TYPE LB and BM
The LB Type was the next and last in this series. The LB Type was a further improvement on the L Type and made its appearance in 1918. In general design it was similar to the L Type however the camera mechanisms had been significantly simplified greatly assisting repair and maintenance. The key alteration was the inclusion of an easily removed self-capping focal plane shutter, which could be readily replaced without disturbing the other parts of the camera mechanism. Different lens mounts allowed the use of lenses of 4”, 6”, 8”, 10”, and 20” focus to be used. The lens mounts were interchangeable and were attached via a bayonet fitting on the lower part of the camera body. Other improvements included an exterior lever for adjusting the shutter slit, and a simple method to convert the changer mechanism from hand to power operation. This camera was still in use well into the 1920s having been re-designated P7.
Type LB Camera being handed to an Observer in a DH4 © IWM (IWM FLM 3582)
Type LB Camera being inspected © IWM (Q 12287)
It was during 1918 that the RAF formally changed their naming convention for aerial cameras. P was used for plate cameras, F for film cameras, and G for gun cameras.
The BM Type introduced in 1918 was the ultimate development of the B Type and included all the refinements of the LB Type. Its development was triggered by the need for higher resolution pictures from aircraft that were now flying higher. This was the largest camera used by the RAF and was made entirely of metal. The focal lengths of the lenses ranged from 7” to 20”. The BM Type was an extremely heavy camera and it was not easy to change the magazines which when loaded with plates were also heavy and awkward to handle. When ready for flight with a 20” lens cone and 3 magazines the camera weighed 82lbs.
BM Type Camera © IWM (HU 86136)