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Thread: Angle of View

  1. #1
    trebor569's Avatar
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    Angle of View

    I need to understand what this phase "angle of view" means in practical terms, and what are the issues if any in Panoramic photgraphy.
    For example a Schneider - Super Angulon XL range has a 110deg of view
    a Schneider - Super Symmar XL range has a 105deg of view
    but none of the manufactures of Panoramic camers have gone for the Symmar range after the 90m Angulon XL lense they all seem to have gone for Schneider - Apo Symmar L with only 75deg of view. Are there technical reasons or just reasons of cost?
    Last edited by trebor569; 09-07-2006 at 10:07 AM. Click to view previous post history.
    [FONT=Palatino Linotype]Rob J-T[/FONT]

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    Angle of view is related to focal length.

    you're looking at angle of coverage.

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    I should add to that. Angle of view is focal length and format.

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    trebor569's Avatar
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    I thought that, but this is not true the apo-symmar have an "angle of view", (I'm using Schnider terms), of 75degrees regardless of focal length but the Super Symmar have 105 degrees, presumably becase they are aspheric lenses.
    [FONT=Palatino Linotype]Rob J-T[/FONT]

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    The angle of view is what the lens is capable of providing at infinity at a specified Fstop...the size of the image circle. Generally, with LF lenses this is either f16 or more commonly f22. Therefore, if you are going to be using a 75º lens on 8x10, that will cover the format it will be a much longer focal lenght than a 110º lens designed to cover the 8x10 format.

    If you have 2 300mm lenses 1 of which is 75º and the other is 110º the 110º lens will provide a much larger image circle. If both were used on a given camera the 110º lens would allow for much greater movement. Both lenses used on axis from the same location would provide identical perspective.
    Claire (Ms Anne Thrope is in the darkroom)

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    Are you referring to panoramic cameras that use 120 film? If so, then there may be no need to use anything other than a lens with a 75° coverage at focal lengths from around 100 mm to 135 mm upwards, the practical minimum length depending on whether it is 6x12 or 6x17 format, and depending on whether or not the camera has shift.

    Best,
    Helen

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    I think of angle of view as the amount that the photo shows, and for traditional cameras would be connection between the focal length of the lense and the format width. A 90 degree angle of view would be just that- seeing 90 degrees from a particular spot. Lense coverage is a whole other thing. It sounds like you are interested in lense coverage, and for panoramic cameras you can fit a longer image in, as it's narrower. For example,a lense that just covers 6x17 (approx 2.25"x7") wouldn't cover 5"x7". For rotating cameras, angle of view is sometimes referred to in relation to the vertical film width and focal length of the lense, as the cameras can often do more than 360 degrees
    Jamie Young

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    trebor569's Avatar
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    Thank you for this link Bruce. It had the following formulae A=2arctan(d/2f)
    and a table informs us that a lense of 180mm will have an angle of view of 13.7degrees.

    Yep I am thinking of 120 film Helen but on a 6x24 fotoman.

    It just stuck me as odd that most of the manufacturers, even on a 6x17, go from the 90/5.6 Angluon XL on to the 180/5.6 Symmar L an switch from a 110 angle to a 75, missing out the 110 & 150 Super Symmar XL and the only thing I can think of is that the latter are twice as expensive, and as you rightly say Claire the XL range has a larger image circle for the same focal length, giving much greater movement and probably a much less noticeable fall of in light. And since fotoman are putting bellows, as an option, on their panoramics I may well need it.

    O, and by the by Helen your photos may be quirky at times e.g. the Tissue box covers, but they are definetly not snaps.
    Thanks all
    [FONT=Palatino Linotype]Rob J-T[/FONT]

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    Justin Cormack's Avatar
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    So long as the lens covers the format the angle of view is not relevant. What matters is the focal length. The super symmars cover much more than you need - the cheaper Symmar Ls cover the format fine. Also Schneider dont sell focussing mounts for the super symmar, which most panoramic cameras use.



 

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