Repairing a Steinheil Auto-D-Tele-Quinar 135mm f/2.8 Lens with Exakta Mount

 

The Steinheil Auto-D-Tele Quinar 1:2.8 f/135mm is a super compact tele lens, made in Germany. This piece was made around 1964/65. It has the legendary "Zebra" look, typical for German lenses of that era, and a fantastic build quality. Optically, wide open, it is at least as sharp as the Meyer-Optik Orestor 2.8/135mm (another highly-regarded legendary lens of that era) - but it has only five aperture blades, as compared to the Orestor's 15 blades.

It seems to be rather rare, but you can always find a few on eBay, where they sell, starting from $70. When I got mine, the optics were in great condition, but the focus was rather stiff and the aperture did not close. Both of these issues should be easy to deal with. From about 20-30 lenses that I work on, a non-functioning aperture was always due to oil on the blades and, as it turns out, this was also the case for this pretty piece (see below). 

There is very little information on this lens on the web, and no repair tutorials. But with some experience on other German lenses from that era, I just gave it a try, and I found that it was pretty. I used the following tools:

• A lens spanner to remove the name plate (one of the first steps), to get access to the front glass element. If that is not needed, you don't need the spanner.
• Quality screwdrivers
• Cotton pads plus lighter fluid (for cleaning the aperture blades) and isopropyl alcohol (I use the 91% version) for cleaning the old grease from the focusing helicoids

The following general rules for lens repairs have worked very well for me.

• In every step, I take pictures and/or draw sketches to remember the orientation of the pieces. For things that you see clearly, a sketch may be more helpful, while pictures also document those details to which you did not pay attention.
• Immediately after separating a piece, I try to understand how it was connected, and I try to immediately reconnect it again before proceeding further.
• Whenever I remove a piece, I clean it and all newly accessible surfaces immediately with cotton pads and isopropyl alcohol, so I have not dirty/oily pieces in my storage container. For small part (screws, springs, ball bearings) I use a storage box with dividers.

I start, removing the back piece which is held by these four screws.

This lever on the back piece is responsible for stopping down the aperture (I recommend to play with the stop-down button and the A/M switch on the back piece to understand the mechanism). In this case, I see that this lever works fine. 

The lever sits in the marked slot which can be moved by hand - or with a wooden tooth pick. Doing so, openes and closes the aperture. So, I see that the aperture itself does work - the problem is only that the oily aperture blades have too much resistance, which the lever can't overcome. This was everything on  the back side, now we turn to the front side of the lens.

I recommend to read everything, because you may not need to do some of the first steps - which I only found out later.

To get access to the front glass (and only for that!), the name ring can be removed using a lens spanner. Be careful, since after removing the ring, the front lens will fall out! If you don't need to access the rear of the front glass, don't remove the ring!

The front part of the lens can simply be unscrewed by hand.

These are the pieces from the front that I have so far. At this point, I cleaned the front glass, put it back, and fixed the name ring.

At this point, you get access to the aperture, and you could start cleaning the blades (which I did - but which would be much easier a few steps ahead).

Now, I removed the three screws (but it turned out that loosening them would have done the job).

 

Then the front part can be unscrewed by hand.

Before removing the focus ring, make sure that it is set to a well-defined position - I picked infinity. After loosening the four silver screws it can be removed. 

I made sure, not to rotate the messing piece, before using a screwdriver to make a little scratch (2.), to note the infinity position.
While normal screws have a single entry point, the focusing helicoids have multiple entry points. For the correct reassemble of the lens, it is therefore crucial to remember the correct one (otherwise, you will not get infinity focus). So, in the next steps, it is critical to proceed very slowly, making sure to document when the pieces separate.

When the messing ring is turned counterclockwise (as seen from the front), the black helicoid (which is guided by two "helicoid keys") moves to the right. But only up to the point where the helicoid keys exit the slots - then it will turn together with the messing ring. It is very important to note where exactly this happens. So, I turn the messing ring very slowly - and take this photo, exactly at the point where the black helicoid piece exits the helicoid keys (the keys can be seen from the back side). For my lens, this happens, when my mark on the messing ring is between the "16" and "22" on the DOF scale.

Then, I hold the messing ring, and turn the black helicoid clockwise (as seen from the front), and note where exactly it exits. 

It exitsa after almost half of a turn, and it turns out that somebody else has already marked this position: It exits exactly when the slot, marked with an "X" is at the place where the messing ring has another scratch. If your lens does not have marks like that, make some (and make sure that you will later not confuse the two slots)!

The black piece actually consists of two pieces (which I discovered accidentally). By pressing on the left side...

...the two pieces separate. Now, the  helicoid and the aperture can be cleaned separately.

