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Topcor lens, help
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PostPosted: Wed Jul 29, 2020 8:21 am    Post subject: Topcor lens, help Reply with quote

Anyone recently open up one of the 3 Topcor lenses that have the arm? 3.5cm, 5.8cm,& 100cm.
I'm about to dig in to my new 3.5cm and it's been a while since I opened up the 5.8cm, and it's not separating like I was expecting, so rather than going in blind, I'm pausing in the hope of get an idea of how both ends come apart, it's in better shape than I thought and don't want to make things worse.
Thanks in advance.


PostPosted: Wed Jul 29, 2020 8:59 am    Post subject: Reply with quote

Unfortunately i have no experience with those variants of the Topcors, but i wanted to say kudos to you, an experienced lens tinkerer stopping and asking for help.

Tomas


PostPosted: Wed Jul 29, 2020 12:54 pm    Post subject: Reply with quote

tomasg wrote:
Unfortunately i have no experience with those variants of the Topcors, but i wanted to say kudos to you, an experienced lens tinkerer stopping and asking for help.

Tomas

I feel like a doctor, do no harm...

"Experienced lens tinkerer" Thanks. 😊


PostPosted: Wed Jul 29, 2020 1:03 pm    Post subject: Re: Topcor lens, help Reply with quote

Lightshow wrote:
Anyone recently open up one of the 3 Topcor lenses that have the arm? 3.5cm, 5.8cm,& 100cm.
I'm about to dig in to my new 3.5cm and it's been a while since I opened up the 5.8cm, and it's not separating like I was expecting, so rather than going in blind, I'm pausing in the hope of get an idea of how both ends come apart, it's in better shape than I thought and don't want to make things worse.
Thanks in advance.

I figured out the front end, a spanner is required under the ID ring, between the filter thread and the optical cell there is a small gap, about an inch deep, at the bottom is two holes for a spanner, too thin for my spanner to fit, looks like Topcon had a ring spanner for that.


PostPosted: Wed Jul 29, 2020 4:38 pm    Post subject: Re: Topcor lens, help Reply with quote

Lightshow wrote:
Anyone recently open up one of the 3 Topcor lenses that have the arm? 3.5cm, 5.8cm,& 100cm.
I'm about to dig in to my new 3.5cm and it's been a while since I opened up the 5.8cm, and it's not separating like I was expecting, so rather than going in blind, I'm pausing in the hope of get an idea of how both ends come apart, it's in better shape than I thought and don't want to make things worse.
Thanks in advance.


I wish I had bought those three so I could take a look (when I spot them, there were just listed).

Hopefully you can sort the things out smoothly!


PostPosted: Wed Jul 29, 2020 5:11 pm    Post subject: Reply with quote

Lightshow wrote:
tomasg wrote:
Unfortunately i have no experience with those variants of the Topcors, but i wanted to say kudos to you, an experienced lens tinkerer stopping and asking for help.

Tomas

I feel like a doctor, do no harm...

"Experienced lens tinkerer" Thanks. 😊


I hope there s nothing bad in that frase, if yes i apologize, English is not my first language. I based that comment on the many posts from you that i see here and on DPReview.


PostPosted: Wed Jul 29, 2020 5:16 pm    Post subject: Reply with quote

Make a tool using pvc pipe & some rod stock?


PostPosted: Wed Jul 29, 2020 7:28 pm    Post subject: Reply with quote

The Nikkor-SC 5cm F2 in Leica Thread Mount requires a tool similar to this to remove the rear group.

I cut up an old Tripod Tubular Leg (broken), the folding legs gave different sizes. One of them worked.

Look around the house, or in the hardware shop.


PostPosted: Sat Aug 01, 2020 1:33 am    Post subject: Reply with quote

tomasg wrote:
Lightshow wrote:
tomasg wrote:
Unfortunately i have no experience with those variants of the Topcors, but i wanted to say kudos to you, an experienced lens tinkerer stopping and asking for help.

Tomas

I feel like a doctor, do no harm...

"Experienced lens tinkerer" Thanks. 😊


I hope there s nothing bad in that frase, if yes i apologize, English is not my first language. I based that comment on the many posts from you that i see here and on DPReview.

No, nothing bad, was actually an accurate description IMO.


PostPosted: Sun Aug 02, 2020 3:43 pm    Post subject: Reply with quote

Like 1 small


PostPosted: Mon Aug 10, 2020 11:35 am    Post subject: Reply with quote

The RE Auto-Topcors up to 100mm focal length are all similar. The focusing helical is all aluminum. The aperture mechanism is in the form of a cup, with the bottom near the rear of the lens. It is made of black anodized aluminum. The front and rear optical blocks are connected to the aperture mechanism. The rear optical block screws into the aperture mechanism. The front optical block is held by a retaining ring.

The aperture mechanism and the two optical blocks are held into the focusing helical by an outer retaining ring. You want to remove the rear lens mount before you pull the aperture and optical block. That's because it has a fork and rod that engage with the aperture mechanism. You also want to remove the filter ring first, and perhaps the front sleeve, to get better access to that retaining ring.

If you have to disassemble the aperture mechanism to clean the leaves, make a scribe mark on the front ring and side of barrel, as the exact rotation of that front ring calibrates the aperture. It's held by three set-screws.

Infinity focus is collimated by a selected (and possibly hand-filed) spacing ring between the aperture mechanism and the focusing mount.


PostPosted: Mon Aug 10, 2020 5:15 pm    Post subject: Reply with quote

My request has nothing to do with the RE series, thanks anyways for the effort.