CAMERA MARVELS

Wairarapa Times-Age, 14 April 1941, Page 7

CAMERA MARVELS

EVES OF THE ROYAL AIR FORCE PICTURES FROM 20,000 FEET. IMPORTANCE IN PRESENT WAR. Because of the longer range and greater accuracy of ground guns aerial photography in this war has been more difficult than in the last, despite the progress made in the equipment and methods states an aviation correspondent of “The Times.” In the last war a reconnaissance machine was reasonably safe at 8000 ft. to 10.000 ft.. and from that altitude good photographs could be obtained. Now. unless it is to risk being shot down, an aircraft engaged on this work over strongly defended areas must operate at 20.000 ft. or more.

Such an altitude brought obvious handicaps. Pictures taken from a great height naturally decrease the scale and the detail of the objects on the ground. To “bring up” those details long-lens cameras were employed, but these in turn had their drawback, for they called for more accuracy of aim and increased the risk of missing the mark. Bigger cameras were necessary, more than one in an aircraft, and they were not easy to instal. Even worse was the freezing of cameras: there were frequent mechanical failures; and condensation formed cn the lenses. Cameras were also affected by vibration and high speed. TELL-TALE PICTURES.

That all these troubles have been tackled and overcome is clear from the pictures obtained. For a variety of reasons it is not always possible to publish photographs taken over enemy territory, but those of Taranto harbour, taken after the Fleet Air Arm's raid cn Italian naval units, those of the first raid on Kiel. as well as others of Hamburg. Stettin. Berlin, and elsewhere, have given the lie to the inevitable enemy claims that no damage was done.

Photographs are not only used to show Hie consequences of bombing raids; frequently they lead up to them. Much of the information about enemy activities, such as ship and troop movements, is gained from photographic reconnaissance flights. As soon as pictures indicate the existence of an important’ target the R.A.F. Bomber Command get busy, and afterwards the scone of the operations is. often photographed again to make sure that -the raid was successful.

THE NIGHT LENS. ! Air photographs can be taken at I night, though searchlights, bursting 'shells, and incendiary bullets can and :do sometimes defeat the camera. If I the weather is good and the ground i defences not too active, the R.A.F. can I guarantee a “readable" night photoI graph taken from as high as 4000 ft. Lenses used for night photography : have a much wider aperture than lenj scs used in daylight. Flash bombs are I employed to illuminate the objects on ■ the ground, and the flash automatically I closes the camera shutter by means of' I a photo-electric cell. . ! After careful examination of enemy I cameras and the pictures taken by I them, our experts are convinced that. I generally speaking, we are ahead of Germany and our lenses superior. The | laboratories, the advice, and the ex- i periments cf the two largest photo-! graphic firms in the country are con- • stantly at the disposal of the R.A.F.. so (hat not only in cameras and films, I but hi processing methods, improve-,’ ments are always being made. Faster; and better films permit of wide mar- ' gins cf error in exposure, either "over" I or "unde’.'." and yet give “readable" i photographs. The laboratories have I contributed cihulsions for films of in-1 creasing speed and finer grain, pan- • chromatic coatings that make for | greater sensitiveness to the red end of I the spectrum, infra-red films, and al bromide emulsion which provides for j either contrasting or soft, effects in I printing.

ELECTRICAL OPERATION. The aerial camera is now a “precision instrument," simple to handle, and standing up to hard wear and tear. When employed in taking vertical photographs it is electrically operated and starts at the turn of a timing switch. The control unit continues to make exposures at sot intervals. either until it is switched off or the film runs out. If a few exposures are enough, only a control button need be pressed at the time intervals required, After the release of the shut-