Friday, June 10, 2016

British Photographic Reconnaissance Cameras in WW1 - Part 3

TYPE E and L

The bulkiness of the C Type camera, coupled with photograph distortion issues caused by expansion and contraction of the wooden camera body due to changing atmospheric conditions, led to the development of the metal bodied E Type camera. This camera began to be introduced in the autumn of 1916. Metal construction replaced the earlier wood and tubular lens extensions were available to enable varying focal lengths of between 8 to 101/2 inches to be pre-selected. Full automation of the plate transfer and shutter operations was also achieved. This camera, ready for flight, weighed approximately 31 lbs.

E Type Aerial Camera © IWM

The BEF’s experience on the Somme in 1916 highlighted the need for large quantities of aerial photographs. To meet this demand the RFC started to introduce the first near fully automated camera, the L Type, in early 1917. This camera built by the Williamson Engineering Company was the RFC’s first quantity production camera. The lessons gleaned from the use of the earlier cameras were incorporated and new manufacturing methods, alloy castings, were employed.

L Type Aerial Camera © IWM (MH 33751)

Illustrated above is a Williamson L Type vertical aerial camera installation as fitted for external use on an aircraft. Connected to the camera body is a propeller and flexible drive shaft for automatic operation, and a remote shutter-release attached by a Bowden cable. The camera body was a light aluminium casting, containing the plate changer, gear driving mechanism and the focal plane shutter. To this, a cylindrical metal lens adapter was fitted which, on initial models, contained a lens of 6” focal length (seen above): subsequently lenses from 8” to 10½” became standard. The shutter was the same “Goertz-Anschutz” roller-blind type as that on earlier models, fitted with a sliding saddle to adjust the width of the opening, and an internal lens-cap which was mechanically removed during exposure by the shutter release. The magazines were of the same build and capacity as those on the C and E Types, and were placed in similar ‘donor’ and ‘receiver’ positions on the plate-changing apparatus. The L Type could be mounted in any vertical position, either inside or outside the fuselage, and could be operated manually or automatically. For manual operation the first models were fitted with a plunger release, but because of the camera-movement caused by its operation at the moment of exposure, this was often disabled or removed and a Bowden cable used in preference, as seen on this example. When in automatic use, the power came from a small propeller turned by the air stream and connected to the camera by a flexible drive shaft. The operator depressed the release lever to actually take the photograph, the exposed plate was then changed and the shutter was reset by a pinion drive activated by the propeller every four seconds. The ‘L’ Type weighed 37 lbs.

L Type Aerial Camera on BE2c © IWM (MH 33736)