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  1. #1
    Perry Way's Avatar
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    Ektrachrome Reciprocity for Pinhole purposes

    Hello All,

    I recently bought a box of Ektrachrome 100G in 4x5 and specifically looked for reciprocity information before shooting $35 worth of film in 10 easy shots.

    As per instructions found inside the box of film I set about last weekend to shoot all 10 shots with a little feather in my cap. I intuited that the information you can read like on this page here: KODAK Reciprocity Info is information not for pinholers but for normal photography. So without so much as a good realistic guide for reciprocity I do what I normally do and that is examine all the reciprocity figures for all the films I have information on, and apply a best average using whatever information I can shoot from the hip. So basically I treated Ektachrome like it was an average of TMAX 100 and FP4 reciprocity exposure figures.

    After using my shoot from the hip reciprocity exposure information, if anything the shots should have come out overexposed, but instead they came out underexposed. This is the third time (using three different eras of Ektrachrome) for this mistake for me. Everything is underexposed. Not by much but by enough that makes it difficult to render anything with the scans. And I spent $10 a scan on these so that's $108 down the drain almost. Again. I've repeated this enough times to know that the reciprocity figures supplied by Kodak are just plain wrong for pinholers. I think there's got to be a different way to calculate things for pinhole versus normal lens-photography where you have a lot of light to work with. Anyone with some hints or advice based on experience?
    I love the wilderness and I love my trail cameras, all Fuji's! :) GA645, GW690 III, and the X100 which I think is the best trail camera ever invented (to date).

  2. #2
    DWThomas's Avatar
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    Dunno, the only color transparency film I've shot with pinhole was Fujichrome T64 with an 85B filter taped over the front. An equivalent exposure only about 20% longer than a test shot with a lens (same scene, same camera) produced a good exposure match. The info available seems to be a little sketchy, and the tungsten films are apparently optimized for longer exposures, which worked in my favor. With multiple failures, I'm inclined to wonder if your calculated f-stop might be off -- it wouldn't take much of an error in that pinhole diameter measurement to throw things off quite a bit. In the instance I described, I bracketed several exposures about a stop either way. I fear testing is about the only reliable way. My approach would be to run a roll with some bracketed test shots and skip any expensive scanning until you see what you get.

    The other hazard with color, of course, is that the different layers may respond differently as you get far away from the optimized useful range. I notice that Kodak sheet said something about a small color compensation filter at long exposures.

  3. #3

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    First, don't have your film scanned until you have seen it, unless you enjoy potentially throwing a lot of money down the toilet.

    Ektachrome is nowhere near as good at maintaining reciprocity during long exposures as is Fujichrome.

    Of course the shots are underexposed. That is what reciprocity failure does, so you would expect that, not overexposure. You did not adjust enough. You need longer exposures.....and/or Fujichrome. No film is designed to be optimized at the effective f stops and exposure times used with pinholes. It is especially hard to get it to work in night shots, as film will not be exposed at all below a certain amount of light, no matter how long the exposure is. You simply need to experiment more. Make sure your effective f stop is properly calculated, first of all.
    2F/2F

    "Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."

    - Rob Tyner (1944 - 1991)

  4. #4
    Perry Way's Avatar
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    Now that I got home, I am seeing that these are not as bad as I initially thought. I think perhaps the monitor I have at work is darker than this one at home. Plus I think that there has to be a video card capability difference because they look better than I thought. Having said that, they are clearly slightly underexposed. I did not intend for navy blue skies... haha. Vivid color. gotta love it? I dunno... anyway...

    Quote Originally Posted by 2F/2F View Post
    Ektachrome is nowhere near as good at maintaining reciprocity during long exposures as is Fujichrome.
    Dude, I am in total agreement with you on this. I thought at first in my mind I did not want to touch Fujicolor anything as I am not fond of the negative film at all. But I had a box here, and shot it and had a problem with overexposure on darn near most of the shots because most of the shots were full daylight and thus the reciprocity effect is minimized. Clearly I have to tidy up all my allowances. But at this point I am close to labeling where the real reciprocity should be on Astia. I love Astia. Love it all the way. It is probably the best 4x5 film on the market if you are going to scan. Anyway, Astia is only slightly skewed on the higher speeds (I estimate 1.25x to 1.5x) and gets closer to the curve of TMax 100 figures when f22 is slower than 1/15 second but not quite as slow as TMax 100. I have not tested for any scenario where f22 is slower than 1/4 second as far as I can remember.

    Quote Originally Posted by 2F/2F View Post
    Make sure your effective f stop is properly calculated, first of all.
    Yes, that is under wraps. Got the accurate figures from Zero Image and used software program to plug in the parameters of the camera to derive my list of exposure variants.
    I love the wilderness and I love my trail cameras, all Fuji's! :) GA645, GW690 III, and the X100 which I think is the best trail camera ever invented (to date).

