Gundlach-Manhattan Triple Convertable

I came across a Gundlach-Manhattan Triple Rapid Rectilinear Convertable mounted in a working Regino shutter. The lens elements are labelled 12" and 17".

It an f8 lens with the elements combined giving a focal length around 7 1/2" an f18 at 12" and f22 at 17". It is a rather diminutive lens but seems to cover 5x7 with ease. However, while the coverage is there the sharpness drops off dramatically at the edges.

Anyone familar with this lens?

What is the best arrangement of the elements to get the marked focal lengths? With the 17" element I get the same focal length if the element is screwed into the front or the rear, same for the 12" element.

Mike

The basic rule is to use single lens cells behind the aperture. The focal length will be the same, but the corrections are better with the single cell behind the shutter. Besides, that's what the aperture markings will be made for. However the bellows extension needed is much larger with the cell behind the shutter than in front, so there are sometimes good reasons for doing it the "wrong" way.

A 7 1/2" RR lens is not supposed to cover 5x7". It may illuminate 5x7", but as you've noticed the sharpness drops off long before the illumination does.

Ole said:

The basic rule is to use single lens cells behind the aperture. The focal length will be the same, but the corrections are better with the single cell behind the shutter. Besides, that's what the aperture markings will be made for. However the bellows extension needed is much larger with the cell behind the shutter than in front, so there are sometimes good reasons for doing it the "wrong" way.

A 7 1/2" RR lens is not supposed to cover 5x7". It may illuminate 5x7", but as you've noticed the sharpness drops off long before the illumination does.

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Thanks fOle or the info - I hope to be shooting a couple of test shots later today. Just popped the lens on my 8x10 Tachi - it gives a really interesting effect - it illuminates the GG-screen even with an inch of rise. But really gives me a giddy feeling with the center being sharp in focus then this wild loss of sharpness towards the edges; with very interesting bokeh. Might make an interesting portrait lens

Measuring the area that looks sharp before the quick drop-off looks like this lens was for 4x5 or smaller - but a 17" lens on 4x5 is pretty dramatic - I wonder what the original camera was?

Mike

MikeK said:

- I wonder what the original camera was?

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My guess is half-plate.

The "standard lens" for 13x18cm plates (very, very close to 5x7") was a 210mm Aplanat, which correcponds very closely to an 8" Rapid Rectilinear. Even that is cutting it very close, and most photographers preferred a 300mm for 13x18cm (if they could afford one).