Kodak Ektar 100's performance at Long Exposures

Discussion in 'Color: Film, Paper, and Chemistry' started by Shelley-Ann, Dec 14, 2008.

  1. Shelley-Ann

    Shelley-Ann Member

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    Hey

    I'm going to be doing some evening/night shots in Brampton tonight, and I was thinking of using the new Ektar. Does anyone know how it performs with long exposures, and if it should be overexposed at EI 64?

    Thanks.
     
  2. Lee L

    Lee L Member

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    I ran a quick test for reciprocity using a 120 second exposure with a 10 stop ND filter, but it was the end of the roll, so I didn't have room for proper bracketing. My estimated speed loss was about 1.3 stops. That would yield the following adjusted times in seconds.

    metered time -- adjusted time
    1 ----------------- 1.4
    2 ----------------- 2.9
    4 ----------------- 6.3
    8 ----------------- 14.1
    15 ----------------- 29.7
    30 ----------------- 68.4
    60 ----------------- 159.0
    90 ----------------- 261.2
    120 ----------------- 371.7
    240 ----------------- 871.5

    This test is a standard procedure for astrophotography film evaluation.
    I'll see how badly the formatting breaks.

    Oh, there also seems to be a slight cyan shift, but easily recoverable in printing, and without any egregious color crossover.

    Lee
     
    Last edited by a moderator: Dec 14, 2008
  3. Shelley-Ann

    Shelley-Ann Member

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    Thanks, Lee. I'll see what happens tonight.
     
  4. Nightfly

    Nightfly Member

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    How were your results? I'm thinking of testing myself.

    Thanks,
     
  5. Nightfly

    Nightfly Member

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    I finally got around to testing Kodak's new Ektar 100 color negative film.

    My test incorporated a 50mm lens set at f/2.8 and a 30 minute exposure. I shot the darkest part of the sky, directly overhead in the constellation Cygnus. This area has enough hydrogen Alpha to test this films sensitivity to emission nebulae.

    30 minutes is a long time for f/2.8, but this result is in line with other 100 speed films in the reciprocity category.

    This image still shows a little green cast that was present in the original scan. I adjusted green levels to rid most of it, so it is possible to use this film for astrophotography.

    I hope this satisfies any curiosity others may have about this film.

    [​IMG]
     
  6. Lee L

    Lee L Member

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    Interesting test. Thanks for posting. Given the spectral response curve for Ektar 100, the green or cyan shift we've both noticed in long exposures, and the relative brightness of the North American Nebula, Pelican Nebula, and emission nebulae around gamma Cygni, I'd say it looks like the red response is failing more rapidly than the blue and green.

    For f:2.8 and 30 minutes, it doesn't appear that Ektar 100 is an outstanding candidate for astrophotography. Usable, I guess, but not with the best of astrophotography films over the years.

    Lee
     
  7. Nightfly

    Nightfly Member

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    Agreed, it is not the best, but useable at fast f-ratios. I normally shoot medium format at f/4 and 5.6 so this film would not be an option. I won't be stocking it next to my E200, E100S, and Centuria 400.

    Next on the chopping block, Acros 100.........
     
  8. Lee L

    Lee L Member

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    I'll be interested in those results too. Never seen anyone try it, or report on it for astrophotography. Fuji's response curve shows that it drops like a rock above 525-530 nm, so it'll be interesting to see if low reciprocity makes up for poor response in H-alpha. I got some of Freestyle's Legacy Pro 100 (supposed Acros) to try last week. Maybe I'll point a few frames up at night.

    Lee
     
  9. 2F/2F

    2F/2F Member

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    Nice pic, Nightfly. You must have been somewhere reeeealy dark! The only place I have ever seen a sky remotely like that was while camping on my last road trip, in Utah. Not a light anywhere for miles around. You had to look really hard to find any spots of truly black sky.
     
  10. Nightfly

    Nightfly Member

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    I shot it from my home in Maine. I usually shoot with E200.

    More photos at http://www.nightfly.zoomshare.com

    Click on Medium Format Gallery for the best stuff.
     
  11. Nightfly

    Nightfly Member

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    It will be a month or two before I test Acros. I'll be sure to update here. Films are just not tested anymore. Somebody has to do it. I've seen good digital work, but I like my wide-field analog astrophotos, just something about it.

    [​IMG]

    http://www.nightfly.zoomshare.com
     
  12. Tom Kershaw

    Tom Kershaw Subscriber

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    Jim,

    Do you have any "getting started" advice for making these wide-field astro-photographs? Kodak E200 has been discontinued, at least here in the UK.

    Tom.
     
  13. Ektagraphic

    Ektagraphic Member

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    You have done some AMAZING work!
     
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  15. Ektagraphic

    Ektagraphic Member

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    It is so nice that you still preserve such an amazing artform with film and it being to Ektachrome thrills me!
     
  16. Nightfly

    Nightfly Member

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    Yes, I saw your thread on the E200 availability and it raised a red flag here in the states. I spread the word to my fellow film guys about it and I'm glad I stocked up. It seems that E200 in 120 is gone now. I have a freezer full thanks to your notice. It remains in 35mm fairly plentiful for now at least.

    Without E200, or Elite Chrome 200, film astrophotography will take a downturn. There are a few other good films. Fuji Sensia 400 and Provia 400X still perform well.