I am not a big fan of disassembling apertures, and whenever possible, I try to get away with cleaning the aperture in place. For this, I use the cotton swabs soaked in Zippo lighter fluid and move them, following the orientation of the aperture blades - in this case: clockwise. After moving the soaked swab in circles, wetting the blades, I use the aperture lever to open and close the blades, so that the fluid reaches all the internal parts.

To clean the aperture, it is very important to discard the dirty cotton swabs and repeat this over and over, until no more dirt is visible on the cotton swabs (the picture shows just a fraction of the cotton swabs that I used for this lens). As you proceed, you may notice that the aperture lever moves with less and less resistance.

I turn the messing ring back to where it was at infinity when I made the mark (approximately half a turn clockwise, as seen from the front). From there, I first turn it clockwise to see how far it can be turned before it stops (just to have a reference for later). This happens after approx. half a turn.

Then I rotate it back to the infinity position, from where I turn it clockwise until it exits. For my lens, this happens after about 12 1/3 turns.

I have no pictures of cleaning both of the helicoids. Just a few words: I start removing the big chunks of old grease with wipes or cotton swabs - and then use the cotton swabs with lighter fluid to clean them really well.

Here are all pieces of the lens as far as I disassembled them (except for the screws), everything nice and clean!

When putting the aperture piece into the helicoid, the little metal pin (yellow arrow) needs to sit in the slot.

First, the messing piece is lubed and inserted into the piece with the aperture ring. I am very carefully applying the helicoid grease. If you find that it has to much resistance, better remove some of the grease. I removed and inserted the messing piece multiple times before I was happy with the amount of grease and the way that it rotates. Then the black helicoid piece is lubed and inserted into the messing piece (again, iterating this until the amount of grease seems right) - while inserting this piece, make sure the aperture ring is set to 32 (it took me a while to figure out why the helicoid could not be inserted, until I found that it hit a piece from the aperture ring). For both helicoids, starting from the point where it exited, and back to the original position. The black helicoid is inserted and rotated back to where it started to turn freely (see above). At that point you should look through the back of the  lens to ensure that its slots align exactly with the helicoid keys. Then, carefully turning the messing  ring will cause the slots to "catch" the helicoid keys, and it will start to move back and forth when turning the messing ring.

 

After the helicoids are back in place, I reassembled the focus ring (make sure that the scratch mark is at infinity, and aligned with the ring's scale).

Screw in the next piece, and fasten the three screws.

After inserting the front glass element, the front of the lens is complete.

Reassemble the back piece such that the lever sits inside the slot.

And that's it. Quickly check that the aperture works (in "A" position it should close when pressing the silver stop-down button; and in the "M" position, the aperture should follow the value set on the aperture ring). Mine did! And it is great to see the beautiful lens with a working aperture and a smooth focus ring, looking forward to new photographic adventures!

More of my lens repair tutorials can be found here. 

Repairing a Meyer-Optik Görlitz Domiplan 50mm f/2.8 Lens

The Meyer-Optik Görlitz Domiplan 50mm f/2.8 lens is a simple triplet. It used to be the inexpensive "kit lens" for Praktica SLR cameras, and it's still liked by some for its special rendering and its "Soap Bubble" bokeh. It has a fully automatic pressure diaphragm, meaning that the aperture closes whenever the stop-down pin on the rear is pressed. This also means that if you want to adapt it to a mirrorless camera, you need an adapter with a "lip" that presses this pin (otherwise, you can only use the lens wide open). Fortunately, those adapters are readily available, and they are cheap ($12 on eBay).

Unfortunately, many of the of the available Domiplan lenses have at least one of two problems:

• The focus is stiff - sometimes extremely. This is due to the old grease in the focusing helicoids becoming sticky.
• The aperture  is not working, i.e. the aperture is wide open and pressing the stop-down pin has no effect. This may be caused by oil on the aperture blades or by a disconnected mechanism in the back piece.

In any case, if you own a Domiplan lens, it's helpful if you know how to clean and fix it. Overall, this is relatively easy. What you need is:

• a rubber tool to remove the front ring (see the first step), although you maybe able to improvise here
• quality screwdrivers
• cotton pads plus lighter fluid (for cleaning the aperture blades) and isopropyl alcohol (I use the 91% version) for cleaning the old grease from the focusing helicoids

The front piece with the name plate is extracted using a rubber tool. 

For older version, this piece was made of metal (left) while later it was made of plastic (right).

As a general rule: whenever you remove a piece, clean all surfaces with isopropyl alcohol using a cotton swab.

After it is removed, the aperture ring (with the simple spring) can be taken off. But watch out so you don't loose the tiny metal ball on the aperture ring.

The back ring can simply be unscrewed by hand.

The next step is to loosen the three screws in the piece below. Watch out for the two springs!

