| T O P I C R E V I E W |
| Jo Lund |
Posted - Jun 09 2013 : 3:48:54 PM
Hi to you all,
I don't know if a shutter with 1 second or longer exposure times has been made in the USSR?
The photoemulsion I use is not quite fast enough for the shutterspeeds of my Fotokors.
If I remember correctly there was also an accesory enabling longer shutter times available.
Of course B and T Settings are usable, but not that accurate.
Thanks a lot
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| 4 L A T E S T R E P L I E S (Newest First) |
| Jo Lund |
Posted - Jun 10 2013 : 4:39:45 PM
Hi Ralph,
Thanks for all the information you gave. I have a couple of old cameras from 1903 up to the mid fifties. All the shutters are unreliable, but if from the start a considerable aberration of the given speeds was more or less standard then I just have to take some shots to know what difference in speed really exists.
Looking at my mid sixties Asahi Pentax S3 X contact it is between 30th and 60th of a second. I remember however always using a bulb flash at a 15th.
Coming week end Í'll take the first shots with the Fotokors on homemade plates. I'll publish them in the Gallery here I think.
Ralph, by the way, I have to stop using these silly "cover up names"
I had high hopes of keeping my identity secret. By Blogging and publishing on the Light Farm and Apug these incognitos are blown already. Sorry,
Thanks again,
Henk Mantel
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| Ralph J |
Posted - Jun 10 2013 : 11:02:15 AM
Good morning, Jo Lund;
Four (4) things:
First; please accept my apologies for my confusion over your name. Now, belatedly, I should ask; "What name do you prefer that we use when talking with you?"
Second; how nice to hear that there really are people making their own photographic emulsion. Ron Mowery, Photo Engineer on APUG, and who used to work for Eastman-Kodak, will be pleased to hear that people really are doing this, and perhaps they are even using his book on that topic. With the loss of so many films, and even film makers, it is good to see that others are doing things that will in some way see that we can still use our cameras in the years to come, in spite of the varying financial fortunes of so many companies. I can also make glass plates for use with the SINAR and Speed Graphic 5 by 4 Large Format cameras.
Third; Yes, working with a very slow speed light sensitive material can be interesting. As mentioned, I use the ADOX CMS-20 and slow it down even more to ASA 5 when testing very fast lenses. The ADOX film has exceptional resolution, and I make my tests with the 1951 USAF Lens Resolution Test Targets outside in full sunlight, because that lighting condition is repeatable and reproducible by others wherever they may be. In that way it may be possible to directly compare one person's test results with another's, if we are also using the same film with the matching ADOX developer. And only by using a very slow film can we take a photograph outside using a normal camera with the common shutter speeds that go up to only 1/1000th of a second. Yes, there are cameras with maximum shutter speeds higher than 1/1000 second, but they may not be as common, and often they are more expensive also. For example, the Minolta Dynax 9 or Maxxum 9 does go up to 1/12,000th of a second, but they are not common, and when they are found available on the used market, they are expensive.
Testing lenses can be a challenge, and there are so many things to look for. With all of the possible aberrations, it is a wonder that we can take any sort of a clear and sharp photograph.
Fourth; The ASA (now ANSI) Shutter Testing speed tolerance for allowable errors in shutter speeds of 1/500 second and faster rises to plus and minus forty percent (40%). Most of the electronic shutters that I have tested are very good, and the Copal Square Metal Blind Vertically Traveling Shutter has proven to be remarkably accurate and consistent on the Kyoritsu EF-511NK1 Camera Tester.
One funny quirk about the Copal Square is the 1/125 second shutter speed. Back in the 1960s when the Copal Square shutter came out, it was advertised as the first focal plane shutter with a 1/125 second X sync speed for use with electronic flash units, while the more common cloth blind focal plane shutter had an X sync speed of only 1/50 or 1/60 second. But, every Copal Square shutter that I have tested, and that other professional camera technicians have tested, all come out right at just shorter than 1/100th of a second; usually right around 98 or 99 milliseconds. Every one of them. It seems that this was actually a case of a little bit of advertising or marketing license, and they were really playing with that 20% allowable speed error with their shutters and the "claim" of a 1/125 second X sync speed.
Enjoy;
Ralph
Latte Land, Washington |
| Jo Lund |
Posted - Jun 10 2013 : 07:02:29 AM
Hi! Ralph,
Sorry for being a bit vague in my question. I still am translating Dutch into English.
Thanks for the info about the allowed unpreciseness in the calculation of exposure times.
Concerning the film I use. Well, I am busy making my own emulsions and I am about to make my own 9X12 cm plates. The speed of the emulsion is something I have to figure out, but it will be around 5 ASA.
It is all very challenging but a lot of advice and support comes from The Light Farm in Oregon. I wrote a couple of stories for them, explaining my first endeavors in emulsion making.
Very nice people they are, and not that far away from your place.
http://www.thelightfarm.com/
Thanks again and I'll give exposure timing a try with my watch.
Henk
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| Ralph J |
Posted - Jun 09 2013 : 6:13:12 PM
Good morning, Henk Mantel;
I am not sure that I fully understand the question. First, yes, there are FSU cameras with a shutter speed of one full second. I have the KMZ Zorki-4 and the Zorki-4K, both of which have a one second shutter speed.
Second, I do not know of any accessory that would provide longer shutter speed times. I can see how something could be built that would work with the "B" setting on the shutter speed dial, but I have never seen one.
The only thing at all like what you are describing that I have seen and I do have samples here for doing it, are the shutter release time delay devices that give you usually about a 10 second to 15 second time delay before extending a pin to go into the cable release socket on the camera to release the shutter and take a photograph at whatever shutter speed setting was chosen on the shutter speed dial.
For longer exposure times, such as two seconds, five seconds, and similar long exposure times, I have found that my watch is quite adequate for guiding me and getting the long exposure time that I want. Please note that the ASA Photographic Shutter Speed Testing Standard does allow for a variation of Plus or Minus Twenty Percent (20%) on the shutter speeds of 1/400th second and longer. I have been able to meet that tolerance specification very easily at 2 seconds and longer.
And, please tell me what film or film emulsion you are using that is slow enough to require normal exposure times on the order of one full second in time or longer? Or are there unusual lighting conditions that require these long exposure times?
At this time, the slowest film that I have been able to find, and the one I use for lens testing, is the ADOX CMS-20 with an ASA/ISO speed rating of 20, and I slow it down to ASA 5 for my testing of f:1.4 aperture lenses with a camera that all of us can buy.
Enjoy;
Ralph
Latte Land, Washington |
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