Asahi Super Takumar 200mm f4 repair guide

Unlike smaller Asahi lenses, the Super-Takumar 200/4 is a rear-entry lens. This means that it is not necessary to remove the name plate around the front element of the lens to gain access to the aperture blades, focussing ring and the aperture control lever. It is necessary however, to remove the front name plate in order gain access to the first three lens elements in order to clean them. This guide will show how to gain access to various parts of the lens.

For the disassembly of this lens, you will need:

• A rubber glove (or some sort of item to provide friction for turning)
• The front cap of a 49mm filter sized Takumar (35,50,55,135mm etc). This is for inserting in the front ring of the lens to remove the name plate.
• .9/1, 2 and a 3mm flat head screwdriver. A standard cheap precision set should be all you need, i.e. the ones you find for $10 in a hardware store.
• Lighter fluid
• Super-lightweight grease. Usually found in a bike store, it has to remain in its place and not turn into liquid in hot temperatures.
• Possibly some acetone (or nail remover) if the screws are glued in place.

This guide is separated into two sections because you can do either without affecting the other. It provides general information on disassembling and reassembling the lens. Hopefully it provides enough information to understand the general concept of how to disassemble and reassemble this lens.

1. Front Section (front three elements to clean off fungus etc)
   
2. Rear Section (focussing unit, aperture blades and the rear element)
   

Eventually, this guide will be available as a PDF in its entirety. If you need one now, email me.

FRONT SECTION:

There are three elements in the front section of this lens. It’s essentially a question of twisting to access them and there’s no need to disassemble any other part of the lens. Focus the lens to the smallest distance, so that it’s the longest. You’ll see a front section to the lens, you’ll see the connection line in (p). You’ll probably need to put rubber gloves on, grip the front section and the section below the front section but above the focussing ring and twist until it comes off (q).

 

p) red circle showing the connection       q) front section detached

between the first and the main section

Now you’ll have the front two elements completely detached and the 3^rd element still on the main part of the lens. To get in between the 1^st and the 2^nd element, you’ll have to remove the face plate. To do this it will be extremely handy to have the lens cap off a smaller Takumar (35/50/55 any one with a 49mm thread). Basically you want to use the inside part of the lens cap to turn the face plate off, you’ll notice it fits in perfectly. To do this you’ll need a bit of rubber get enough friction to turn it off. You can put the lens cap in your rubber glove and use that if you want, but any bit of rubber big enough should do.

Once the face plate is off, the 1^st element is not held in by anything, you’ll have to tap it out or jerry it out with a screwdriver or something (be careful). But it should be enough to just tap it out.

Now you can clean both sides of the 1^st and 2^nd element and the front side of the 3^rd element. I have never needed to access the rear part of the 3^rd element but I suspect you twist off the black ring around the edge of the 3^rd element and then you’ll be able to tap it out like the 1^st element.

Everything goes back easily in reverse order, make sure the 1^st element is completely in, it should twist freely once in.

 

REAR SECTION:

You'll need to understand generally how the super-takumar (or other manual lenses) are put together and how they work. This is important as putting the lens back together is a little tricky and will probably require some initiative and knowledge of how the system works. Below is how to dissasembly the lens, take care as it's basically a reverse order for re assembly but you'll need some trial and error to get the right barrel length for focussing. You can email me if you need some help with re assemblage, I would like to write more in re assemblage when I get time.

Firstly, focus the lens to the smallest distance (longest physical size), this will give you a lot more room to work with later on. Now locate and remove the three screws in the focussing tube as pictured (a), the screws will look like this (b).

a) a screw on the focussing ring             b) the screw

Remove the three very small screws that are on the DOF ring above the aperture ring (c), the screws will look like this (d).

 

c) the small screw d) the small screw

Slide both the focussing ring and the DOF ring upwards, this will reveal a single screw that sits just above the aperture ring (e). BEFORE removing the aperture ring it is important to note there is a small ball bearing that locks each aperture in place (making that click sound), it is located underneath the aperture ring (f). Make sure you slowly slide the ring up and cover it with your hand, as this ball bearing can pop out quickly and if you lose it you'll be spending a bit of time trying to find it.

e)                                                         f)

Now you can shift the aperture ring upwards with the focussing ring and the DOF ring. This will give you access to the bottom part of the lens, the aperture control lever unit/screw mount. Locate the three screws connecting this section to the larger lens unit. There are two sets of screws on this unit, a small set closer to the screw mount, and a larger closer to the front element (g - in red). The three screws will look like this (h)

g)                                         h)

Now you can gently remove this unit from the lens unit , be careful not to be toorough (i). Afterward you can remove the DOF ring and the aperture ring (j).

i)                                         j)

Now, holding the lens unit facing downwards and looking through the lens, you’ll see the aperture lever, and two tracks running downwards with two units screwed in that run up and down the tracks (k). Unscrew these two units, they will look like this (l).

k)                                         l)

Now the lens unit can be unscrewed, there are three separate parts to the lensunit, it should be easy to unscrew them, they are hooked together logically (m).

m)

The unit furthest on the right in (m) is important for the focussing. You candismantle it further into another three units (n), these units are the ones you need to clean and re-lube (n), you should also clean and lube the much larger track seen in (m) that runs into the track seen in (n), on the inside of the brass ring

n)                                         o)

Now you've taken the lens completely apart, everything goes back the reverse order but care should be taken to get the right length of the barrel so the focussing ring fits in nicely with the DOF and aperture rings and can still focus to infinity. One important thing is that when putting the things in (k) back on, the rail closest to the aperture lever is the on with the screw hole on the right hand side of the rail. If you have big difficulties, email me. I'll try in the future to put a document together detailing this, but it may take some time to find the time.

(source: David Image Photography )