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  1. #1
    George Papantoniou's Avatar
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    Have to expose for 1 hour in daylight...

    I want to make pictures in plain daylight (cloudy day) with my Linhof 4x5 but I need to have REALLY long exposure times... (1 hour). I need normal contrast negs for printing...

    One thought was to expose Ilford ortho film with a red filter. Do you think this would allow me to expose for an hour with say, an f16 or f22 ? I guess the red filter for the ortho film will be much stronger than an ND for a panchromatic one...

    On the other hand I can put several ND's one on top of the other, but then I risk vignetting (too many screw-on filters) and they will cost me a fortune to buy...

    I could use an IR filter but I don't know if there will be anything on the film (even if I use a pan film).

    Are there any more ideas ??

  2. #2
    Ole
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    When we had a partial solar eclipse a few years ago, I shot it with APX100 and an IR filter (Lee gel). 1 second at f:8 was spot on - for the sun itself.

    But it all depends on the spectral response of the film, the spectral transmission of the filter, and... It's almost impossible to predict. Especially if you don't have APX 100, which I have used that way once.

    Very slow film and dense ND filters are the best bet.
    -- Ole Tjugen, Luddite Elitist
    Norway

  3. #3
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    Hi George,

    You don't say what you're trying to achieve. Could you get an acceptable result via multiple exposures over a period of time?

    All the best,

    Frank
    The destination is important, but so is the journey

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    Mongo's Avatar
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    Any particular reason you don't want to stack ND filters? I'd think that would be the easiest way to get where you want to go...not, perhaps, the best way optically, but in a 1 hour exposure even shadows will move significantly so a little optical degredation shouldn't be awful.

    Best of luck.
    Dave
    Film is cheap. Opportunities are priceless.

  5. #5

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    You can buy sheets of ND material pretty cheap and make your own "stacked" filters. It will save you money, avoid vignetting, and allow you to experiment without too much cost.

  6. #6

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    Don't stack too many filters. There are very dense ND filters made, B+W makes 10, 13 and 20 stop ND filters. They may be special order items but they are available.

  7. #7
    jimgalli's Avatar
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    I have a photo of waves coming in around rocks that I did at 7 minutes with 100 asa film in daylight with just a 29 red and a polariser. With Efke 25 film that could have gotten up in the hour range pretty quicly with reciprocity. If the ortho film is true ortho you could leave a red filter on forever and get a blank sheet. There's always pinhole.
    He is no fool who gives what he cannot keep..to gain that which he cannot lose. Jim Elliot, 1949

    http://tonopahpictures.0catch.com

  8. #8

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    Quote Originally Posted by George Papantoniou
    I want to make pictures in plain daylight (cloudy day) with my Linhof 4x5 but I need to have REALLY long exposure times... (1 hour). I need normal contrast negs for printing...

    One thought was to expose Ilford ortho film with a red filter. Do you think this would allow me to expose for an hour with say, an f16 or f22 ? I guess the red filter for the ortho film will be much stronger than an ND for a panchromatic one...

    On the other hand I can put several ND's one on top of the other, but then I risk vignetting (too many screw-on filters) and they will cost me a fortune to buy...

    I could use an IR filter but I don't know if there will be anything on the film (even if I use a pan film).

    Are there any more ideas ??
    Sorry no ideas.Just curiosity really but what are you taking a photo of? I have never been to your latitude in Winter or this late in Autumn but would have thought that even on cloudy days light intensity would mean that an exposure of an hour would be nearly impossible without gross over exposure even with high ND filters. I have seen a photo of a U.K. motorway with a high ND filter which looked to have no traffic because it was several minutes exposure and the vehicles didn't register but this was only a few minutes not anything like an hour.

    Pentaxuser

  9. #9
    Loose Gravel's Avatar
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    If you are using slow film and can stop down to f/45 or better, then use ND4.0, which is 13 stops. This should get you pretty close if you add the reciprocity. Sure hope your camera doesn't leak.
    Watch for Loose Gravel

  10. #10
    Mongo's Avatar
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    After posting my earlier reply, I thought about this some more. I've had exposures go up to 15 minutes without even trying...bright days, but slow films with very small apertures. Shooting an APO-Nikkor 480mm f/9 at, I believe, f/45 with some bellows extension thrown in, I got into the land of reciprocity failure and was shooting for 15 minutes. (More like 20 minutes to complete the shot, as I would cover the lens whenever a car drove by to avoid any chance of reflections in the pond I was shooting into...almost certainly being too anal, but feeling I'd rather be safe than sorry.) It wouldn't have taken much of an ND filter to push me up to an hour given the reciprocity characteristics of the film I was using.

    My point is, if you can get bellows extension thrown into the equation along with a small aperture and slow film, you might not be far from getting out to an hour for an exposure. Without the bellows extension, it might be worth figuring out which films would give you the greatest reciprocity failure. (I know that Efke films aren't particularly forgiving in this regard.)

    Again, best of luck with your project.
    Dave
    Film is cheap. Opportunities are priceless.

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