Satz-Dagor

[E. von Hoegh]

So my 9 1/2" Dagor, in a very early Compound with the composition iris blades suffered a catastrophic failure of said blades. I decided for now to mount the cells in a shutter that once held one of those Wollensak oscilloscope lenses. (It seemed the least labor intensive way to get shooting)

While I was making the adaptor rings, The Lightbulb went on! I once had a 10 3/4" Dagor, traded it off, and have regretted it ever since. So why not machine an extra ring that will adapt the rear cell of the 9 1/2" to the rear of my 30cm Berlin Dagor? That will give me about 10 3/4".

Schneider did essentially the same with the the post WWII triple convertible Symmars, and I read here that Jim Galli has a similar marriage in a Dagor - type G Claron.

So, I'm a better machinist than optician. Am I missing something here? Any thoughts?

[Mark Woods]

Yes. The lens is the focal length it is no matter what shims you use (or adapter rings). Infinity focus is infinity focus no matter what lens you have. And that is what determines the focal length of the lens at hand.

[E. von Hoegh]

Yes. The lens is the focal length it is no matter what shims you use (or adapter rings). Infinity focus is infinity focus no matter what lens you have. And that is what determines the focal length of the lens at hand.

Please read my post, above.

[Ole Tjugen]

No, you're not missing anything.

If you manage to maintain the correct spacing (the distance from the cell to the aperture is probably the best thing to aim for), it should work.

BUT: Do you know the focal lengths of each cell of both lenses? Taking lenses are very rarely completely symmetrical, despite their names. Maybe you won't end up with a 10 3/4" combo, but more like a 10"?

I'm sure you will find out.

[David A. Goldfarb]

Didn't Goerz actually offer a Dagor casket set in the ser. iii era, or possibly earlier?

[Ole Tjugen]

I haven't found anything about a Dagor casket set, but Zeiss offered their Serie VI Protar as casket sets. That's Zeiss Jena, not licenced makers - for most of them, Serie VI was a f:12.5 wide-field lens. Zeiss Jena's VI was a dagor-type convertible lens.

And so were the first Schneider Symmars, of course...

[Dan Fromm]

Andrew, in the '30s Boyer offered Beryl sets. The Beryl was a dagor type. They recommended using either cell alone as well as the two combined. But you will, as Ole pointed out, have to match cell-to-diaphragm distances (or seat to diaphragm, that's probably easier to measure) in y'r replacement shutter.

[N Dhananjay]

The Dagor consists of two symmetrical sets of triplets. It used to be marketed as a convertible and many famous photographs have been made with single elements of Dagors. So,, theoretically, it certainly seems possible to trat the single cells of Dagors like single cells of Protars and combine them to form different focal lengths. However, a few caveats. The single elements of Protars are corrected for coma (Protars consist of 4 cemented elements), while Dagors are not which makes the Protar's use as a single element typically better. Protars were designed to work as convertibles and casket sets and so I'm sure the corrections were optimized with that in mind. Even with Protars, maintaining the correct distance between the cells is important (less so than with non-symmetrical designs but still important). So while you can combine Protars of different vintages, matched cells are more desirable since distances and corrections were probably optimized accordingly. So, I wouldn't be terribly surprised if the distance between the cells does not turn out to be hyper-critical.

Having said all of that, I would say try it. As someone who was remarkably surprised by the quality of a rapid rectilinear on a big negative, I would suggest that you might be pleasantly surprised by the quality you get with what you are trying.

Cheers, DJ

[Ole Tjugen]

Only the Protar VII's consist of four cemented elements.

Protar VI (convertible) were three elements to a cell, others (non-convertible) were 2+2 or 2+3.

[E. von Hoegh]

Well, it works!! And it seems to work well. I'm using the front cell of the 9 1/2, adapted to the rear of the 30cm.(in place of the rear 30 cm. cell) I've yet to figure out the stops, but what I see on the GG is nice - I think it has as much coverage as the 30cm Dagor. I made the adaptor to allow about 3 mm adjustment of spacing; more results as I get them.