Overhaul of Contax Planar 1.4/50mm T* MMJ

BRunner · Joined: 29 Jul 2009 Posts: 705 Location: Czech Republic

I've got this lens with oily aperture and stiff focusing ring, but with good optics. So complete overhaul was necessary.
For someone who knows what he does. Photos are self explanatory I hope.

Remove the front and rear optical group first to avoid scratches.

As usually only assembling. Disassembling is just reverse process.

Fix the aperture with three screws in plastic ring

Fix the aperture/optical block assembly with three screws

Adjust infinity on camera and fix it with focusing ring

Put back name plate ring

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nyoszi · Joined: 13 Sep 2011 Posts: 10 Location: Hungary

Hello BRunner, how did you unscrew the nameplate in the front? I usually do it with a smaller cap, it worked with flektogons or pancolars, but doesnt work with this one.

I also tried to open the rear part, I got stuck pretty fast, I unscrewed everything I could, but it seems like a screw is holding it from the inside. (its on the opposite side of the red dot, I can only see the end of it, in the thread)

Thanks for you help!

nyoszi · Joined: 13 Sep 2011 Posts: 10 Location: Hungary

http://www.flickr.com/photos/67470780@N04/

BRunner · Joined: 29 Jul 2009 Posts: 705 Location: Czech Republic

The nameplate ring is one piece with filter mount, as you can see on last image. Just unscrew it, it is probably glued, you need to use some force.
The rear part of AE version is slightly different. Maybe there is ring over rear part of lens like on Rollei Planars.

Orio · Expire: 2012-12-04

BRunner, thanks much for sharing this very detailed report.
I will never have the guts to do that myself on one of my lenses, but for people who dare,
this is certainly going to be extremely useful!

nyoszi · Joined: 13 Sep 2011 Posts: 10 Location: Hungary

Thank you, I finally managed to unscrew the nameplate, and the rest was easy!
D�ky!

downtwnfb · Joined: 14 Feb 2012 Posts: 1

This is still a wonderful thread. Thank you for this thoroughly photographed post of the 50mm/1.4 reassembly. I have a 50mm/1.7 and can't seem to remove the nameplate. I'm guessing that they have similar design so I tried grasping the outer rim with a rubber mat and turning firmly counterclockwise, there is now some light play, but not a full release. I'm hesitant to go any further without some sage advice. I also know that I do so at my own risk. Any further guidance would be appreciated.

BRunner · Joined: 29 Jul 2009 Posts: 705 Location: Czech Republic

1.7 Planar is different. The nameplate ring is screwed inside filter ring and it holds front lens in place too. I can look later.

flusi100 · Joined: 21 Feb 2012 Posts: 1

After removing the name plate and the three screws I have problems pulling the focus ring off. It is loose and can be lifted a bit. But it seems at the inside of the focus ring a hook is preventing to remove it.

Any idea what to do?

mtjade2010 · Joined: 11 Apr 2012 Posts: 4

BRunner · Joined: 29 Jul 2009 Posts: 705 Location: Czech Republic

BRunner · Joined: 29 Jul 2009 Posts: 705 Location: Czech Republic

mtjade2010 · Joined: 11 Apr 2012 Posts: 4

mtjade2010 · Joined: 11 Apr 2012 Posts: 4

I finally put all my courage together and worked on my Contax Planar 50mm 1.4 MM version yesterday. It had oily aperture blades and was completely stuck at fully open aperture.

I used a rubber strap wrench and it was easy to turn the front barrel counterclockwise to take it off. The front group of glass wasn't too tight. I was able to just use my finger to turn if counterclockwise and took it off too.

When I tried to remove the back end of stuff I had a problem. One of the 3 screws that hols the bayonet mount plate was so tight that I ruined it. I had to use a micro drill bit to drill off the head of the screw and took the plate off.

The rear group glass also went off without too much trouble. Taking the aperture mechanism off was a challenge. It wasn't obvious where to unscrew in order to get things off. Finally figured it out and the the blades all fell out. After cleaning off all the oil on them it was even more challenging to put them back together. Had to practice many times without the blades before doing it with actual blades included. Assembling the helicoil was quite a challenge too. Took me a few hours to figure out the trick to do it quickly.

Finally I succeeded and adjusted focusing and everything seemed to work properly except that I now have only two screws to keep the bayonet mount plate on the lens. I mounted it on my RTS-2 and it was still firm and tight. I will need to keep in mind that it is not as secure as it was. It looks like will not affect the performance of the lens.

The only thing that I am not exactly happy, besides breaking one of the 3 screws, is that now I can see some tiny dirt on the surface of the glasses inside and out. I used a blower to blow off as much as I could still the glasses are not as spotless as they used to be. I don't want to wipe it with anything. It would only get worse not better. It's still much better than a Planar with frozen aperture. The blades are now clean and snappy. I will try to shoot some Velvia 50 with it soon.