Shutter swapping of two 210/5.6 lenses

[Dirk Rösler]

Hello -- I have a Fujinon 5.6/210 and a Nikkor 5.6/210. The Fuji is in a Copal Press #1, the Nikkor in a standard modern Copal #1. Would it be any problem to swap shutters around?

Thanks

Dirk

[Peter K]

Dirk, the threads of the two shutters are the same, so there is no problem. If one of the lens is equipped with a spacer between shutter and lens, the spacer has to go to the other shutter too. Depend on the pupillary magnification factor the mechanical diaphragm size can differ for the two lenses. So the diaphragm scale has to swapped also. If two test-shots taken with both lenses from the same subject with e. g. f/16 shows no difference in density the work is done.

Success,

Peter K

[Struan Gray]

If both lenses are the same type you should be able to use the aperture scales unmodified. A meter reading to 1/10 of a stop may see a difference, but unless you are using the lenses for demanding studio catalogue work it won't cause any harm.

Where you can have problems is if the lenses are very different, for example if one is a tessar and the other a plasmat. Then the magnification of the aperture by the front element my be different enough to make the aperture scales off. The offset would be constant (a given number of stops) so if you don't want to buy or make a new aperture scale you would only need to measure the difference once and remember to apply it in use.

[Dirk Rösler]

Thank you. I cannot see any spacers or shims in either of the lenses. Would they be in front or back, attached to shutter or the element?

Looking at the lens from the front they seem very similar. The front element looks very similar indeed in design, even the filter size is the same, although that may be meaningless. Aperture size seems very close too.

Perhaps I need to take this to some shutter/lens specialist to be certain. I don't want to mess up lens performance by doing this...

[Peter K]

Then there is no spacer the lenses don't need one. So swap the shutters and look at the ground-glass. If the image is sharp, specially at the corners there should be no problem at all. At least you can take some test exposures with the same f-stop.

[Dirk Rösler]

Thanks, I will some test shots on instant film tomorrow with lenses wide open and at f32 or so.