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Thread: Aerials: 125-150mm sharp@ f/8 for 4x5 minimal vignetting

  1. #31

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    Re: Aerials: 125-150mm sharp@ f/8 for 4x5 minimal vignetting

    The RF101C could take up to 6 cameras at a time. Most of the stuff we handled were from the Fairchild KA45 or similar 4.5 x 4.5 cameras. They did not have motion compensation except for some of the pano cameras which shot horizon to horizon on one long frame.

  2. #32

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    Re: Aerials: 125-150mm sharp@ f/8 for 4x5 minimal vignetting

    Quote Originally Posted by jp View Post
    Bob; I love these stories! First person cold-war history. I was too young for most of it but love history and technology and sometimes get to hear really interesting stories (like this) from people who applied their ingenuity and quick thinking in our defense.
    Thanks, I served in an interesting period. I went into the AF a few months before Cuba and, as my father had a major heart attack, had applied for a hardship family medical discharge the morning of the Tonkin Gulf incident. As the unit I was in was part of the Composite Air Strike Force which included a Navy, a Marine and an Army component we were expected to be able to deploy to any location within 72 hours, worldwide. As such we were supposed to have pre packed duffle bags for jungle, arctic and temperate areas.
    The night of the Gulf incident my wife and I were watching Johnny Carson when one of the NCOs knocked on the door and said that there was an alert and to take the jungle duffle.
    At the base the squadron was boarding a transport plane and as I was walking up the ramp the squadron operations officer asked if I had applied for discharge that morning. I told him I had and he pulled me off the flight, told me I could no go anywhere until the application was operated on and I could go back home.
    That plane went to Thailand and I was discharged a few days later.

  3. #33

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    Re: Aerials: 125-150mm sharp@ f/8 for 4x5 minimal vignetting

    Quote Originally Posted by Jac@stafford.net View Post
    To add to our history, I was in the the same mission, same years, same aircraft: RF101 Voodoo and RB66 as Bob Salomon.

    But I earned the Presidential Unit Citation much earlier.
    Actually I misspoke. Kennedy gave us the Presidential Outstanding Unit award. Not sure if that is the same or different then the Unit Citation.

    Were you at Shaw also?

  4. #34
    Dave Karp
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    Re: Aerials: 125-150mm sharp@ f/8 for 4x5 minimal vignetting

    Bob (and Jac),

    That was more interesting than the main topic (at least to me). Thanks!

    Have you thought about giving an oral history? I think that there are different options. My dad was asked to give one at the local VA hospital. Perhaps local universities?

  5. #35
    Jac@stafford.net's Avatar
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    Re: Aerials: 125-150mm sharp@ f/8 for 4x5 minimal vignetting

    Quote Originally Posted by Bob Salomon View Post
    Were you at Shaw also?
    Toul Rosiers, France and
    RAF Upper Heyford, England

  6. #36

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    Re: Aerials: 125-150mm sharp@ f/8 for 4x5 minimal vignetting

    Quote Originally Posted by Bob Salomon View Post
    you can make out all of the details on the stacked AK47 rifles stacked before a camp site as we approached.
    Quote Originally Posted by Dan Fromm View Post
    motion blur depends on the altitude, lens' focal length, and ground speed.
    Well, in reconnaissance an important parmeter is the on "ground motion blur", this depends only (if no compensation) on shutter speed and ground speed, and it tells what object size we can see because blur. At Mach 1.0 this is 340m/s, so at 1/1000 shutter we have 340mm ground blur. At Mach 0.5 this would be 150mm of motion blur at real ground object scale, so the AK-47 stacks had to be seen.

    Given the flight altitude and the focal we can calculate the "on film blur", this is the "on ground blur" divided by the magnification. If Magnification is 1:5000, then those 150mm of ground blur will be 0.03mm of motion blur on film, so limiting resolution to some 15 Lp/mm, so we can go x3 higher with the plane and still motion blur not degradating what sharp film/optics can capture, or using a 1/3 of the focal length at same altitude....

    At the end the ground motion blur will determine the size of the field that the photograph can record without degradating what motion blur allows...

    I make that kind of calculations often, but with an industrial camera looking moving products, it's just the same easy calculation. In fact I got the theory from aerial photography handbooks...

