Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 69,989   Posts: 1,524,087   Online: 1135
      
Page 2 of 4 FirstFirst 1234 LastLast
Results 11 to 20 of 33
  1. #11
    Jim Jones's Avatar
    Join Date
    Jan 2006
    Location
    Rural NW Missouri
    Shooter
    4x5 Format
    Posts
    1,783
    Here are several approaches to increasing shutter speeds in lensless photography. They all involve a reduction in image quality.

    1. Reduce the film size.

    2. Reduce focal length.

    3. Use fast film: ISO 3200 film can be pushed to even higher speeds with a loss of shadow detail.

    4. Use flash.

    5. Use zone plates.

    Pinhole cameras have been used for high speed photography. 70 years ago General Electric built a high speed pinhole camera to record the progression of electrical arcs at 120,000 frames/second (page 42-43, Photo Technique, October 1939). However, this special project has no application in conventional photography.
    Last edited by Jim Jones; 04-17-2008 at 10:22 AM. Click to view previous post history. Reason: additional information

  2. #12
    Christopher Walrath's Avatar
    Join Date
    Dec 2005
    Location
    Milton, DE, USA
    Shooter
    4x5 Format
    Posts
    6,980
    Blog Entries
    29
    Images
    19
    I switched to Efke25 in my 35mm matchbox pinhole cameras which, at f/90, put about EV15-EV15.5 at about 1 second. I use TMX in my 6x6 homemade pinhole for an EV16 at one second (f/256).
    Thank you.
    CWalrath
    APUG BLIND PRINT EXCHANGE
    DE Darkroom

    "Wubba, wubba, wubba. Bing, bang, bong. Yuck, yuck, yuck and a fiddle-dee-dee." - The Yeti

  3. #13

    Join Date
    May 2006
    Shooter
    Medium Format
    Posts
    775
    Chris,

    How do you like the Efke 25 for pinhole? I have a couple rolls for testing in my 645, thought I would test both lens and pinhole on that platform. Also bought some Efke 50 to shoot along side the 25. Planned on having it DR5 processed for positives.

  4. #14

    Join Date
    Jan 2005
    Location
    Austin, TX
    Shooter
    4x5 Format
    Posts
    46

    Hyperfocal Camera?

    If you're willing to accept a little bit of field curvature, a hyperfocal camera might be a better idea (you can find more information on these at http://pinhole.stanford.edu/hyper.htm). The idea (consistent with Ray's suggestion) is to get a simple positive lens element and stick it behind a slightly enlarged pinhole. You can get positive lenses in specific focal lengths from Anchor Optics for between $5-$10. I took the attached photos (on TMX) using a 50mm 4x5 hyperfocal camera that I built using an element from a trashed lens. The pinhole on this camera is about .45mm, creating an f-number of about f/107. With such a camera, your desired shutter speed should be possible (e.g., by pushing 400 film two stops on a sunny day).
    Attached Thumbnails Attached Thumbnails crop0018_smaller.jpg   hyperpinhole_image1.jpg  
    Melchi M. Michel

  5. #15
    Murray@uptowngallery's Avatar
    Join Date
    Sep 2003
    Location
    Holland, MI
    Shooter
    Pinhole
    Posts
    1,028
    That's a good compromise.

    Where'd he go?
    Murray

  6. #16

    Join Date
    Feb 2008
    Location
    Sydney, Australia
    Shooter
    35mm
    Posts
    34
    Quote Originally Posted by Murray@uptowngallery View Post
    Where'd he go?
    I'm still here. I have been spending a bit of time trying to take this thread in before I replied and demonstrated my total novice apprach.

    I understand what everyone has said about not getting a great exposure with my suggested method and am trying to read up on your comprimises (which I thank you all for giving me! )

    Firstly I should explain what I want to do and why...

    I've always been told to shoot what I love and what inspires me.

