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#11
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Zeiss Ikonta Shutter - Rapid and Synchro - both have flash?
jjs wrote
a shutter that worked only on X. But were there X (electronic) flashes back then? Cough; isn't that a self-answering question? * * * X-only was common as X works with flashbulbs with a suitably slow shutter speed but electronic flash doesn't work with M/FP flashbulb synch. Switchable shutter synch was reserved for high-end gear - Exaktas came with X, M and FP synch and early Leicas had FP and X. Having flash synch was the luxury option. Mamiya Press Seiko shutters came with M and X - usually with the lever set to X and epoxied in place by the last user. Obviously, pre-WWII cameras were predominately bulb-only synch. -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.darkroomautomation.com/index.htm n o lindan at ix dot netcom dot com |
#12
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Zeiss Ikonta Shutter - Rapid and Synchro - both have flash?
"Nicholas O. Lindan" wrote in message
... jjs wrote a shutter that worked only on X. But were there X (electronic) flashes back then? Cough; isn't that a self-answering question? 1930-something? Silly me, I presumed that X meant Electronic flash. I was so wrong for so many years. I just looked at an old shutter here that has a red-faced switch for various flash delays. My old 70mm Graflex military range finder had a big switch for a 20ms delay. I use bulbs but always with long shutter speeds, often B. Mamiya Press Seiko shutters came with M and X - usually with the lever set to X and epoxied in place by the last user. Had my 'blads CLAd and the fellow put a block in the M/X switch to keep it on X. Wish he had not done that. Hey, I have two of the monster Mazda flash bulbs left. Wanna do some night photography? |
#13
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Zeiss Ikonta Shutter - Rapid and Synchro - both have flash?
"Richard Knoppow" wrote in message ... jjs wrote in message ... "Richard Knoppow" wrote in message ... Just never fire a bulb off in your face... YIKES!! I agree about using solenoids for remote tripping. Silent and no limit on distance. Some shutters, particularly the Kodak Supermatic and Flash Supermatic, will not trip at 1/400 with just two batteries and sometimes not with three. This was a problem in the old days and extra-high-voltage photoflash batteries were made for just this purpose. Yup! I know. Radio-Shack, still offer the old 22.5V batteries that those units used. This link shows a camera that used the same. http://www.digoliardi.net/ks6/ I had that set since 1968, and later sold that for a bloody fortune. Sometimes life it good. The 22.5V batteries were used in several BC type flashguns including one of the Rolleiflash units. I don't think they were ever used for solenoid flash. The "high voltage" batteries I was talking about were standard Size-D cells with something special about the mix. They were enough higher than the standard 1.5V so that three of them in a standard flashgun would have enough extra oomph to deal with hard to trip shutters. I don't think these have been made for decades. I don't know what was done to them to increase the voltage but they had a reputation for having short life. When Wollensak came out with the Rapax shutter it was designed to eliminate this problem by having a constant and relatively low "trigger pull" at all speeds. Although Wollensak made some flakey lenses their shutters were always excellent. Begging your pardon, Richard, but I think a solenoid would require high current (amperes), while a flash bulb would require votage. I'd venture to guess that a couple of old-style 1.5V dry cells (about 2" diameter and 6" high with screw cap connections, originally used as "talk batteries" in telephone systems) would pull in most solenoids. Generally with batteries, size/bulk equals current. The larger the cell, the more current it can source, generally. How big a solenoid would it take to trip the old wind-up focal plane shutters in the press cameras?! (The shutter curtain had four different size slits and the was a tension setting to control how fast the slit moved.) |
#14
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Zeiss Ikonta Shutter - Rapid and Synchro - both have flash?
"Ken Hart" wrote in message ... How big a solenoid would it take to trip the old wind-up focal plane shutters in the press cameras?! (The shutter curtain had four different size slits and the was a tension setting to control how fast the slit moved.) Hello, Ken. The solenoids in question are tiny things, about the size of the end of your little finger. It did not wind the FC shutter. It merely tripped the lens' leaf shutter. Here's a most excellent picture of one. Scroll down. http://www.xs4all.nl/~lommen9/GRAFLITE/index.html |
#15
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Zeiss Ikonta Shutter - Rapid and Synchro - both have flash?
"Ken Hart"
but I think a solenoid would require high current (amperes) It's not really current but 'ampere-turns' that are required. If you wrap twice as much wire around the coil you need 1/2 the current. However, when you lower the current requirement you also increase the inductance of the solenoid, and this makes it slow. To make the solenoid faster you can increase the voltage and decrease the wire size to limit the current. The whole thing becomes a 5-way trade-off and you can make a solenoid that works on any voltage and current you wish if you are willing to trade off speed, strength and/or stroke (and cost). while a flash bulb would require votage. It's both voltage and current: volts * amps = power, and it is power that lights off the flash. The bulb can be designed for any voltage desired. Most flash bulbs will fire at 3 volts. The 22.5 V BC (battery & capacitor) flashes were more reliable as they had enough voltage to punch-through any dirt in the bulb contacts or poor contact between the spun wires in the bulb. Because the 22.5 batteries can't deliver much current, the battery charged a capacitor - the capacitor can deliver high current but only for a very short while, which is OK as it only takes a few milliseconds to get a flashbulb ignited. -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.darkroomautomation.com/index.htm n o lindan at ix dot netcom dot com |
#16
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Zeiss Ikonta Shutter - Rapid and Synchro - both have flash?
