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  1. #21

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    Ask any LF photographer, and you'll be told that absence of a focussing mount doesn't mean the lens is meant for fix-focus use.


    (I'm not saying, by the way, that it is an LF lens. Just that a focussing helicoid is not the only way to focus a lens).

    Holes in the lens could really only serve one purpose: cooling or heating.
    Cooling would imply great heat, and that you only get in a projection system.
    Heating would be used to prevent a lens fogging up, which would fit with it being meant for aerial use.

  2. #22
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    Quote Originally Posted by Q.G. View Post
    Ask any LF photographer, and you'll be told that absence of a focussing mount doesn't mean the lens is meant for fix-focus use.
    .
    Indeed, but that would ONE BIG MONSTER bellows system...

  3. #23
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    Im curious I just saw this lens and i was thinking this may not be a projection lens but could this be a small 1940's ground to air war time search light lens? as in for spotting bombers at night?........ my imagination runs wild.
    Last edited by Stephen Frizza; 09-27-2010 at 04:40 AM. Click to view previous post history.
    "Its my profession to hijack time" ~ Stephen Frizza.

  4. #24
    AgX
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    Search lights would not need any complicated lens system. All search lights I know of use a huge (parabolical) mirror and a very small mirror to shield the lamp/burner to the front.

  5. #25
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    I have seen those kind of search lights but i have seen search lights with lens too. though none with a lens like the one shown here. my imagination ran wild because of the holes in the lens.
    "Its my profession to hijack time" ~ Stephen Frizza.

  6. #26

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    Could it be to let water in and out for an underwater lens?
    "There are a great many things I am in doubt about at the moment, and I should consider myself favoured if you would kindly enlighten me. Signed, Doubtful, off to Canada." (BJP 1914).

    Regards
    Bill

  7. #27
    AgX
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    Water would reduce the refractory effect of any glass lens.

  8. #28

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    Quote Originally Posted by cowanw View Post
    Could it be to let water in and out for an underwater lens?
    Um, one of the lens' barrel's jobs is to keep the dark in. The monstrosity's perforations fail miserably at that.

    I have one dive camera. Eumig Nautica, to be exact. Its lens is well sealed. It also has a supplementary w/a lens that screws into the front. Not waterproof, but it doesn't have to be. I've known cavers who used Nikonos cameras; caving is much the same as diving, with a lot of banging around added. Nikonos have well-sealed lenses.

  9. #29
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    There are some underwater cameras that had flooded lenses, I recall, but all of that as small stuff and had problems with the different refractive indices of water or different salinity (as I recall). This thing is far too heavy and would have been far too unwieldy for underwater use anyhow..

  10. #30

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    I doubt that it would be an underwater lens. But can't underpin that believe with reasons.

    The fact that the lens is large and heavy doesn't speak against it. People are doing more going underwater than scubadiving along a reef to take holiday snaps.
    Allowing water into the lens would eliminate pressure problems, which would otherwise require a rather sturdy construction. However, unless you also flood the film or sensor, you will have to have a water barrier at some point. And no better place than at the front end of the optical system (i.e. the front lens), no worse point than somewhere between the lens and the film/sensor.

    That water reduces the refractory index is a given you have to deal with anyway when submerging a camera, AgX. You have to design a lens with that in mind.
    The differing refractive index at different depths and salinity would be a bigger problem in a fixed design lens.

    A bare barrel like this one would appear not to be the whole deal. It is obviously meant to be mounted inside something else, to be pat of a bigger apparatus. And that something else will do a fine job keeping the dark inside. So i wouldn't worry about the wholes from that respect.

    But i still think it is a projection lens.

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