Digitising Historical glass lantern slide photos

In the first instance I scanned some of the slides using a flat-bed scanner (Canon Canoscan 8400F). However, I felt I could do better - the scanner's software was never intended to cope with a 3¼ x 3¼ glass lantern slide, so it cut off the top or side of the picture. Quality was good, but I thought it could be improved.

So I decided to re-photograph the pictures with a Canon EOS 350D, using the standard lens (EF-S 18-55mm f/3.5 - 5.6 USM). This standard lens has a minimum focal length of 28cm - at which a 3¼ square inch glass plate slide nicely fits the screen.

I made a slide holder and adjustment device to mount with the camera on a tripod, with a cowl. In principle this is similar to the old bellows type slide copiers one used to be able to get in the days of film SLR photography. Behind the light is a translucent acrylic diffuser. I also manufactured a plain slide from a piece of transparent plastic, with cross hairs scratched on it, to centralise the slide in the lens and make sure the camera and slide are properly aligned.

I also made a remote shutter release switch, using information found on the www. This uses a push-button switch which is actually an operator button working two separate microswitches. As originally purchased the two microswitches operate simultaneously but it was very easy to insert and fix in place a shim so that one microswitch makes before the other, giving the same shutter release with pre-operated focusing, as does the camera's own release.

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Page first published 23rd December 2008
Last modified: Wed, 29 Nov 2017 09:10:26 GMT
Page written by Richard Torrens
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