Thursday, February 23, 2012

ELCAN (ERNST LEITZ CANADA) UNDER WATER SYSTEM

The following is part of a documentary about ELCAN - Ernst Leitz Canada

Besides the manufacture of cameras and lenses, ELCAN was also very much involved in the manufacture of military equipment.  One of the most unusual military developments was an underwater camera system which Leitz developed for the US Navy.  It primarily consisted of a complete set of lenses for underwater work, not only for 35mm cameras but also for medium format, 16mm motion picture and TV cameras.  These were rather unique lenses because they were not part of a camera that was simply put into a water tight housing.  Instead the lenses were designed to be exposed to the water with their front element.  The usual way of using under water housings for conventional cameras usually incorporate standard lenses that are designed to work in air.  For thoseLeitz/Leica even takes the refractive index of air into consideration when designing their lenses.


     35mm System

    Motion Picture or Video system


    Three Lenses with the common Water contact Front Element

The Leitz under water system instead was designed according to the refractive index of water.  As a matter of fact, since this system was to be used primarily in salt water, it was the refractive index of salt water that was used in the design of these lenses.  However, not all oceans have the same salinity.  So Leitz went one step further and took the refractive index of the salinity of the various oceans into consideration.  This was possible with an interchangeable front element of their water contact lenses.  This overall design actually considered the water as an integral lens element of the entire system.   To avoid the need to test these lenses in the various oceans all over the world, Leitz built a large water tank that could be flooded with water of the appropriate salinity.

The correction of these lenses was so good that, when water is clear enough, there is no way of telling that the pictures were taken under water.  Leitz was the first company to suggest such a design. 
What is even more amazing is the fact that the thick water contact front element is so strong that the lenses can be used in the greatest ocean depths without any problems at all, including the deepest part on earth, the 36,200 feet deep Challenger Deep of the Mariana Trench.

2 comments:

  1. The complete ELCAN article will be published at a later date.

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  2. The Leica and cameras and photography in general certainly offer a lot of topics for discussion. But we must not forget the ultimate purpose of why we have cameras; to take pictures. For that reason I would like to start a weekly (or possibly daily) gallery of photographs. But I don’t want this to be a showcase for just my own work; to the contrary, I would like to encourage everyone to submit photographs for display on this blog. The copyright to the photographs will remain with the photographer and no pictures will ever be used for any other purpose unless permission is given by the copyright holder.
    No registration for this site is necessary. Just email any of the photographs to either of my email addresses at:

    info@gmpphoto.com or gmpphotography@msn.com

    If possible, please include the make and model of the camera (any camera, not just Leica) and any other information you deem important.

    It is my hope that this may become one of the most sought after topics of this blog.

    Thank you,

    Heinz Richter

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