    Advice? If your looking to use your camera and lenses to image, I suggest looking for a small equatorial mounted telescope to "piggyback" your camera on. Use it to track the stars while your camera's film accumulates starlight. This is what I do. I use 35mm and medium format cameras. I use the 35mm for "fast" imaging and MF for long exposures with finely detailed images.

    I suggest joining a forum like Cloudy nights. Read over the forum threads as many of your questions have been answered there.

    http://www.cloudynights.com/ubbthreads/postlist.php/Cat/0/Board/Film

    I hope this helps. Film astrophotography can be allot of fun. I will suggest first and foremost however that to get good images you should be under a dark sky. I am fortunate to have one here at my home. I sometimes forget that most of the world doesn't.

    Send me a private message and I can discuss further if you would like.
     
  17. Nightfly

    Nightfly Member

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    Thank you. It's nice to have someone recognize film as a valid medium for astrophotography. Most of my contemporaries have gone digital. Some of it good, much of it bad (specific to wide field work) It has gotten better lately, the noise issue is the biggest problem.

    You should see the 6x7 chromes on the light table! I admit that my work posted on the web still doesn't do the original justice. I do not have an expensive scanner. I may send out my best work for really good scans. I'd like that.

    As an artform, film offers a view of the universe unlike any digital image. So with everyone doing digital my images are unique.

    Dark skies and film, got to love it.
     
  18. Ektagraphic

    Ektagraphic Member

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    I just sent you a PM.
     
  19. Tom Kershaw

    Tom Kershaw Subscriber

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    Thanks for your reply. I was thinking initially along the lines of pointing the camera up at the sky and then looking at the results, a very basic start. So if I can still get Elite Chrome 200, it's worth getting some in-stock? The Provia 400X film has the advantage of being available in medium format, but have you tried any colour negative films?

    Tom
     
  20. Nightfly

    Nightfly Member

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    Fuji Superia Pro 800Z is fast, but loses its color performance in a minute or so, however it would be good for begginer imaging due to the short exposures.

    This was an 800Z image taken in April this year. Two exposure mosaic. Each image was done with a Spotmatic II with 50MM F/1.4 SMC TAKUMAR AT F/2. Each exposure was two minutes. Camera was "piggybacked" on an equatorial mounted scope to track while exposing. This image highlights the Sagittarius / Ophiuchus / Scorpius Milky Way low on my south horizon.
    [​IMG]
     
  21. 2F/2F

    2F/2F Member

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    Pretty nifty..."panning" is not something most people would think is done in astrophotography! Great pix!

    What are the chances of getting a nice wide-field shot without having the camera piggybacked on an automatic telescope? Would a 400 film pushed a lot in development do it? Say for example that I was using a 2.8 lens. I'm thinking something like T-Max or Neopan 400.
     
  22. Nightfly

    Nightfly Member

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    A very fast normal or wide angle lens, at least f/2 and fast film will give you a shot at what you describe. Use Provia 400X pushed 1 stop, maybe two. Try a fast b&w film like T-Max. Remember to go to the darkest skies you can find. The Summer Milky Way is due south once its dark. Try 45-90 second exposures at f/2. 60-120 seconds f/2.8. Stars will trail after just 20 seconds or so, but you will get the idea of how it all works.

    Good luck.
     
    Last edited by a moderator: Aug 10, 2009
  23. Lee L

    Lee L Member

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    HP5+ is reported to have slightly less reciprocity failure and much better response to red emission nebulae than TMY-1. Haven't seen reports on TMY-2 for this purpose, or on Neopan 400.

    Both the Kodak and Ilford chromogenic B&W films get good ratings for astrophotography.

    Lee
     
  24. Lee L

    Lee L Member

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    The attached .pdf has some realistic exposure times for unguided astrophotos short enough not to show star trails in 35mm format. Declination is equivalent to earth's latitude projected out into space, so 0-30 declination is everything that would be in a band with +/- 30 degrees north or south of an east-west line directly through the zenith if you're standing on the equator. 90 degrees of declination defines the N and S celestial poles (Polaris and the Southern Cross). Declination is usually shown on star maps, and there are many online that you can use. www.google.com/sky shows two numbers in the lower left of the screen. The second number is declination in degrees, minutes, seconds. You can search there for the constellation you're shooting and find the declination with the cursor.

    As you can see from the attached table, from page 25, Wide-Field Astrophotography, Robert Reeves, as you shoot nearer the celestial equator (0-30 declination) things appear to cover a greater angle more quickly, and so shorter exposures are needed to avoid blur. As you point you camera closer to the north or south celestial poles, the rate of angular motion of the stars is less, and you can make longer exposures without blurring. Shorter focal length lenses can also be open longer than longer focal lengths without apparent star motion blur.

    Lee
     

    Attached Files:

  25. 2F/2F

    2F/2F Member

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    Thanks, Lee.

    I assume that at a given print size, a print from medium format will show less discernible trailing on the print than the same print from 35mm. Is this correct?
     
  26. Lee L

    Lee L Member

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    That's a reasonable assumption to make. You could throw in a magnification factor to relate whatever MF format you're using to 35mm and try that, then modify as needed given your results.

    Akira Fuji (http://www.davidmalin.com/fujii/fujii_index.html) is one of the best known MF astrophotographers. I believe he sometimes uses a Zeiss Softar type filter to make the brighter stars appear larger, more like they do to the naked eye. MF and a good lens can make the main stars in a constellation seem to get lost in the "background" stars.

    Lee