Before removing the springs and the metal pieces (which guide the focusing helicoid), be sure to set the focus to a well-defined position (I set it to infinity) and make sure not to change this afterwards.

Removing the next three screws gives access to the aperture blades. So, be very careful when removing these screws and lifting the piece.

The whole piece with the aperture blades sits lose and can be lifted.

Initially, the aperture blades are still in their correct positions (but the slightest touch will make them come off).

Reminder to clean all pieces - there is more oil/grease/dirt than you would imagine. And at the end it's nice to know that your lens is completely clean inside. And in this case, it's absolutely necessary to remove all oil/dirt, to ensure that the diaphragm works well.

Sometimes, you may be able to clean the aperture blades in place. But here, I decided to remove them to get full access and clean everything really well.

I have no pictures of cleaning the aperture blades. But I placed them in a small glass container, filled with isopropyl alcohol. After a little while, I took them out and cleaned them with a cotton swab and lighter fluid. You have to be extremely careful here. If you bend the thin metal of the blades, there is usually no way you will be able to make them flat again - and this ruins the aperture.

With the focus set to infinity, remove the springs and metal pieces (if you have not done this yet).

Carefully remove the focusing helicoid (clockwise, as seen from the front) and remember exactly the position when it comes loose. For my lens, this happened after almost one full turn - and I took this picture, to document where it happened. Unlike regular screws, the helicoid has multiple entry points, and if you insert it wrongly your lens will not focus correctly (you may not be able to reach infinity).

Remove the front piece.

Cleaning.

This looks much better!

This screw is limiting the focus range. Remove it to access the second, fine helicoid. Again: start from a well-defined focus setting (before, I had set it to infinity, and I keep it there).

After removing the focus-limiting screw, I check by how much I can further insert the focus ring. Starting from the infinity position, I can turn the focus ring clockwise (seen from the front) by another approx. 45 degrees before it gets stuck. Then, back from the infinity position, I can turn it about 6 1/2 turns counterclockwise (seen from the front) before it comes loose.

This is where it comes loose.

Cleaning the old grease.

Adding very little helicoid grease.

Insert the fine helicoid where it came loose, and turn it clockwise. In my case 6 1/2 turns - then I check if I can turn it further by the approx. 45 degrees that I noted above - so I know it sits correctly. Now, I turn the ring forth and back many times to distribute the grease evenly. If you hear the sound of metal on metal, you may want to add more grease. If the ring turns with too much resistance, take it out and remove some of the grease. Better iterate this a few times, since this will determine how smooth your lens will focus.

Insert the focus-limiting screw.

First, I make a "dry-test", to see if I can insert the coarse helicoid exactly as it was before.

Then I add helicoid grease, and insert it .again. Again, I rotate it back and forth, to distribute the grease evenly.

 

I set it to the infinity position (aligning the holes and the notches).

Then comes the (not-so-) fun part of assembling the aperture.

Adding the first blades is easy...

...but the last two can be painful. For me, it helps when I move the aperture pin carefully in and out. When doing this for the first time, it may take a while. But eventually, you get a feeling for this.

Once the last blade sits in its place, carefully close the diaphragm (using the long pin) by a small amount, and cover the aperture with the back-glass element. (If you leave it full open, the back element may touch some of the blades, displace them, and force you to go back to the previous step - and you don't want that!!)

Before inserting the metal pieces (the helicoid keys), add a little grease to them...

... and also to the slots in which they move.

Then you insert the springs.
At this point, you should try to understand how the aperture stop-down pin on the back of the lens connects to the long lever inside the lens to stop down the diaphragm. Otherwise you may not be able to put the back piece correctly back.

Look at the back piece (the right one in the above picture): The aperture stop-down pin on the back of the lens can move the "little piece" (I don't know what to call it otherwise) to the inside. The pressure from the diaphragm lever (left piece) will push it back. So the "little piece" has to be in the up position, so it can connect to the long level from the diaphragm. 
Before inserting the two springs, try to connect the two pieces, such that pressing down the aperture stop-down pin will close the diaphragm.

If you thought that the reassembly of the aperture was the worst part, you were wrong. The worst part comes now. You have to insert and press the two springs while adding the back piece as practiced in the previous step. I think that this is an awful construction, since this is hardly possible. It's easy to bend the springs while doing this.

Eventually, yo may succeed. Again: check that the stop-down pin works!

The rest is straightforward: Add a little grease to the spring in the front, place the metal ball in its hole and insert the aperture ring (test that you can rotate it from 2.8 to 22 and that it clicks correctly).

Insert the front ring...

...and the back ring...

And here is your Domiplan lens. As good (or as bad...) as it was when it came from the factory, a long long time ago.

More of my lens repair tutorials can be found here.