AERIAL CAMERA TYPES K-17, K-18, K-19B, AND K-22
The 20th did nearly all its aerial photography with two camera types: the K-17 and K-18. The K-17 was a 9" x 9" format (negative size) mapping and reconnaissance camera. It had three major components: a body, containing most of the mechanics and controls; a detachable magazine for 9 1/2" wide roll film; and a lens cone, with 6", 12", or 24" focal length options. The K-17, like the other three cameras in this section, was developed and built by the Fairchild Camera and Instrument Company.
The K-18 reconnaissance camera differed markedly from the K-17 in construction. The K-18 body and lens cone were built as a single unit housing a 24" focal length lens. Film format was 9" x 18".
A handful of night photography missions were flown with K-19B cameras in June and July 1945. The K-19B had a 12" lens, was of 9" x 9" format, and had a shutter that was operated by an attached photocell unit. The K-17, K-18, and K-19B all employed between-the-lens shutters.
The squadron was provided an abundance of K-22 cameras, but never used them for a combat mission, having found them "...unsuitable for mapping and not entirely satisfactory for reconnaissance..." (Interestingly, the F-7A's and B's were designed for a pair of K-22's to be mounted at the camera bay split vertical station.) The K-22 was a 9" x 9" format camera with lens cone options of 6", 12", 24", and 40" focal length. Unlike the others, its shutter was a focal plane type.
All these cameras were normally operated from a 24 VDC electrical source, but could be manually operated by a hand crank and shutter lever (the K-22 was electrical only). Each was fitted with a connector for an intervalometer that fired the camera at an interval set by the aerial photographer.
All used a vacuum applied to the film magazine to flatten the film surface before each exposure.
While these cameras were normally clamped into mounts, a pair of handles and a viewfinder could be fitted to K-17's and K-18's for hand-held operation. What "hand-held" meant is subject to interpretation, as these cameras were not lightweights. With a 200 foot roll of film, the A-5 film magazine used with the K-17 weighed 30 pounds. A complete K-17 with 12" lens cone and a full magazine weighed about 55 pounds. With a 24" lens instead of the 12", the weight climbed to near 75 pounds.
All four of these cameras used 9 1/2" wide Eastman Aerial Safety film. Film emulsions were Class L and Class N. Class L was the "normal" high-speed panchromatic film. Type N was labeled extra high-speed panchromatic, and was used for night photography in the K-19B's. The common lengths of film rolls were 200 feet and 75 feet. (Two hundred feet was the maximum film load for an A-5 or A-5A magazine. The A-7 magazines used with K-18 cameras held a maximum of 75 feet.)
K-17 Reconnaissance and Mapping Camera Data
The K-17 was the most common--and versatile--of the Army Air Force aerial cameras. With the 6" focal length Metrogon lens, it was the standard mapping (also called charting, or cartographic) camera of its day--and its day extended to long after the war. This was the combination used by the 20th in its trimetrogon setups.
The 20th did some reconnaissance photography with the K-17 and 12" lens late in the war, but for the most part the K-17's were used for mapping with the 6" Metrogon lens. (The combination of a 6" lens and 9" x 9" negative remains the mapping standard in the U.S. to this day.)
__________________________________________________________ Format: 9" x 9" Lenses: 6" f.l. - f/6.3 - 73.74° x 73.74° view angle 12" f.l. - f/5.0 - 41.11° x 41.11° view angle 24" f.l. - f/6.0 - 21.24° x 21.24° view angle Shutter: Between the lens 6" - 1/50, 1/100, 1/200, 1/300 second 12" - 1/75, 1/150, 1/225 second 24" - 1/50, 1/100, 1/150 second Control: Manual or intervalometer Cycle time: 3 seconds, frame-to-frame Magazine: A-5 or A-5A - 200 feet - 250 exposures ___________________________________________________________
K-18 Medium to High Altitude Reconnaissance Camera Data
The K-18 was one of the two workhorses of the 20th CMS--and of the Army Air Forces in general. (The other was the K-17.)
The 20th generally installed two K-18's in the camera bay; one each at the vertical and split vertical stations. Orientation was with the 18" image dimension transverse to the flight path.
___________________________________________________________ Format: 9" x 18" Lens: 24" f.l. - f/6.0 - 21.24° x 41.11° view angle Shutter: Between the lens 1/50, 1/100, 1/150 second Control: Manual or intervalometer Cycle time: 8 seconds, frame-to-frame K-18A (late-war): 3 seconds, frame-to-frame Magazine: A-7 - 75 feet - 45 exposures A-8 - 390 feet - 245 exposures ___________________________________________________________
K-19B Night Reconnaissance Camera Data
A few night photography missions were successfully flown using the K-19B in 1945. The June 1945 Squadron History report cites success at 12,000 feet with the flash bombs (used to illuminate ground targets) set for 3,000 feet. Shutter speed was 1/50 second. The shutter in K-19's was triggered by a photocell which detected the flash bomb ignition.
___________________________________________________________ Format: 9" x 9" Lens: 12" f.l. - f/2.5 - 41.11° x 41.11° view angle Shutter: Between the lens 1/25, 1/50, 1/100 second Control: Light-activated via photocell Cycle time: 3 seconds, frame-to-frame Magazine: A-5 or A-5A - 200 feet - 250 exposures ___________________________________________________________
K-22 Reconnaissance and Charting Camera Data
The K-22 with 24" lens cones were the cameras delivered in the split vertical mounts of all F-7A's and B's the 20th received new--but the squadron never used them for a combat mission.
___________________________________________________________ Format: 9" x 9" Lens: 6" f.l. - f/6.3 - 73.74° x 73.74° view angle 12" f.l. - f/5.0 - 41.11° x 41.11° view angle 24" f.l. - f/6.5 - 21.24° x 21.24° view angle 40" f.l. - f/5.0 - 12.84° x 12.84° view angle 40" f.l. - f/5.6 - 12.84° x 12.84° view angle 40" f.l. - f/8.0 - 12.84° x 12.84° view angle Shutter: Focal plane A curtain: 1/135, 1/300 second B curtain: 1/400, 1/800 second Control: Manual or intervalometer Cycle time: 3 seconds, frame-to-frame Magazine: A-5 or A-5A - 200 feet - 250 exposures ___________________________________________________________
OTHER FAIRCHILD AERIAL CAMERAS: K-20 and F-56
There is no mention of the K-20 being used in any of the 20th's monthly reports, but they were probably carried and occasionally used for hand-held oblique shots.
___________________________________________________________ Format: 4" x 5" Lens: 6.375" f.l. - f/4.5 - 34.84° x 42.83° angle of view Shutter: Between the lens 1/125, 1/250, 1/500 second Control: Manual Magazine: Part of camera, 20 feet - 50 exposures ___________________________________________________________
F-56 Reconnaissance Camera Data
The Navy's F-56 series was not generally used by the Army Air Forces, but is included here to round out the stable of large aerial frame cameras that Fairchild built during WW II.
___________________________________________________________ Format: 6 5/8" x 7" (roll film) Lens: 5.25" f.l. - f/6.3 - 64.50° x 67.38° view angle 8.25" f.l. - f/4.0 - 43.75° x 45.98° view angle 20" f.l. - f/5.0 - 18.81° x 19.85° view angle 40" f.l. - f/8.0 - 9.47° x 10.00° view angle Shutter: Between the lens 1/35, 1/50, 1/100, 1/150 second Control: Manual or intervalometer Magazine: A-1A - 120 feet - 200 exposures ___________________________________________________________
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This page was last updated August 2, 2010