WSJ Documentary - US spy planes continue to use wet-plate photography
 

From a link seen elsewhere:-
The video is a closer look in general at the U2 rather than just about how it records images, plus the journalist enjoys the (rare?) privilege of a flight. All quite interestingWatch the documentary here.

The original 'wet-plate' film - which was on glass or tin plate - had to be exposed whilst the chemical was still moist. I think this was about 5 - 10 minutes after coating. Are we certain this was wet-plate as opposed to film? If so it must have been a very complicated camera and I would have though unlikely for use in a U2 at high altitude.

Modern use of the term 'wet' meaning film and wet development rather than dry process using digital?

I recently scanned some negatives, 120 years old, that were 2x3. To look at the negative there was little to see. Scanned and digitally enhanced the detail was remarkable.

Yes, the term 'wet-plate' is a misnomer - large format black and white roll film is what is being used and this (of course) requires processing in liquid developers - which is what I do at the kitchen sink with b&w films from my 35mm and 6x6cm cameras :)

Your holiday snaps, eh PN? :p

You can get cameras up to 50MP res over the counter.... You can get expensive Hasselblad that do something fancy with the sensors and produce a 200MP image but as the aircraft is moving this won't be an option.

I have a film scanner on my desk which can spit out 90 MP res and 24 bit colour on a 35mm film. Consumer Medium format scanners are 180 MP res and 24 bit colour.


As much as people love the ease of digital photography large format film digital can't touch even remotely for resolution or quality.

They're probably using an array of cameras with lots of post-processing and a stablizing platform, would be my guess. The goal is probably to track serial numbers :)
A 7200 MP camera with 10 degree opening at 120,000 ft would be about 2.8 feet per pixel. I'm sure they want more than that.
The other factor is the range of data per "pixel". Hmmm, hard to compare film vs. CCD there.
Also there's the whole multiple pass trick too, which is great for satellites but maybe not aircraft.

I recall that the U2 aircraft was designed around the camera. 36"inch wide film 1 mile of it.
Designed by Mr Land.
Surely someone will know better.

Yup, it has 2 huge rolls of film, I seem to recall over 100 Lbs. per roll. The two rolls run in opposite direction to not alter the CG of the aircraft as the film is exposed. The lens is pretty awesome, too!

Jon

Which was the same camera in the Canberra PR9.

I am pretty sure that the instrument in question is the Itek Optical Bar Camera, a remarkable piece of kit that dates to the 1960s.

I think I know what you mean, but to remove doubt, would you care to puncture the sentence?

You really mean punctuate don't you?

The camera! (At the Smithsonian Air & Space Museum)

https://cimg7.ibsrv.net/gimg/www.gmf...58e5b45684.jpg

You mean this then?

Presumably airpig means System III (Hycon HR73B?). I think the photo shows a SYERS/RADEOS camera, which was digital.

Again, it's not any conventional framing camera. It's this dude:

https://history.nasa.gov/afj/simbayc...an-camera.html

NASA used a space-hardened version, but the original was for the TRA Model 154 Firefly stealth reconnaissance UAV.

There's more to photography than just resolution. Contrast, or dynamic range, is also a big issue and from what I hear good old film still has the edge over digital sensors in this regard. You can get a sense of this from looking at what a mobile phone does these days; HDR photographs are a composite of 2, taken with different exposures, and then snaffling the good bits from both to make a HDR image. Ok, so phone camera sensors are pretty rubbish, they're silicon based, not GaAs like any decent CCD that a proper digital imaging system would use. But film still beats a CCD for contrast range.

It underlines how remarkable the human eye is with its ability to see detail in gloomy shadows on a bright sunny day that no digital camera can easily capture.

The other irony is that, by definition, digital scanners are also likely incapable of scanning a film print and capturing the full dynamic range, and flat panel monitors aren't capable of displaying the full dynamic range of the print either (even if the scanner could scan it). So there's likely still the odd occasion where a pair of well tuned Mk 1 eyeballs looking at the film itself will see things that are not apparent any other way.

It seems likely that this is no longer the case. Comparison of digital and film images

The win with these cameras is the huge sensor/negative size. These days, at equal image size, digital wins (as I know from the fact that 4/3 digital images of my Leica and Rolleiflex negatives record all the detail they've got).