From Compur 5FS to Compound V ?

[Marco Annaratone]

I have a lens mounted on a Compur Electronic 5FS and I am considering buying a Compound V to mount the lens on it. Neither shutter is very popular, but the little info I found seems to indicate that they have the same internal diameter (+/- 0.5mm?).

Has anybody out there ever moved a lens mounted on a Compur electronic 5FS to a Compound V? I’d love to hear re: feasibility.

Thanks!

Cheers

Marco

[Dan Fromm]

Marco, tube length matters too. For Compound shutters' tubes' inner diameters and lengths see: http://www.largeformatphotography.info/forum/showthread.php?23904-Compound-shutter-sizes. I don't know whether Ole's list is exhaustive. I don't have a source for the Compur 45FS's tube length but since you have one you can measure. Measure and tell us in another thread "Compur 5FS shutter's tube length."

Re feasibility, I've had discussions with Adam Dau at SKGrimes about remounting cells from one shutter into another whose tube's inner diameter was a little larger than the first's. They that the insert required was impossible because of wall thickness problems, too thin.

[Marco Annaratone]

Ok, I did my homework and failed.

Is there anybody out there who owns an Apo-Lanthar 300/4.5 mounted on a Compound V shutter who can take a couple of measures for me pleeeeease?

The Apo-Lanthar was mounted on a Compur 5FS with a tube length of 60mm. So I jumped on a Compound V on sale with that tube length. It is a Type II, and in fact its mount depth corresponds to Ole's table (25.2mm).

The problem is that with that mount depth and tube length the front cell of the Apo-Lanthar cannot be screwed into the shutter without touching the blades.

Was the Apo-Lanthar 300/4.5 actually mounted on a Compound V that was neither Type I (74mm, wrong tube length) nor Type II (25.2mm mount depth leaves not enough depth in front), perhaps?

Hence my question: anybody out there with an Apo-Lanthar 300/4.5 on a Compound V who can measure the tube length *and* the mount depth?

TNX!!

[pjd]

You could find some photos of the lens in question and make some measurements on screen, then extrapolate from known dimensions to get to an estimation of tube length.

[Marco Annaratone]

You could find some photos of the lens in question and make some measurements on screen, then extrapolate from known dimensions to get to an estimation of tube length.
Thanks, that’s what I had done already but the numbers from three different lenses seem to be quite different, a +/- 5% that does not help if one wants to buy a Compound V without trying it out first or needs some metal work to adapt one. Anyway, tube length tends to be between 52mm and 56mm, quite far from 60mm. (On my 5FS it turns out be 58mm, certainly closer to 60mm but *definitely* not 60mm).

At this point I am 99% convinced that the Apo-Lanthar 300/4.5 requires its very own Compound V (I am referring to the E and F quotes in Ole’s original thread, the others are fine). There is only one “unless”, but I frankly find it hard to believe on optical grounds. Unless, that is, the Apo-Lanthar 300/4.5 was specifically produced in a version for the Compur 5FS, with measures different from those of the Lanthar-for-the-Compound_V.

Anyway, The only indisputable fact :D is that my know-how of Apo-Lanthars 300mm is a sample of one mounted on a Compur 5FS. Go figure.....

Cheers!