"Ken Hart" wrote in message ... "Richard Knoppow" wrote in message ... jjs wrote in message ... "Richard Knoppow" wrote in message ... Just never fire a bulb off in your face... YIKES!! I agree about using solenoids for remote tripping. Silent and no limit on distance. Some shutters, particularly the Kodak Supermatic and Flash Supermatic, will not trip at 1/400 with just two batteries and sometimes not with three. This was a problem in the old days and extra-high-voltage photoflash batteries were made for just this purpose. Yup! I know. Radio-Shack, still offer the old 22.5V batteries that those units used. This link shows a camera that used the same. http://www.digoliardi.net/ks6/ I had that set since 1968, and later sold that for a bloody fortune. Sometimes life it good. The 22.5V batteries were used in several BC type flashguns including one of the Rolleiflash units. I don't think they were ever used for solenoid flash. The "high voltage" batteries I was talking about were standard Size-D cells with something special about the mix. They were enough higher than the standard 1.5V so that three of them in a standard flashgun would have enough extra oomph to deal with hard to trip shutters. I don't think these have been made for decades. I don't know what was done to them to increase the voltage but they had a reputation for having short life. When Wollensak came out with the Rapax shutter it was designed to eliminate this problem by having a constant and relatively low "trigger pull" at all speeds. Although Wollensak made some flakey lenses their shutters were always excellent. Begging your pardon, Richard, but I think a solenoid would require high current (amperes), while a flash bulb would require votage. I'd venture to guess that a couple of old-style 1.5V dry cells (about 2" diameter and 6" high with screw cap connections, originally used as "talk batteries" in telephone systems) would pull in most solenoids. Generally with batteries, size/bulk equals current. The larger the cell, the more current it can source, generally. How big a solenoid would it take to trip the old wind-up focal plane shutters in the press cameras?! (The shutter curtain had four different size slits and the was a tension setting to control how fast the slit moved.) Well, you are right that the solenoid draws some current and that minimum voltage is needed to reliably fire the bulb. The problem was that the batteries could not supply enough current for the solenoid when it was used with some hard to trip shutters. This would result in the synch delay being wrong, the shutter not tripping at all or the bulb not firing. What was needed was somewhat greater current capability rather than higher voltage but the pulling power of the electromagnet is the result of both current and voltage. If the supply voltage is increased the current drawn by the soleniod is greater and its pulling force is greater. A problem remains that the delay may shift for the highest speed where the solenoid must work harder to trip the shutter. Generally, I set up solenoids for the highest speed and then check at lower speeds to see if the synch is within the window. Large, high current, batteries, like the No.6 cells you mention might help but would be impractical due to size. Also, keep in mind that there were more than one kind of cell of this type. Telephone batteries were intended for long life where the current draw would be low. Similar batteries were made for ignition of model airplane motors, these were capable of higher current supply where high current but intermittant use was desired. There were also versions made for electric lanterns. I am not sure what a 22.5 volt battery would do to a synchronizer solenoid. If the battery supplies enough currrent it would probably burn it out. BTW, the method I use for setting up solenoids is to use an oscilloscope and watch the trace through the shutter without any lens in it. The scope is set for single sweep and triggered by the trip button, which is what would normally fire the bulb. I use a calibrated sweep and mark the scope face with something to indicate the right delay. I then adjust the solenoid plunger and overall position to give the right delay and strongest force on the trip lever. Two kinds of bulbs were used, Class-F, and Class-M. There were also Class-S bulbs but they were meant for use with open flash, not with synchronizers. Class-F bulbs need a 5 millisecond delay and Class-M bulbs need about a 20 ms delay. The actual delay may vary slightly from this since the ideal is to have the shutter just at its maximum opening when the bulb reaches peak light output. Solenoids were never used for focal plane shutters. There were external synchronizers available "aftermarket" for these. The ones I am familiar with are mechanical and fit over the winding knob on Speed Graphic or Graflex FP shutters. These provide a contact closure. Special, very long duration, bulbs were made for focal plane use, called Class-FP. The duration of the flash was long enough to use with short travel shutters on 35mm cameras but would work on a 4x5 Speed Graphic only at the highest speed (1/1000 second) where the slit travel time was minimum. Another arrangement is used on the Super-D Graflex. This has a built-in flash contact mounted on the shutter curtain. The system can be used with Class-FP bulbs at the highest speed (but has problems when the rotating back is set for "portrait", or, it can be used for strobe using what Graflex called "drop curtain" where the mirror is used as the opening part of the shutter, comes completely open, at which point the flash is fired, and then the FP shutter curtain caps the path. The system has an open time of a bit less than 1/10th second so some care must be used about ambient light. Again, this is completely manual, no solenoid involved. This system works, I've used it for portraiture especially for kids. Even though shutters with built-in synchronization became available around the late 1940's many press cameras still had solenoids installed. This was partly because the solenoid provides a convenient method of remote tripping and partly because its use doesn't require the second cocking operation required by the Kodak and Ilex synch shutters which were common on a lot of Speed Graphics. When I was first introduced to the Speed Graphic back in highschool I often used the solenoid strictly for tripping the shutter but connected the bulb through the shutter contacts. All of the late Graflex flashguns allow this arrangement. Press photographers may not be very welcome now but at least people don't have to deal with fried and broken flashbulbs all over the place. Pop, sizzle, crunch... -- --- Richard Knoppow Los Angeles, CA, USA |
#17
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Zeiss Ikonta Shutter - Rapid and Synchro - both have flash?
