Page 2 of 9 FirstFirst 1234 ... LastLast
Results 11 to 20 of 88

Thread: Speed Graphic Focal Plane Shutter

  1. #11

    Join Date
    Dec 2009
    Location
    Minnesota
    Posts
    68

    Re: Speed Graphic Focal Plane Shutter

    I know that I had similar difficulty when testing my Speed. My light source was too big and my sensor was way too far from the FP shutter. Switched to a very focused beam (sounds like you did a similar thing with the soda straw) and moving the sensor closer to the FP to mimic the film plane made a huge difference in my measured speeds. My 1/1000 tests out at 1/500 and 250 and below is close enough for my work. Try using a laser pointer--very little scatter. I also thought about using the flash sync conductors on the FP to time the speed of the curtain and do the math to figure out the accurancy but then I decided to just get out and shoot--way more fun.

  2. #12

    Join Date
    Dec 2009
    Location
    Minnesota
    Posts
    68

    Re: Speed Graphic Focal Plane Shutter

    On second thought would an engine timing light work?

  3. #13
    multi format
    Join Date
    Feb 2001
    Posts
    2,791

    Re: Speed Graphic Focal Plane Shutter

    rick

    did you take the body cap off the end of the roller shutter and put a drop of oil
    on the end of the rod? ( be careful not to get any on the shutter itself)
    that sometimes helps to make things run smoothly.
    ( i noticed a difference before and after when i did that with my slr ) ..

    did you try to get the 1/30th S nailed with the camera upside down
    and see where the rest of the speeds ended up ? it might be just enough
    of a difference that the other speeds are a 1/2 stop- off instead of a full stop+.

    calumet testers work OK with the lens removed. i have a friend who used his industrial-grade
    shutter tester at his repair shop and we removed the lens and just held the probe
    ( series D slr ) i would imagine a speed graphic would test the same way, seeing
    his fancy tester was pretty much the same thing as a calumet tester, except
    it came with a light source ( 2 -3 feet away) to point the camera at,
    and something to rest/sit the camera on while it was being tested.
    we didn't have anything to block the light, or anything like that
    one of us held the sensor around where the film plane was, and the other one
    wound and released the shutter. needing to be someone with 4 arms was the hard part.

    john

  4. #14
    Moderator
    Join Date
    Apr 2009
    Location
    Northern Virginia
    Posts
    4,352

    Re: Speed Graphic Focal Plane Shutter

    Quote Originally Posted by jnanian View Post
    did you take the body cap off the end of the roller shutter and put a drop of oil on the end of the rod? ( be careful not to get any on the shutter itself) that sometimes helps to make things run smoothly. ( i noticed a difference before and after when i did that with my slr ) ..
    Yes, I took both caps off, and I also cleaned the ends of the curtain shafts and swabbed out the bushings in those caps before applying a touch of the light grease as the service manual specifies. Same on the shutter mechanism side. The curtain seems to move smoothly enough, but I still haven't tested it (my testing today didn't get past the front shutters).

    I wouldn't know where to begin to adjust the 1/30 speed. The governor is not adjustible, and the only way I can think of to adjust the curtain speed is to tighten up that spring even more. But that had no effect--I stopped tightening when doing so stopped having an effect.

    The governor is just a spinning centrifugal brake--no adjustment capability. And though the manual provided troubleshooting procedures, it did not provide any means I could find of actually adjusting the speeds. Seems that if everything is right, so are the speeds. Therefore, something must not be right in mine. But there are still some usable speeds, except that I really wish the rear shutter went down to 1/4, which is just a hair fast for manual timing, at least for me.

    I have experience with a Calumet tester that I borrowed from Dan Unkefer a few years ago for long enough to test a bunch of Second-World cameras. I found that the light source for it was quite sensitive. I ended up using a battery-power flashlight placed enough distant to just trigger the tester, and shining through the shutter without a lens. The diode tester is a lot more forgiving. I get basically the same results using any incandescent or window light that is sufficient to saturate the diode. Unless the fall delay is substantially longer than the rise delay, the diode tester should be correct if one knows where on the waveform to measure. The Calumet tester does measure fast shutter speeds correctly, but only if the light source is just bright enough to trigger it.

