Kowa Set Aperture Blades help

[Malinku]

So I recently picked up a Kowa Set. to my amazement the shutter and light meter are in fully working condition. This is my lottery win instead of the cash.

The only issue is that the aperture blade are stuck. I'm wondering if anyone has the info on how to get to the aperture blades on this camera. All I know is that I will have to get the lens off the shutter. I would assume the three visible screws on the lens by the depth of field scale would be a good place to start.

Any info would help.

 

[shutterfinger]

Standard leaf shutter build is Aperture blades and adjustment lever/ring at the rear of the shutter case; shutter blades; timing, flash, setting, release mechanisms; front cover.
With the lens removed, shutter locked open on B, and back open an aerosol cleaning agent such as CRC Quick Dry Electrical Contact Cleaner available at some auto parts stores, some hardware stores and Home Depot can be sprayed into the aperture blade opening. Allow to dry some then try the aperture ring. If it is a mechanical failure you will have to disassemble the shutter.
This you tube video may be of some help. https://www.youtube.com/watch?v=70bsJvc2ANU

 

[Malinku]

From the looks of it the aperture system is in front of the shutter on the kowa set. So it is an oddity of a leaf shutter.

 

[Kirks518]

It sounds like it's similar to the Kodak Retina design; leaf shutter in body, then comes the lens; then some elements, then the aperture blades, then some more elements.

I need to preface the next with the fact that I've never worked on a Kowa lens.

Typically, the aperture blades are closer to the rear elements, but taking a lens apart from the rear usually involves springs and levers, so it is more difficult. So I will almost always go in from the front. The beauty ring (the ring with the lens info on it in the front) is usually screwed in, and needs either a spanner wrench or a rubber stopper (big enough to cover the ring) to unscrew it. After that, you can usually take out the elements or groups of elements to get down to the aperture assembly. Once you get to that, you can either use the electronics cleaner or lighter fluid to (hopefully) free up the blades. The other option is to remove the aperture assembly and clean each blade individually, but this will most likely require a (near) complete teardown of the lens.

Most of the time the lighter fluid/electronics cleaner gets the job done. It takes a whole lot of either, and quite a few cotton swabs to remove the oil/lube, and to completely clean the blades. Whatever fluid you use will get on the remaining lens elements, but doesn't hurt them (at least that I've ever noticed), and cleans up pretty easily.

This is probably a good lens to learn on, as they aren't very valuable.

 

[Malinku]

@Kirks518 Thanks for the info. Yes it is designed like the Retinas. I'd say going in from the front would be best as I don't want to mess with the shutter at all (since it is working properly).

As the back just has the shutter, mirror/"film door".
https://flic.kr/p/D1hWGt

Front has the lens and aperture blades.
https://flic.kr/p/CARpBD

 

[Malinku]

Got the lens apart but I messed up the aperture blades and now that are out of position. I can seem to be able to get the lens apart enough to be able to put the aperture blades back into position.

So at this point I'm looking for a lens that works or a professional that knows how to get it apart.

Here is where I'm stuck at. All I can do is get the small inside element off and see the aperture blades being missed up can't fix them from there.
https://flic.kr/p/CgsGxX
this how they currently look.
https://flic.kr/p/CgsFRB

 

[shutterfinger]

1. Put all the photos of this repair inquiry in a album leaving it public or make it private then post the link to the album in this thread. Name it Kowa seT. As you currently have linked to the photos in your photostream one cannot scroll through the images relevant to this inquiry without getting unrelated images and advertising making it a PITA to try to figure out.
2. What camera are you using to take the camera/lens photos with, just curious.
3. Take and post photos of the lens with the bad aperture to include 1/8 inch-1/4 inch area outside the outermost edge of the lens barrel both front and rear as well as a flat side view. Use something non distracting to prop the small end of the lens up with.

4. I suspect you will have to remove the lens elements from the lens barrel to access the aperture but having never seen one of these cameras or its lens it is impossible to tell anything about disassembly with the information provided. Google photos don't quite tell the story either. Guessing a pivot pin has broken off or come out of the slot it moves in.

Looking at some google photos https://www.google.com/search?q=kow...VB32MKHdYbDLkQsAQIIw&biw=1920&bih=971#imgrc=_ it looks like some 50mm lens have a 2 notches in the outer edge of the front beauty/retainer ring 180° apart. If yours is similar then a spanner that fits the notches is used to unscrew the retainer ring then the lens element(s) slide out the front. The retainer ring may have a clear threadlocker. Acetone aka nail polish remover will dissolve it. I cannot guarantee removing the lens elements will give access to the aperture. Your side view suggests the lens barrel separates at the black and silver aluminum threaded section.

 

[Kirks518]

Umm... you took out the lens assembly, and removed the assembly from the focusing helicoil (or however you spell/say it). Putting that back together correctly will be a fun experience.

What I was suggesting you do above is what shutterfinger talks about in point #4. Basically, you should leave the lens barrel parts where they are, and only remove the lens elements. Removing elements should only require the removal of retaining rings, and the front beauty ring (which is the black front-most ring with all the lens info on it). When you remove that, you can get the first element out, then there should be a retaining ring for the next element, etc., etc., until you have access to the blades.

From the looks of the linked photos, it looks like all you've done is removed the complete lens element assembly from the lens body.

 

[Kirks518]

Remove ring #1 by unscrewing with a spanner in the 2 slots (circled)

Remove ring #2 in same manner. If no slots, you a rubber stopper

That will allow removal of the front element (#3)

Continue until you get to the blades

 

[Malinku]

@(there was a url link here which no longer exists) thanks