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Thread: 2017 Solar Eclipse

  1. #1
    jesse1996's Avatar
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    2017 Solar Eclipse

    Hello All! with the anticipated solar eclipse coming up 21 August this year. Does anyone have any experience with shooting this event with 4x5 or 8x10 film? It seems like there a lot of aspects about it that I'm having a hard time pulling up information on. Any help is really appreciated!

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    Thalmees's Avatar
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    Re: 2017 Solar Eclipse

    Quote Originally Posted by jesse1996 View Post
    Hello All! with the anticipated solar eclipse coming up 21 August this year. Does anyone have any experience with shooting this event with 4x5 or 8x10 film? It seems like there a lot of aspects about it that I'm having a hard time pulling up information on. Any help is really appreciated!
    Hello jesse,
    Protect your eyes.
    Good luck.

    The generosity of spirit in this forum is great, its warmly appreciated.
    ------------------------------

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    Re: 2017 Solar Eclipse

    Kodak produced a helpful booklet with the title ASTROPHOTOGRAPHY BASICS AC-48 and there are about eight pages devoted to solar eclipse photography, it is long out of print, see if you can locate a used copy.

    One aspect that deserves some consideration is the choice of lens. The sun is a small object, about half a degree across, which means that the use of a normal length lens will produce a very small image. When a larger image is wanted, perhaps one quarter to one third of the size of the frame, then the lens focal length required may be more than ten times normal, perhaps 1m - 2m for 4x5 and double that for 8x10. This is a very large lens and requires special mounting arrangements. Much astrophotography is done using telescopes of long focal length where the camera is attached to the telescope.
    Last edited by Ted R; 2-Apr-2017 at 18:42.

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    jesse1996's Avatar
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    Re: 2017 Solar Eclipse

    you think its possible to gerrymander a telescope made from PVC pipe or something like that with the lens attached at the other end?

  5. #5
    8x10, 5x7, 4x5, et al Leigh's Avatar
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    Re: 2017 Solar Eclipse

    With only two exceptions, my wife has watched every eclipse that's happened anywhere over the last 50 years.
    She shot most of them, using 35mm, not LF, with focal lengths out to about 250mm.

    The size of the sun's image on the film depends exclusively on the lens focal length, not the film format.

    Fred Espenak published a table of sun image size v. lens focal length. Excerpts:
    105mm = 1.0mm
    200mm = 1.8mm
    500mm = 4.6mm (~0.2 inches)

    But you're going to have other problems, such as keeping the sun centered in the frame as it moves.
    All work except totality MUST be done with a solar filter over the lens. It's extremely dense.

    Also, you need to have the camera on an equatorial mount, not our common az-el mount.
    An equatorial mount has the rotational plane parallel to the earth's equator.
    That's because the sun traverses the plane of the ecliptic from our viewpoint, and in fact defines same.

    - Leigh
    If you believe you can, or you believe you can't... you're right.

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    tgtaylor's Avatar
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    Re: 2017 Solar Eclipse

    Difficult to do but you could capture the various stages of the eclipse on one sheet of film (I'd use 8x10).

    Thomas

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    Jim Jones's Avatar
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    Re: 2017 Solar Eclipse

    Quote Originally Posted by jesse1996 View Post
    you think its possible to gerrymander a telescope made from PVC pipe or something like that with the lens attached at the other end?
    Yes. The biggest problem may be in finding a quality lens of adequate focal length. Lacking that, you can always take pinhole images of the eclipse. This also eliminates the necessity of using a solar filter for most exposures. Long ago I tried to photograph a solar eclipse with a 32-foot-long pinhole camera made out of black plastic tubing. It was too cumbersome, but worked well enough when shortened to 24 feet. The front of the camera was suspended from a telephone pole, and the film end held by hand and moved until it was centered on the shadow of the front end. Another way of operating such a long camera is to rest the rear on the ground and manipulate the tube to center its shadow on the film end. With a little more work, a finder could be improvised. A string operated an old Prontor shutter. As I recall, the pinhole was about .070" in diameter, and yielded a quite fuzzy image. Better than a pinhole may be a .25 diopter close-up filter. Don't wait until the last month before improvising and testing such a camera. Plastic tubes flex: even the 24 foot tube required bracing.

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    Jim Jones's Avatar
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    Re: 2017 Solar Eclipse

    Quote Originally Posted by Leigh View Post
    . . . But you're going to have other problems, such as keeping the sun centered in the frame as it moves.
    All work except totality MUST be done with a solar filter over the lens. It's extremely dense.

    Also, you need to have the camera on an equatorial mount, not our common az-el mount.
    An equatorial mount has the rotational plane parallel to the earth's equator.
    That's because the sun traverses the plane of the ecliptic from our viewpoint, and in fact defines same.

    - Leigh
    Except for totality, a solar filter is needed somewhere in the optical path, but not necessarily in front of the lens. A sheet of film completely exposed and developed and double loaded in front of the raw film in the holder makes an expensive solar filter. Experiment long before the day of the eclipse.

    An equatorial mount may be necessary only during those few minutes of totality. Otherwise, the fast shutter speeds usually necessary for photographing the Sun should stop its apparent movement.

    Thomas Taylor's suggestion of capturing the entire event on one sheet of film is practical, although time consuming and perhaps difficult. I captured part of a lunar eclipse at intervals of 2 minutes on a Speed Graphic. This bunched the individual moon images awfully close, but it worked since part of the moon was unlit. 4 or 5 minutes might be better for the Solar eclipse. The entire Solar eclipse event lasts over two hours. Getting all of it on one piece of film without any glitches involves much luck or very good preparation. An intervalometer would help.

  9. #9
    8x10, 5x7, 4x5, et al Leigh's Avatar
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    Re: 2017 Solar Eclipse

    Quote Originally Posted by Jim Jones View Post
    Except for totality, a solar filter is needed somewhere in the optical path, but not necessarily in front of the lens.
    A solar filter is required between the sun and the film AND between the sun and your eyes.
    That's true even if you are viewing the sun's image on a ground glass.
    Depending on the camera configuration, this may be most easily done with a filter over the lens.

    Quote Originally Posted by Jim Jones View Post
    An equatorial mount may be necessary only during those few minutes of totality. Otherwise, the fast shutter speeds usually necessary for photographing the Sun should stop its apparent movement.
    The equatorial mount makes it easier to pan the camera while tracking the sun.

    -Leigh
    If you believe you can, or you believe you can't... you're right.

  10. #10

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    Re: 2017 Solar Eclipse

    I'll be reading with interesting-I may take the day off work and head down to "ground zero" in Hopkinsville.

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