it goes in front the lens scale center. Then check if the screw holes are well aligned, and finally put the Pentax bayonet lowering it vertically. |
 |
You should feel the spring pushing back when you press the bayonet against the lens, in this case you can screw the bayonet and the work is finished. |
 |
So we can use several Zeiss/ Contax lenses on our
Pentax cameras, these
lenses are on par with Leica and the best Pentax Limited . To buy the replacement bayonet, please go to our Contax-Pentax page |