Need help opening filter rings.

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Cableaddict
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p.2 #1 · Need help opening filter rings.

JimBuchanan wrote:

If you look at the photo, there is a blurry screw going into the side of the "black piece" on the left. That is one of 3 screws, which when unscrewed, will release the entire "black piece", which again, has the filter threads.

Back to the nomenclature issue: Perhaps THIS piece should be called the "filter ring?"

So then we'd have:

1: The name ring, removed with a rubber stopper.

2: The retaining rings, which hold the front lens-assembly in place and are removed with a spanner.

3: The lens-assembly itself. (on this lens, composed of two elements)

4: The lens-assembly ring (??) which holds the assembly together, and not to be confused with the two (slightly larger) retaining rings.

5: The filter ring, which is attached to the main helical gear assembly with three screws on the side.

Works for me.

Sep 17, 2009 at 06:12 PM

JimBuchanan
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p.2 #2 · Need help opening filter rings.

Cableaddict wrote:
C,mon, fellas, play nice!

OK. Done.

Cableaddict wrote:
On the two 58/1.2's I've opened so far, which are both early ones (ser 250xxx) you cannot get to those screws until the front assembly is removed. Additionally, I completely disassembled these two lenses, without ever removing the name rings. I can even see the infinity-stop screws.

I have a feeling (not sure yet, of course) that these versions are mechanically different from the later ones, which may account for more than a little of the confusion here. (I see a related question on your infinity-adjust routine, but will address that later, when I'm sure)

I've certainly learned to never say never, but how do you adjust the infinity focus screws if you don't take off the name ring of the Rokkor 58/1.2?

Anyway, after converting the bayonet to EOS, and the lens then needs adjusting for infinity or cleaning, the first thing I do is unscrew the name ring. Sometimes I do this even before I convert it to EOS, just to have it loose.

With the name ring removed, the infinity adjust screws are visible. I can then turn the focus ring out to minimum focus and the 3 side screws appear. The 2 main reasons to remove the filter ring is if you wanted to unscrew the front lens assembly to clean the inner surface or if you wanted to release the aluminum helical from the aperture cup for cleaning.

Sep 17, 2009 at 08:46 PM

Cableaddict
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p.2 #3 · Need help opening filter rings.

JimBuchanan wrote:

I've certainly learned to never say never, but how do you adjust the infinity focus screws if you don't take off the name ring of the Rokkor 58/1.2?

Seems I just had a brain-fart. (I'm a bit too young for a "senior moment")

I can adjust those screws without removing the name-ring, but only because I have the front elements out. (DUH...) It would be pretty hard to adjust for infinity this way!

-Sorry.

Sep 17, 2009 at 10:24 PM

pengland
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p.2 #4 · Need help opening filter rings.

I have only worked on 3 or 4 Rokkor 58mm 1.2 lenses. These were 200xxx or 250xxx series lenses. For the life of me I could not find a parting between the "name ring" and the focusing ring. The whole thing seemed to be one piece and I was not prepared to apply a huge amount of force to attempt to separate them. Adjusting the infinity adjustment screws is still possible but a bit of a PITA.

The way I did it involved dis-assembly between each adjustment. This is how I gained knowledge and experience with the separation and reassembly of the internal and external rotating parts of the helicoid. Without the name ring removed it is the only way to get at the infinity adjustment screws without messing with the front elements that I could find. After doing it a few times with everything marked it only takes me about 10 min to do the dis-assembly, make a slight adjustment and reassemble the lens, test and repeat.

For the very first Rokkor (200xxx series) I worked on I used Jim Buchanan's conversion kit. The spacer was so accurately machined for thickness that I only had to make two tiny (a fraction of a millimeter of angular movement) adjustments as described above to get the lens adjusted to infinity.

Sep 17, 2009 at 11:08 PM

JimBuchanan
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p.2 #5 · Need help opening filter rings.

I am glad to here the spacer is so close to correctness.

But, really, that name ring does come off all Rokkor 58s. The parting is there. On the rubber focus ringed version, with the rubber grip removed, you can see a difference between both sides. The earlier ones have the same construction.

If you run into a stubborn one, acetone should dissolve almost any guck or glue, etc. It evaporates quickly so run a small stream around the junction, apply the rubber wrench for a good grip and twist CCW. On later lenses, remove the rubber focus grip so as to not degrade the rubber with the acetone.

Sep 18, 2009 at 12:46 AM

pengland
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p.2 #6 · Need help opening filter rings.

JimBuchanan wrote:
I am glad to here the spacer is so close to correctness.

But, really, that name ring does come off all Rokkor 58s. The parting is there. On the rubber focus ringed version, with the rubber grip removed, you can see a difference between both sides. The earlier ones have the same construction.

If you run into a stubborn one, acetone should dissolve almost any guck or glue, etc. It evaporates quickly so run a small stream around the junction, apply the rubber wrench for a good grip and twist CCW. On later lenses, remove the rubber focus grip so as to not degrade the rubber with the acetone.

That's a great tip Jim! I am going to have to bite the bullet and do it that way in the future. That would be much faster and much less invasive.

Sep 18, 2009 at 01:00 AM

Cableaddict
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p.2 #7 · Need help opening filter rings.

So Jim, how do you get the rubber clamp to hold onto the name-ring? There's only about 1mm of edge. I tried with a wrench similar to what you show in the adjustment tutorial, but it won't grab on, it just bends in onto itself. Hmmm. Maybe a vise with hard rubber glued to the jaws...

I imagine it might be easier on the later lenses, with the rubber grip removed, as there would be a larger edge to grab. -but that raises another question: How do you safely remove the rubber grip? Just pry it up with a screwdriver?
I would hate to damage one, because this material doesn't seem to be available online, even from Micro tools.

================

BTW- Regarding the name-ring on Zeiss lenses (and a few others) which do not lay "on top" of the retainer rings:

I had asked earlier about how to remove them. Paul had a decent suggestion of using a roll of packing tape, un-rolled to the proper diameter. While this sounds viable, I found a much easier way: I took one of those hollow, black-rubber ring tools from Micro tools (the $18 set) which was a little smaller than the Zeiss's filter diameter. then I simply squeezed it together, forming an oval shape. This pushed sideways against the name-ring, and it twisted right off.

Sep 18, 2009 at 03:46 AM

JimBuchanan
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p.2 #8 · Need help opening filter rings.

Cableaddict wrote:
...how do you get the rubber clamp to hold onto the name-ring?

How do you safely remove the rubber grip?

I know its a slim shoulder, but I don't use the handle part of the rubber wrench, I grasp the 1/2" rubber band with my left hand to keep it in position and distribute the torque evenly, and grab the focus ring with my right hand and twist.

I use a metal probe or thin screwdriver shank to separate the rubber grip from the focus ring as there could be an adhesive, then slip it over an inch at a time, off the focus ring.

Sep 18, 2009 at 03:59 AM

Cableaddict
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p.2 #9 · Need help opening filter rings.

Excellent info, Jim.

Thanks.

Sep 18, 2009 at 04:19 AM


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