  7. #37

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    Re: Aerials: 125-150mm sharp@ f/8 for 4x5 minimal vignetting

    Quote Originally Posted by Jac@stafford.net View Post
    Toul Rosiers, France and
    RAF Upper Heyford, England
    Lucky you! I got orders transferring me PCS from Shaw to Nancy. But my wife was just over 6 months pregnant with our first one and regulations barred foreign transfers if your wife was 6 months, or more, pregnant. But since I could not be sent I had to volunteer for a change of station after she had the baby.
    Since my father in law was born in Nancy my wife and I really wanted to go there. So I volunteered for Nancy, Heidleburg, Wiesbaden and Bermuda.
    Instead we got sent to Hurlburt Field at Elgin.

  8. #38

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    Re: Aerials: 125-150mm sharp@ f/8 for 4x5 minimal vignetting

    Quote Originally Posted by Pere Casals View Post
    Well, in reconnaissance an important parmeter is the on "ground motion blur", this depends only (if no compensation) on shutter speed and ground speed, and it tells what object size we can see because blur. At Mach 1.0 this is 340m/s, so at 1/1000 shutter we have 340mm ground blur. At Mach 0.5 this would be 150mm of motion blur at real ground object scale, so the AK-47 stacks had to be seen.

    Given the flight altitude and the focal we can calculate the "on film blur", this is the "on ground blur" divided by the magnification. If Magnification is 1:5000, then those 150mm of ground blur will be 0.03mm of motion blur on film, so limiting resolution to some 15 Lp/mm, so we can go x3 higher with the plane and still motion blur not degradating what sharp film/optics can capture, or using a 1/3 of the focal length at same altitude....

    At the end the ground motion blur will determine the size of the field that the photograph can record without degradating what motion blur allows...

    I make that kind of calculations often, but with an industrial camera looking moving products, it's just the same easy calculation. In fact I got the theory from aerial photography handbooks...
    This reminds me of when we sold the first Linhof Aero Technika 45 EL cameras to NASA for the Navy to use on the Space Shuttle.
    After they used it on their first mission that required it I got a call from the Astronauts that used it. Their comment was that when they shot the target on Hasselblds they knew something was there. But when they shot it with the Linhof they then knew exactly what it was!

  9. #39

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    Re: Aerials: 125-150mm sharp@ f/8 for 4x5 minimal vignetting

    Love the history. I’m just a farm boy with a camera. I can shoot handheld digital FF with a 50mm forward and back (clearing the prop, wing, strut, landing gear, and tail) in a Cessna 172 and get consistent clear shots 1/500 f/8 without a gyro, although I have Kenyon, I rarely use it as I like to work with two cameras, namely one with 50mm and one with a 28mm (again FF “35” equivalents.”). Also I like to shooot both verticals and horizontals in quick succession.

    I thought I would drag along a 4x5 and play with it, hence the post. If I ever hitch a ride in SR-71 or space launch, I will remember the dissertation cited and FMC. I really enjoy working with good pilots to have an optimal approach to the target area and to have the aircraft in good attitude for angle-of-view clearance an minimal vibration. Barnyard common sense.

    I may start with a slightly longer lens ie Nikkor 200mm M f/8. I believe that wide open, the image circle is 166mm. If anyone has real life experience with that lens in terms of coverage - and corner sharpness (a long shot, I know) - at f/8 let me know.

    ps: my dad flew combat as a pilot in 2 wars and was a USAF test pilot at Edwards and Wright-Patt. 2 Air Medals, several DFC,s w Oak Clusters. RIP. Thanks to all who served. I fished in a pond on a SAC base and watched Voodoo’s and B-52’s take off.
    Dallas Texas HABS / HAER / HALS Photography
    Photographer/Author Marfa Flights: Aerial Views of Big Bend Country (Texas A&M University Press)
    Petroleum Oil Pics

  10. #40

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    Re: Aerials: 125-150mm sharp@ f/8 for 4x5 minimal vignetting

    ps: asked Santa for a Zeiss Planar 135mm f/3.5 But no-go. Must have been the numerous naughty moments over Big Bend
    Dallas Texas HABS / HAER / HALS Photography
    Photographer/Author Marfa Flights: Aerial Views of Big Bend Country (Texas A&M University Press)
    Petroleum Oil Pics

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