tag:blogger.com,1999:blog-7165825989049414848.post4818774169329846900..comments2023-12-25T23:05:21.414-07:00Comments on Obscure Camera: Mechanical Shutter ExperimentsJoe Vhttp://www.blogger.com/profile/10679530650280030752noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-7165825989049414848.post-69127598560470908992016-04-10T01:19:33.329-06:002016-04-10T01:19:33.329-06:00Joe,
During World War Two the US government had s...Joe,<br /><br />During World War Two the US government had some cameras made that (I believe) were called something like Submarine Cameras or Torpedo Cameras. They had a wide angle lens mounted, used 120 roll film and had an unusual image format something like 2.25" x 5". A newspaper I worked for in Pittsburgh, Pennsylvania back in 1970 owned one.<br /><br />What may interest you was that the camera used a "venetian blind" shutter that was mounted behind the lens. I do not remember if there were different shutter speeds available.<br /><br />I experimented with it a couple times to create some unusual photos. What amazed me was that the shutter was actually light tight until the shutter was pressed. And also that the resulting image was perfectly even. Before I used it I assumed that part of the blinds that did not move would cast a bit of a shadow on the negative, but it did not.<br /><br />Maybe you could find some information on these unusual cameras on the web. Or possibly find one on FleaBay.<br /><br />TerryTerry Thomas... the photographerhttps://www.blogger.com/profile/04809283009419422906noreply@blogger.comtag:blogger.com,1999:blog-7165825989049414848.post-14021590152624947822016-04-10T01:12:25.786-06:002016-04-10T01:12:25.786-06:00Joe,
I was playing with something tonight from a ...Joe,<br /><br />I was playing with something tonight from a Dollar Tree store and it came to me that it might be the perfect pre-made device to use to lock the swing arm: a carabiner.<br /><br />Remove the shock absorber and install a carabiner to trap the swing arm.<br /><br />If the shutter has blocked the lens by the time the swing arm is trapped by the carabiner then there is no need for a shock absorber.<br /><br />Simple yet effective!<br /><br />If you still wanted a shock absorber then set up the carabiner so it can tip back to strike the shock absorber and at the same time it will trap the swing arm in place.<br /><br />Terry Thomas...<br />the photographer<br />Atlanta, Georgia USA<br />TerryThomasPhotos@gmail.comTerry Thomas... the photographerhttps://www.blogger.com/profile/04809283009419422906noreply@blogger.comtag:blogger.com,1999:blog-7165825989049414848.post-19999413589136477212016-04-08T23:51:48.422-06:002016-04-08T23:51:48.422-06:00Joe,
I just watched your YouTube video detailing ...Joe,<br /><br />I just watched your YouTube video detailing the design and construction of the 8x10" camera.<br /><br />Then another thought came to me about that shutter speed that leaves the lens exposed:<br />You are fighting gravity! When the arm hits the shock absorber, gravity is pulling on the weighted end of the arm. So rotate the shutter 180* so after the arm hits the shock absorber, gravity will pull down on the brass weight thereby keeping the shutter closed.<br /><br />Terry Thomas...<br />the photographer<br />Atlanta, Georgia USA<br />TerryThomasPhotos@gmail.comTerry Thomas... the photographerhttps://www.blogger.com/profile/04809283009419422906noreply@blogger.comtag:blogger.com,1999:blog-7165825989049414848.post-80942124733440444972016-04-08T23:32:53.817-06:002016-04-08T23:32:53.817-06:00Joe,
I would like to add another thought to my pr...Joe,<br /><br />I would like to add another thought to my prior note. What about using a pair of rare earth magnets to trap the arm after it hits the shock absorber? Or put one on the shock absorber piston and one on the arm. Then when the arm hits the shock absorber, there won't be any rebound because the magnets will stick together.<br /><br />If you have a Harbor Freight in your area you can buy a set of 10 small rare earth magnets for about US $5.<br /><br />Thanks.<br /><br />Terry Thomas...<br />the photographer<br />Atlanta, Georgia USA<br />TerryThomasPhotos@gmail.comTerry Thomas... the photographerhttps://www.blogger.com/profile/04809283009419422906noreply@blogger.comtag:blogger.com,1999:blog-7165825989049414848.post-58771313081593408452016-04-08T23:03:19.994-06:002016-04-08T23:03:19.994-06:00Joe,
I watched with interest your demonstration ...Joe, <br /><br />I watched with interest your demonstration of your rotary shutter and have a couple thoughts about your problem with that one shutter speed where the lens is left exposed.<br /><br />I believe your problem is with the shock absorber. The piston's spring is pushing the shutter backward after impact. What if you had some sort of spring loaded arm sticking up that can only move toward the shock absorber? When the arm passes over the latch, it moves out of the way then the spring brings it back up. After the arm hits the shock absorber, the latch prevents the arm from moving backward. When you want to recock the shutter, just push the latch down so the arm can be brought back to it's starting position.<br /><br />The other idea I have is to completely eliminate the shock absorber and it's spring-loaded piston and replace it with a piece of soft foam rubber. When the arm hits the foam there would be no spring to push the arm backward.<br /><br />Another thought about that shutter speed where you are having problems with the lens being exposed is that the spring powered cord seems to have no energy left at the end of the exposure so it is not putting any tension on the pulley. Somehow there still needs to be enough stored energy where the cord is still pulling on the shutter mechanism that way the shutter would remain closed.<br /><br />I had been thinking of making a Harris / Drop Shutter for my large format camera but what you are doing here might have changed my thinking.<br /><br />Thank you for sharing what you have been working on.<br /><br />Terry Thomas...<br />the photographer<br />Atlanta, Georgia USA<br />TerryThomasPhotos@gmail.comTerry Thomas... the photographerhttps://www.blogger.com/profile/04809283009419422906noreply@blogger.com