Rokkor 50 1,2 disassembly?

V�sen · Joined: 06 Sep 2011 Posts: 38

Hi, and sorry for cross-posting (I've queried about this on allphotolenses and dyxum, close to a week ago, no answer so far) but if I get a reply here I'll cross-post that too : )

The 58 1,2 and 1,4 each seem to have one or several disassembly guides but I've yet to come across anything of the kind regarding either version of this lens (MD Rokkor or MD) so perhaps someone herearound knows?

The question is because the focus ring, while fully turnable, occasionally meets a bit of friction, almost like a bit of grit or half-dried grease and I'd like to try and fix that. Preferrably not without some sort of guide, though.

Optically I kind of love it. It is perhaps generally considered a troll with warts according to the Hymn-to-the-58-1,2 but I think it's great and preferrable to the 58 1,4 that I also have. (Unless uniform sharpness across the frame wide open is the goal)

V�sen · Joined: 06 Sep 2011 Posts: 38

No reply at any venue. I suppose no one has disassembled this lens and lived to tell the tale? :p

I would try it based on my experience with the 58 1,4 but there's a mismatch on the first step: at the front, the "text ring" (which sits at the top) does not have a groove for turning, only the one underneath does. With the 58 the top one has a groove, logically enough. It may be that they are one and the same in the 50 1,2 but I daren't attempt to turn it via the lower groove in case that ring is a different ring from the text ring above.

Here's a wide open 'flowers, typically..' shot:

Whereas the 58 1,4 is a bit "gray" wide open this thing has life, I think.

edit.

Here's another one which I related to the Rokkor pool in Flickr(so you may have seen already):

I love how something appears to have 'gone wrong' in the background Smile

Lloydy · Expire: 2022-01-01

Could the text ring spring out ? some Canon rings are like that.

I like the second picture, the lens is worth saving. Wink

V�sen · Joined: 06 Sep 2011 Posts: 38

Thank you for your reply.

How would I attempt to make it spring out do you mean, via prying somewhere along the side or trying to turn the lower ring, if indeed it is a separate ring, via its groove?

Shan't try it until I find a grease that works at any rate. Have tried a version of Tri-flow bicycle grease and another of Super lube, the first was too slow and the other too light.

Gardener · Joined: 22 Sep 2013 Posts: 950 Location: USA

It looks not unlike rokkor 50/1.4 and probably comes apart the same way - that's unscrew name ring (whatever you do, do not try to pry it out), remove the flange, unscrew front lens block, remove focusing ring, pop out aperture block, remove mount, unscrew rear lens block, probably remove helicoid guides, remove helicoid.

koji · Expire: 2012-12-27

That ring is normally called "name plate" or "bevel", not "text ring".

MD 50/1.2's name plate wont come off like the other lens, see this

Just unscrew that (at yellow arrow) tiny screw, the filter frame comes off. You have to rotate it.
The rest is more or less same as what Gardener says.

good luck.

V�sen · Joined: 06 Sep 2011 Posts: 38

Thanks for enlightening me Smile

I also found a source of helicoid grease thanks to this forum so no more experimenting with lubrication oils or bicycle grease..

I'll use the lens a bit more and if the intermittent friction bothers me I'll try the disassembly.

Gardener · Joined: 22 Sep 2013 Posts: 950 Location: USA

V�sen · Joined: 06 Sep 2011 Posts: 38

Gardener · Joined: 22 Sep 2013 Posts: 950 Location: USA

I did both with Super Lube, the grease kind, but I'll probably redo one of them with regular NLGI 2 white lithium.