Talk:Johann Coaz

Photo query
I've copied the below from the reference desk, where I posed a question about the veracity of one of the images used in this article.

Camera on a timer in 1850?
I'm writing an article on Johann Coaz and am a little suspicious of a photo I've put in the article. This photo (right) purports to show Coaz and two others on the first ascent of Piz Bernina (according to its description in the Commons). Given that there was no one else around, could this photo have been taken on a timer with the technology available at the time (I'm hoping it could have been), or is it a shot from a different ascent that has been mislabelled? The rockiness of the summit could certainly be Piz Bernina. The source (naturfreunde-maiengruen.ch) is not very helpful at all... Ericoides (talk) 16:02, 18 July 2012 (UTC)
 * Here's a little history of the camera shutter for some background. This suggests that in 1850 the photographer would not have been using a shutter as we would recognise it, so also wouldn't be able to use a release timer. It seems that they would have come in about 1880. Having said that, I think that if the camera did have a shutter, the technology existed (Clockwork) to enable a delayed shutter release. However, looking at camera technology, this page tells us that Wet plate photography didn't come in until 1851. This photo (if it was taken in 1850) must, therefore, be a Daguerreotype. Here you can see the process involved in taking such a photo, with exposure times from 10 seconds to 30 minutes(!). A reasonably long exposure (maybe over 30 seconds or so) might be enough for the photographer to quickly skip round in front of the camera and arrange himself in an 'I've been here all along' pose. What do you think? - Cucumber Mike (talk) 16:15, 18 July 2012 (UTC)
 * An ingenious reply, thanks, but would there not be a trace of his movement on the image? Ericoides (talk) 16:31, 18 July 2012 (UTC)
 * At low sensibility film, there wouldn't be any traces. The sensitive material just register up a certain threshold. If the exposure time is several minutes, then things in the ball park of some seconds won't show up. Apparently, it was not unusual for photographers in the XIX century to portrait themselves: []. OsmanRF34 (talk) 16:36, 18 July 2012 (UTC)
 * OK, that sounds sensible, thanks. Two further questions: which one is Coaz, and which one took the photo? My hunch is that Coaz is on the right, looking at the camera, and the fleet-footed photographer is the man standing on the left (who might well also be Coaz). Ericoides (talk) 17:19, 18 July 2012 (UTC)
 * Looking more closely at the photo, the standing man and the man sitting on our left are holding things that look a little like posing stands. Could it be, therefore, that the man sitting on the right looking directly at the camera is the photographer? Also, you labelled the photo 'Coaz and the Tscharner brothers'; the two men who look most like brothers are the one standing and the one on the right (the potential photographer) - they seem to have similar facial features. If I've got that right, my bet for Coaz would be the man sitting on the left. Admittedly, I'm getting into rather serious guessing now! - Cucumber Mike (talk) 21:37, 18 July 2012 (UTC)
 * They are holding alpenstocks, the rather long version of the modern ice axe. Ericoides (talk) 05:51, 19 July 2012 (UTC)

Also we seem to be looking down on the summit. When was the helicopter invented? ;-) Alansplodge (talk) 22:16, 18 July 2012 (UTC)
 * It's an optical illusion. The camera is probably on a standard 5-foot-tall tripod, sitting on a nearly-level ridgeline, aimed slightly downward. --Carnildo (talk) 22:47, 18 July 2012 (UTC)
 * I have taken pinhole camera photos of myself and others, with exposures of over a minute, and it was quite possible to start the exposure, run to my place in the photo, then run back and stop the exposure. I would not care to run across the ice and rocks evident in the photo. How sure are you there was no 4th person present? If I carried a view camera on a tripod up a mountain, I would not think it much of an additional burden to also bring a remotely operated shutter, even though in those days exposure control was usually by removing the lenscap, counting or timing the exposure with a watch, then replacing the lenscap. A "Bulb" shutter exposure was done by squeezing a rubber bulb attached to a long, thin rubber hose, with a shutter which opened when the bulb was squeezed and closed when it was released. Such bulb-hose-shutter arrangements were in use by 1853: "The Photographic journal: Volume 83, books.google.com Royal Photographic Society of Great Britain, Photographic Society of London - 1853 - Snippet view: "The camera ran on castors, and its height was adjusted by attachment to a pair of tall steel rods, up and down which it slid, and could be fixed at any desired position. Fxposure was made by means of a rubber tube and bulb. The shutter ..."

The adding of a remotely operated shutter would have been a pretty obvious alternative to running back and forth on a slippery mountaintop. The photo as presented is too low res to look for evidence of a remote operated shutter. Photos by 1850 were made on paper negatives, and not just Daguerrotypes. Edison (talk) 19:51, 19 July 2012 (UTC)
 * I think we can be certain that if this is a photo of 13 September 1850 then no one else was present. All records of Piz Bernina's first ascent say it was by Coaz and the two Tscharner brothers. On such a prestigious first ascent we'd definitely know if there was a fourth person in the party. Ericoides (talk) 07:37, 20 July 2012 (UTC)


 * I think that the strange quality of the light on the rocks and the completely indistinct background of the sky point toward a very long exposure. Wnt (talk) 11:08, 20 July 2012 (UTC)

External links modified
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