WSJ Documentary - US spy planes continue to use wet-plate photography
Join Date: Feb 2017
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I'm not sure why the OBC has never been digitized, while frame cameras like the UTAS DB/MS-110 and MS-177 series have been. It could be that the OBC has long been considered to be on the brink of retirement.
However, it is not unique simply because it still uses wet film. The continuous rotational scan covers a 40-mile-wide strip from the Firefly's operating altitude (72000-78000 feet) and it carries enough film to make the strip 1700 miles long. Resolution on-track was one foot, declining towards the edges of the track because of distance. I believe that the goal was to gather information on Chinese targets in regions where there were no good maps.
However, it is not unique simply because it still uses wet film. The continuous rotational scan covers a 40-mile-wide strip from the Firefly's operating altitude (72000-78000 feet) and it carries enough film to make the strip 1700 miles long. Resolution on-track was one foot, declining towards the edges of the track because of distance. I believe that the goal was to gather information on Chinese targets in regions where there were no good maps.
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Don't know about the camera on the U2 and Canberra, but as a bit of a photography enthusiast I have great fun when I went on the Tornado camera pod course back in the late 90's. The pod housed two cameras manufactured by a UK company, and they were real pieces of mechanical engineering which had taken the technology of photographic film cameras to the limit. With a stable platform being flown at a set speed the clarity of the images was amazing, and the level of detail you could see from a considerable distance was like something out of science fiction.
The bonus of using the film method rather than optical sensors as we do in digital cameras was that once the film had been exposed and developed, you could go back to it over and over again using different developing techniques to get slightly different images. Plus you could use good old fashioned glass magnifying optics to select specific areas, once a digital sensor has been exposed to the image the only way you can magnify the image beyond the resolution of the sensor is to digitally "guess" what the gaps between the pixels look like.
The bonus of using the film method rather than optical sensors as we do in digital cameras was that once the film had been exposed and developed, you could go back to it over and over again using different developing techniques to get slightly different images. Plus you could use good old fashioned glass magnifying optics to select specific areas, once a digital sensor has been exposed to the image the only way you can magnify the image beyond the resolution of the sensor is to digitally "guess" what the gaps between the pixels look like.
