Rolleiflex 6008 - Apo-Symmar 150mm Makro driving me nuts

[John Better]

After a lot of chasing (and paying...) I managed to find an Apo-Symmar 150mm Makro, along with an ET67 extension tube, which according to the macro manual of Rollei, should allow me to focus to infinity:

https://lens-db.com/schneider-kreuznach-makro-apo-symmar-hft-150mm-f46-pq/

 

Surprise surprise, the combo focuses only between 1 and 3 meters...

The extension tube being a fixed thing, and the lens being in good shape, I suppose it's a matter of finding the right extension tubes...but which ones?

 

[q.g._de_bakker]

Using a fixed length extension tube the lens focusses at one distance only. The suggestion to use a bellows or a combination of tubes and a helicoid is a good one.

 

But if that lens requires 67 mm for infinity, and it turns out it doesn't do that given that 67 mm, there's something wrong with the lens.

[John Better]

2 hours ago, q.g._de_bakker said:

Using a fixed length extension tube the lens focusses at one distance only. The suggestion to use a bellows or a combination of tubes and a helicoid is a good one.

 

But if that lens requires 67 mm for infinity, and it turns out it doesn't do that given that 67 mm, there's something wrong with the lens.

What is a helicoid?

[q.g._de_bakker]

1 hour ago, John Better said:

What is a helicoid?

The zoom extension tube they mention in the text you quoted. It allows to change the length of the tube, allowing to bring a range of distances into focus. The thing any 'regular' lens has built-in. A bellows unit does the same, over a wider range, but is more cumbersome in use.

Without that, you will be able to bring only one distance into focus.

[SCL]

A helioid is a tubular holder for the lens which is grooved in a helical fashion so that when one turns the outer part the lens moves forward and backward.

[randy_boren1]

If you Google "focusing helicoid" you will find all kinds of info.

[q.g._de_bakker]

When you add up the lengths the text mentions (34, 9 and 9 mm) you do not get 67.  Too short.

Too short means you focus 'beyond infinity', so that will not work at all. So i don't know how correct the text is at all, i.e. including that mention of 67 mm.

 

But Schneider also mentions the zoom extension tube. I have no idea how long that is.

Edit: i know now: 22 - 68 mm. That would fit the 67 mm mentioned. But a fixed 67 tube would be a better choice, seeing that you can't do anything with that lens on the zoom extension tube in the 22 tot 67 mm range.

Edited October 12, 2022 by q.g._de_bakker