    My #1 passion in life is mountain biking, (followed closely by music and photography) so I want to concentrate on Mountain Biking as a subject.
    Telling a story of not only the personalities, but also the reason those people compete which is the traveling, the social life it provides, and the action and adrenelene etc.

    This last point is the reason for this post. I really want to capture the action utilising something I'm also interested in, lensless photography.

    Most other aspects of this sport (the places it takes us, the social life it provides and the personalities it involves) can be covered by relativelly low shutter speeds.

    I have an idea for making a pinhole camera out of a full face mountain bike helmet (similar to a motorcycle helmet) so a smaller format size would suit this application.
    The pinhole would be inside the helmet and the framing of the image would try to replicate the cyclist's view. i.e. the image would be framed by the opening at the front of a helmet.
    This would be used to shoot the courses we compete at from the riders perspective. Some of which is the most beautiful scenery in Australian.

    While taking action images through pinhole, is it possible to take multiple (sequenced) images of a single rider descending the course (all taken from the same position) and will the rider become visible in multiple positions across the image?
    What I mean is, if the appropriate shutter speed is 8 seconds, can I take 16 x 0.5 sec exposures, and would the rider become visible in the image. I'm guessing not.

    Hope this explains my intentions...
    And thanks again for all the advise, I'll spend some time reading up on your sugestions and try to take it all in!

  7. #17

    Join Date
    Dec 2005
    Location
    Eastern, Australia
    Shooter
    Multi Format
    Posts
    1,020
    Images
    55
    g'day Nathan

    there are probably easier/faster/more effective ways to achieve what you have in mind

    great ideas, but what will aspects such as using a helmet camera add to the final images?

    why do you need to do the activity whilst you photograph it?

    your multiple exposure idea, any object within the image area that does not move will be recorded and exposed correctly, anything that moves constantly will record a 16th less/thinner than normal/correct

    Ray

  8. #18

    Join Date
    Feb 2008
    Location
    Sydney, Australia
    Shooter
    35mm
    Posts
    34
    Quote Originally Posted by Ray Heath View Post
    great ideas, but what will aspects such as using a helmet camera add to the final images?

    why do you need to do the activity whilst you photograph it?
    I'm not talking about photographing whilst doing. I mean I want to frame the image to give the illusion that the viewer is seeing what a rider would be - From the inside of a full face helmet.
    The camera would be set up on a stationary tripod and mounted inside a full face helmet.
    Blured movement by moving the camera forward whilst exposing would definatelly add to the sense of speed, but I dont think I could come up with a practicle way of achieving this other than setting up a rail system.

    Once I have a camera made, I might do some experiments to this effect though!

    Quote Originally Posted by Ray Heath View Post
    your multiple exposure idea, any object within the image area that does not move will be recorded and exposed correctly, anything that moves constantly will record a 16th less/thinner than normal/correct

    Ray
    Yep, thats what I thought...
    Last edited by NathanBell; 04-21-2008 at 12:27 AM. Click to view previous post history.

  9. #19
    Jim Jones's Avatar
    Join Date
    Jan 2006
    Location
    Rural NW Missouri
    Shooter
    4x5 Format
    Posts
    1,783
    A subject recorded in several exposures as it moves across a stationary background will appear like a transparent ghost, if at all. When the subject is brightly illuminated and the background is quite dark it works somewhat better. To best combine your interest in mountain biking, music, and photography you might bike to a scenic destination, set up a traditional pinhole camera, and time the exposure with music as Leopold Mannes and Leopold Godowsky did in the darkroom while they were doing the research that led to Kodachrome.

  10. #20
    Murray@uptowngallery's Avatar
    Join Date
    Sep 2003
    Location
    Holland, MI
    Shooter
    Pinhole
    Posts
    1,028
    Two Leopold's on the same project. That's synergy. Maybe that's why such things aren't discovered every day.

    Nathan - you need a second Nathan on this project.
    Murray

Page 2 of 4 FirstFirst 1234 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin