View Full Version : lens assembly from pieces

gary ness
18-Sep-2005, 03:16
A recent sale offered front and rear "elements" for a Schneider G-Claron 270mm lens, stating that they would fit a Copal # 1 shutter. Sometimes these offfers seem to be good deals but it is not entirely clear what is needed to get the lens assembled and ready to use. I am specifically interested in using the lens on my Deardorff 8x10 and I have asked sellers these types of questions but they do not seem certain about all the details. What is clear is that the front and rear elements must be able to screw onto the shutter and a suitable lens board and mounting ring are necessary. But is there more to be thinking about? Are there other pieces needed that are not obvious? Are there assembly variations to think about before jumping into one of these "kit" assembly purchases ? What other problems might one encounter? Thanks. Gary

tor kviljo
18-Sep-2005, 03:49
Schneider G - Claron 270 lens will fit directly into a Copal size 1 shutter, and the spacing is supposed to be the same as that of the original barrel (i.e. aperture mechanism) most of these lenses were supplyed in (for use on vertical repro-cameras of the pre-mac-age). However, in order to make the lens work on Your Deardorff, You need a copal or modern prontor/compur shutter (all of these have identical thread-sizes in nr. 1 shutter, but older compurs (& possibly Prontors as well?) are different! They have different threads & can not be refitted with modern lens-cells!!!) + You need info. to calibrate apertur scale as it's unlikely that the shutter You find (used, I guess, a new one will hardly pay) have scale for this lens/FL. You make your own aperture scale easily if You have the original barrel-mount and can trace (using vernier caliper with care!) the aperture opening of the barrel-mount -aperture at different stop & transfere the setting to the shutter & home-made apertur scale You will use. Quite easy, and every other stop (f 4, 8, 16 , 32) is exactly half diametre of previous in the row, so you have help along the way getting it right.

If the aperture scale on the shutter you buy is entirely linear: i.e. the physical distance (= the distance the pointer moves along shutter-rim) between f 8, 11, 16, 22, 32 on the scale is identical, then You just need to adjust the position of the scale so that the aperture of the shutter have the correct diametre for f 11 when set at f11. the other stops will then be correct.

The G-Clarons is excellent & very sharp semi-wide lenses when stopped down, but they are relatively cheap also when new, so i would not use too much money & hassle to make it work - there is too much readily available & good LF lenses around to justify time or money on roothless lens cells.....

Now, if on the other hand, You had a Sinar Copal shutter, then You could take any barrel lens & mount on suitable board - having access to loads of good cheap & not-necessary-to-remount repro & enlarger lenses at about the cost of the shutter alone... I have used my DB shutters for years - using it with diverse lenses at small cost, and a used Sinar-Copal shutter is about the price of a new copal 3 I guess. But You need a sinar/Horseman/Inka or a quick refit to other monorail with at least 140x140 boards to use it - the rest is just joy.

Good luck anyway!

gary ness
18-Sep-2005, 05:46

Your comments are most useful. it seems most reasonable to adopt your recommendation to buy the relatively inexpensive intact lens-shutter combination rather than hoping to calibrate the aperture settings on pieces that may or my not work together. Many thanks for your fast and most informative reply.


Kevin Crisp
18-Sep-2005, 07:49
Gary: I have a number of G Clarons and most were puchased very reasonably as lenses in barrel and installed in a shutter by just screwing them into a No. 1 copal or an older No. 1 Compur such as used on the Schneider convertible lenses. (Or a Copal O, in the case of the 150 GC.) The measurements of spacing have come out perfectly with no shims necessary on every one I've done. Making a scale for your new lens/shutter combination is quite simple, with no math involved, when your barrel lens comes with a barrel with iris, as most of them do. You just set the size of the aperture the same and copy it over. The SK Grimes people can do a nice factory-appearance scale for you, as an alternative, for around $45, which will look less do-it-yourself. By all means, if you have the money and want to spend it, obtain an original factory lens in shutter. The savings of putting together a shutter (especially a used one taken off some other very inexpensive combination, such as a convertible schneider with separation) and a barrel lens can be significant. Make sure you don't get the wide angle claron, which is a different animal.