    Rick "enjoying the project" Denney

  5. #15
    Moderator
    Join Date
    Apr 2009
    Location
    Northern Virginia
    Posts
    4,352

    Re: Speed Graphic Focal Plane Shutter

    It finally occurred to me to check the shutter tester against a proven focal-plane shutter. So, I pulled out my Pentax 6x7, which uses electronic timing for closing the second curtain. The timer is accurate--at speeds of 60 and slower the shutter speed measured within five percent. 1/15 was worst at a measured speed of 1/15.7. But that is unpersuasive--the maximum error is still .003 seconds, which is too much for the fast speeds.

    And 125 measured 114, 250 measured 200, and 1000 measured 435. (I forget what 500 was.) I think the wave shape seen from a photodiode through a sound card is just too hard to interpret with sufficient accuracy at speeds of 250 and higher, and perhaps even 125 and higher. Given where most of us live in terms of shutter speeds, this is no weakness at all. The fastest shutter speed I can use with 100-speed film is about 125, unless I happen upon a lens with a useful aperture larger than f/5.6, heh.

    Rick "who just realized this project is complete" Denney

  6. #16

    Join Date
    Mar 2002
    Location
    Sweet, ID
    Posts
    406

    Re: Speed Graphic Focal Plane Shutter

    Quote Originally Posted by Mattk View Post
    On second thought would an engine timing light work?
    and hooked up how?
    The only trouble with doin' nothing is you can't tell when you get caught up

  7. #17
    JoeV's Avatar
    Join Date
    Oct 2006
    Location
    Albuquerque, NM, USA
    Posts
    155

    Re: Speed Graphic Focal Plane Shutter

    Quote Originally Posted by Paul Metcalf View Post
    and hooked up how?
    To the ignition coil on the flash connector bracket, of course!

    ~Joe

  8. #18

    Join Date
    Dec 2005
    Location
    Southern California
    Posts
    2,698

    Re: Speed Graphic Focal Plane Shutter

    Rick, why don't you try what Brian suggested - shoot a series of exposures on a calibrated film and measure the resulting densities? Maybe even take a control series of shots with a known shutter on the same setup for good measure?

  9. #19
    Moderator
    Join Date
    Apr 2009
    Location
    Northern Virginia
    Posts
    4,352

    Re: Speed Graphic Focal Plane Shutter

    Quote Originally Posted by Marko View Post
    Rick, why don't you try what Brian suggested - shoot a series of exposures on a calibrated film and measure the resulting densities? Maybe even take a control series of shots with a known shutter on the same setup for good measure?
    That was my plan, as hinted above. Given that I don't do black and white any more, and have no darkroom, profligate experimentation is expensive, so I was trying to answer the obvious questions first.

    Rick "and the use of slow film and tessar lenses suggests rare needs for fast shutter speeds" Denney

  10. #20

    Join Date
    Dec 2005
    Location
    Los Angeles, CA
    Posts
    3,845

    Re: Speed Graphic Focal Plane Shutter

    Rick,

    You can do the same with color film... but I know you know that.

    I actually prefer to test like this using E6 since I can drop it at the lab and have it back in 3 hours.

    But I wouldn't consider one (or even two) roll(s) of film(s) to be "profiligate experimetnation(s)", but thanks for the Word of the Day!
    Last edited by BrianShaw; 1-Jun-2010 at 08:29. Reason: I had to look it up in the Dictionary... what an illiterate moron I must be!

Similar Threads

  1. Handheld 4x5- Razzle and Speed Graphic
    By Chris Usher in forum Cameras & Camera Accessories
    Replies: 44
    Last Post: 16-Apr-2008, 22:16
  2. Replies: 7
    Last Post: 23-Jul-2007, 07:10
  3. 8X10 Focal Plane Shutter shaft and spring??
    By Simon Benton in forum Cameras & Camera Accessories
    Replies: 1
    Last Post: 20-Feb-2007, 11:46
  4. Educate me on Graphics please
    By Photomax in forum Cameras & Camera Accessories
    Replies: 21
    Last Post: 15-Feb-2007, 07:57

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •