Back/Rear standard on Topcon Horseman 970 - Advice Wanted

[ags2mikon]

Most of the ones I'v seen on evilbay didn't have the adapter ring. Anybody have a suggestion to make the adapter?

 

[Dan Fromm]

I didn't realize it works on other lenses too. Thank for posting

Pardon the late reply. The Horseman TC will work -- I don't know how well -- with any lens in #0 shutter whose rear cell will fit inside the front of the TC.

 

[Dan Fromm]

Most of the ones I'v seen on evilbay didn't have the adapter ring. Anybody have a suggestion to make the adapter?

The adapter is a much modified retaining ring for a #0 shutter. The hole at the front is threaded M32x0.5 to screw onto the rear of a #0. The adapter has a centering ring, just like a proper retaining ring. There's a cup-shaped section behind the front that is ~ 11.5 mm deep and threaded to accept the front of the TC. If you're not up to making one, Skgrimes can do it. I've been dithering for years about whether to ask Grimes to make an adapter for mine with a retaining ring for a #1, haven't asked them for a quotation. There are other machine shops.

Alternative 1, probably less expensive: wait for a complete one to turn up on ebay.com

Alternative 2, probably less expensive: wait for a complete one to turn up on yahoo.jp. I get into yahoo.jp's auctions via https://buyee.jp/yahoo/auction?lang=en Many of the ones I've seen on yahoo.jp don't have the adapter ring.

Alternative 3, ask BS Kumar, who is in Japan and posts here, to find a complete one for you.

 

[ags2mikon]

Thank you Dan. You are a great source of good information. Do you know what the thread size on the TC itself is? I may e-mail RAF camera and see if he can make one.

 

[ic-racer]

Just re-reading this old thread. I did just realize that the converters and adapters shown in post #24 and #20 are actually different!

This would make finding an isolated adapter ring of the correct type even harder and speaks more to having SK Grimes or RafCamera fashion an adapter to an existing teleconverter.

 

[Dan Fromm]

Just re-reading this old thread. I did just realize that the converters and adapters shown in post #24 and #20 are actually different!

This would make finding an isolated adapter ring of the correct type even harder and speaks more to having SK Grimes or RafCamera fashion an adapter to an existing teleconverter.

Are you sure? I ask because the apparent intermediate adapter ring shown in the drawing in #24 isn't part of the TC shown in the same post. It is the lens' rear cell. What the drawing in #24 labels TC is the TC plus the rear adapter ring. Both posts show the retaining ring/front adapter, rear adapter and TC.

Side comment, I've been watching these things for ages on eBay and on yahoo.jp. All the ones I've seen have been the same. As always, I could be mistaken.

If ags2mikon has only the TC (short tube with lenses in it) he's probably cooked. I suspect that the dimensions of the rear adapter ring are slightly critical.

 

[ic-racer]

Are you sure? I ask because the intermediate adapter ring shown in the drawing in #24 doesn't seem to be part of the TC shown in the same post. What the drawing in #24 labels TC is the TC plus the rear adapter ring. Both posts show the retaining ring/front adapter, rear adapter and TC. The intermediate adapter shown in #24 is a mystery.

Side comment, I've been watching these things for ages on eBay and on yahoo.jp. All the ones I've seen have been the same. As always, I could be mistaken.

What do they look like? You see, mine (post #20) has a deeper adapter ring and a shorter flange on the adapter, compared to the picture in the catalog.
If I were to screw my teleconverter to the adapter ring in the catalog, the optics would hit.

 

[Dan Fromm]

Thanks for explaining. Now I see what you mean. Mine's rear adapter is ~ 22 mm deep. How deep is yours?

There's a better picture of the device at https://www.cameraeccentric.com/static/img/pdfs/horseman_2.pdf p. 37 that shows a front adapter that seems to be shorter than mine and a rear one that appears to be longer. The one in the catalog could have a longer total length than mine but I'm not sure. What do you think?

 

[ic-racer]

I just checked ebay and also your web page and it looks like the picture in the catalog might be a prototype, none of them look like the one in the catalog.

 

[ags2mikon]

@ic-racer that was my thought too. Marketing and engineering didn't communicate well enough. So its 22mm deep, but what is the thread?