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  1. #1

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    Brownie Camera: focal length?

    Greetings to all members of this amazing Forum.

    Currently, I am conducting a research into some old photographs alleged to have been taken by a 'Kodak (UK) box camera' in 1934. Although I cannot be certain which type of camera was used, I assume that it was one of the following three models:

    - No 2 Brownie Junior

    - Six-20 Brownie Junior

    - Six-20 Brownie Model 4

    Now, I was wondering if you could help me in identifying what was the focal length of the lens used in these models (I understand that most models had simple meniscus, fixed lenses)? This datum seems to elude me despite my many inquiries with professional photographers and searches on the internet. I find it quite odd that none of the manuals from the period, nor specialized websites provide this information. Usually, the only 'specification' available regarding the lens is that it is 'meniscus'.

    I would be very grateful if you could advise me on this particular matter.

    Thankfully,
    Alex
    ----

  2. #2

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    if it is any help...

    some of the hawkeye's had 30mm lenses
    and that might have been 127mm film.
    my guess is that whatever the the box camera was
    the focal length was "medium wide angle"
    yes,very vague, but maybe not too far off

    good luck !
    john

  3. #3

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    Thank you jnanian.

    Yes, I agree that box cameras had 'medium wide angle'. In fact, the landscape in the 1934 photographs I'm investigating does suggest a smaller or medium focal length lens was used. However, while researching the subject I came upon some (seemingly) confusing data. For example, No.2 box Brownie is stated as having a 105 mm lens! But wouldn't such focal length have 'telephoto properties'? Unless, of course, we take into account that a 6 x 9 mm film was used in which case a corresponding equivalent to a 35 mm film would be a 45 mm focal length.

    In other words, does a 105 mm fl in a box camera using 6 x 9 mm film equals to a 45 mm fl for a camera using 35 mm film?

  4. #4
    MattKing's Avatar
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    Quote Originally Posted by Alex_L View Post
    Thank you jnanian.

    Yes, I agree that box cameras had 'medium wide angle'. In fact, the landscape in the 1934 photographs I'm investigating does suggest a smaller or medium focal length lens was used. However, while researching the subject I came upon some (seemingly) confusing data. For example, No.2 box Brownie is stated as having a 105 mm lens! But wouldn't such focal length have 'telephoto properties'? Unless, of course, we take into account that a 6 x 9 mm film was used in which case a corresponding equivalent to a 35 mm film would be a 45 mm focal length.

    In other words, does a 105 mm fl in a box camera using 6 x 9 mm film equals to a 45 mm fl for a camera using 35 mm film?
    "Telephoto" actually means a lens that is physically smaller than its focal length - used most often to permit a longer focal length in a smaller construction.

    A "standard" focal length is usually equal to the diagonal (approximately) of the film format.

    Using modern 35mm film (24mm x 36mm) as an example, 45 mm is approximately standard.

    So a camera that creates 6cm x 9cm negatives (note cm, not mm) would have a "standard" lens that was about 10.5 mm in focal length.
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

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    surely 10.5cm (note cm, not mm)

  6. #6

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    Thanks for correcting me Matt. I did mean to denote cm instead of mm for 6 x 9 film size.

    You said:

    'So a camera that creates 6cm x 9cm negatives (note cm, not mm) would have a "standard" lens that was about 10.5 mm in focal length.'

    You meant 105 mm (or 10.5 cm), right?

  7. #7
    Two23's Avatar
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    I am a Brownie collector. Their lens seems to be 35mm equiv. to something between 45-50mm. I.e., "normal" lens. Since they are fixed focus, couldn't you simply measure from the lens to the plane of the film?


    Kent in SD

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    Quote Originally Posted by Two23 View Post
    Since they are fixed focus, couldn't you simply measure from the lens to the plane of the film?
    Hi Kent,

    Well, no, because I don't have the actual cameras! In my initial post I described I only have photographs from 1934 and the assumption they were made by one of the three models I referred to!

    Hence the reason why I'm asking for the information on this forum.

    Furthermore, I do have a Zeis Ikon (Box Tengor 54/2 model from 1938) and I did some preliminary measurements using two methods:

    (1) I measured the lens to the plane of the film. The result is 105 mm.

    (2) I measured the smallest aperture (f/22) which seems to be almost 3 mm. This would make the focal length about 65 mm.

    So, which is it then, 105 or 65 mm?

    Which method of measuring the focal length is a correct one?

  9. #9
    tony lockerbie's Avatar
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    You can be sure that if they are 6x9 negatives, then the lens would be close to 100mm (or 10cm!) and the others guess of around 105mm would seem correct.

  10. #10
    tony lockerbie's Avatar
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    Just saw your new post, and with that simple lens your first method of measuring is correct.

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