"Richard Knoppow"
BTW, the method I use for setting up solenoids is to use an oscilloscope and watch the trace through the shutter without any lens in it. The scope is set for single sweep and triggered by the trip button, which is what would normally fire the bulb. I use a calibrated sweep and mark the scope face with something You can also used the delayed sweep/intensified and set the end of the intensified bit so it is where the shutter is to open. The synch is set when you can see just a little bit of the intensified sweep. at least people don't have to deal with fried and broken flashbulbs all over the place. Pop, sizzle, crunch... For me, the smell of cooked flashbulbs invokes nostalgia. I think I will go fire one ... though I don't know if I still have a flash attachment. -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.darkroomautomation.com/index.htm n o lindan at ix dot netcom dot com |
#18
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Zeiss Ikonta Shutter - Rapid and Synchro - both have flash?
"Nicholas O. Lindan" wrote in message ... For me, the smell of cooked flashbulbs invokes nostalgia. I think I will go fire one ... though I don't know if I still have a flash attachment. If you really like the smell of flashbulbs, I currently have on auction (on a well-known website) a device made by Konica. It mounts in a hot shoe, has a 22.5 volt battery, and holds a flashcube. I wonder if this device ever really sold in any quantity. Were flashcubes more economical than AG-1 bulbs? Obviously they were more convenient, but the AG-1 efficiency surely could have been better (depending on the flashgun) whereas the flashcube had such a small reflector. As for nostalgic smells, personally, RA-4 chemistry does it for me. That's why I built the bedroom directly above the darkroom! |
#19
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Zeiss Ikonta Shutter - Rapid and Synchro - both have flash?
"Nicholas O. Lindan" wrote in message ... "Ken Hart" but I think a solenoid would require high current (amperes) It's not really current but 'ampere-turns' that are required. If you wrap twice as much wire around the coil you need 1/2 the current. However, when you lower the current requirement you also increase the inductance of the solenoid, and this makes it slow. To make the solenoid faster you can increase the voltage and decrease the wire size to limit the current. The whole thing becomes a 5-way trade-off and you can make a solenoid that works on any voltage and current you wish if you are willing to trade off speed, strength and/or stroke (and cost). A 5-way trade-off? I can deal with E=IR and "ELI the ICEman, but a five way trade? Would that be a pentratradic equation? while a flash bulb would require votage. It's both voltage and current: volts * amps = power, and it is power that lights off the flash. The bulb can be designed for any voltage desired. Most flash bulbs will fire at 3 volts. The 22.5 V BC (battery & capacitor) flashes were more reliable as they had enough voltage to punch-through any dirt in the bulb contacts or poor contact between the spun wires in the bulb. Back in my college days, (Pennsylvania Governor's School for the Arts at Bucknell University), we used to sneak into a dorm room, remove the light bulb from the ceiling fixture and screw in a flashbulb (#5?). Then we waited for the occupant to return. 110V was plenty of voltage to fire those things! |
#20
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Zeiss Ikonta Shutter - Rapid and Synchro - both have flash?
"Richard Knoppow" wrote in message ... snip Press photographers may not be very welcome now but at least people don't have to deal with fried and broken flashbulbs all over the place. Pop, sizzle, crunch... -- --- Richard Knoppow Los Angeles, CA, USA In one post, you have commented (correctly) on: 1. Electronics theory 2. Obscure cells 3. Voltage smoke-testing (!) 4. Electronics test procedures as related to camera repair/adjustment 5. Flash bulbs and the history thereof 6. Press cameras 7. Flash synchronization through the ages 8. Social acceptance of representatives of the print media. ("Press photographers may not be welcome...") You, sir, are a god! When I grow up, I want to be you-- ! |
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