  5. #5
    Perry Way's Avatar
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    Quote Originally Posted by DWThomas View Post
    Dunno, the only color transparency film I've shot with pinhole was Fujichrome T64 with an 85B filter taped over the front. An equivalent exposure only about 20% longer than a test shot with a lens (same scene, same camera) produced a good exposure match.
    Okay, this lines up pretty much with my experience too. To a degree though, because it does get slower exponentially the dimmer the light.


    Quote Originally Posted by DWThomas View Post
    The info available seems to be a little sketchy, and the tungsten films are apparently optimized for longer exposures, which worked in my favor.
    Very good, then I will expose these 20 I have in the freezer in readyloads next and save the daylight film for my Cambo this next time around. I'm really thinking of ending the affair with Ektachrome soon as I am out of my stock which is only 30 sheets. I'm going back to Astia.

    Quote Originally Posted by DWThomas View Post
    With multiple failures, I'm inclined to wonder if your calculated f-stop might be off -- it wouldn't take much of an error in that pinhole diameter measurement to throw things off quite a bit.
    Well, I used the specifications provided by Zero Image on this camera. I shot all my past Ektachrome on another pinhole camera that I found out to be really umm.. sub-par. I am confident that my calculations are correct because I am getting better results now than ever before. However, understanding the incremental nature of adjusting for exposure variations can become a rather expensive proposition these days which is why I am asking for someone to share what worked for them so I can cut down on my loss of $'s at a time when I am ramping up to quit the day job and go travel nonstop for photographic purposes. Anyway, I am inclined at this point to believe that Ektachrome is slightly unpredictable in general from one emulsion to another perhaps, and, that the curve may be more of a set of stairs rather than an incline.
    I love the wilderness and I love my trail cameras, all Fuji's! :) GA645, GW690 III, and the X100 which I think is the best trail camera ever invented (to date).

  6. #6
    Perry Way's Avatar
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    Okay, after hours of trying to reduce the size of one of these scans but crashing the editor a bunch of times from running out of memory, I located a utility program to resize them for me in batch mode, and it actually works. I'll be buying this program. Anyway, started with 4800 dpi scans and now used this program to reduce the size down to where Paintshop Pro can handle it. The program puts a stupid watermark on it but at least I get to see what happens when you reduce the size of the image. It actually looks pretty okay. In fact, I think if I were to had shot this in 75mm instead of 50mm I wouldn't have gotten the vignetting which made me have a panic attack when I first viewed these files. So, here I'm uploading a web-sized reduction so it will fit here. What do you think? 1/2 stop underexposed? I think I'm fairly close... but not right on.
    Attached Thumbnails Attached Thumbnails 20.03-20-2010.Way-037a.jpg  
    I love the wilderness and I love my trail cameras, all Fuji's! :) GA645, GW690 III, and the X100 which I think is the best trail camera ever invented (to date).

  7. #7
    Athiril's Avatar
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    You really cant beat Astia when it comes to colour for just about anything

  8. #8
    Lee L's Avatar
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    The page with the data that my earlier post refers to has been taken down. But here is a post about Ektachrome 100 films in the era of 100G, and some numbers for calculating reciprocity that should get you a lot closer. The numbers (Schwarzschild exponents) were derived from standard astrophotography tests that test for the amount of reciprocity failure at 128 seconds of exposure time, and are typically good within about 1/3 stop. 100G was one of the Ektachromes with the least reciprocity failure, about equivalent to the best of the Fuji E6 films regarding reciprocity failure.

    http://www.apug.org/forums/forum44/2...tml#post242558

    Lee

  9. #9
    DWThomas's Avatar
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    Underexposed or not, that's a neat shot. I'd bet another half stop should do it.

    That data sheet on the 100G strikes me as a bit odd. They say no compensation necessary for exposures up to 10 seconds. Then they mention some color correction at 120 seconds, but unless I missed something (it's happened!) there doesn't appear to be any exposure recommendation for the range from 10 to 120 seconds. Surely it would likely need more than color correction.

    There have been some discussions on this forum sometime back about reciprocity failure in B&W films that seemed to suggest the makers' indicated numbers were over compensated, and that maybe the manufacturers are running with ancient numbers. That could be another reason to do your own tests. I'm pretty convinced the exposure numbers from Pinhole Designer for Delta 100 were overcooked, based on my limited experience.

  10. #10
    Ektagraphic's Avatar
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    With my experience, Ektachrome for me is the only film I know sucessfully works at night for me so far. I have gone up to 30 seconds with no exposure compensation or filters and I had very very good results!!
    Helping to save analog photography one exposure at a time

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