Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,290   Posts: 1,535,401   Online: 766
      
Page 1 of 2 12 LastLast
Results 1 to 10 of 17
  1. #1
    yeknom02's Avatar
    Join Date
    Mar 2010
    Location
    State College, PA, United States
    Shooter
    Multi Format
    Posts
    308
    Images
    5

    Questions on my first pinhole - 8x10

    Hi guys, I was thinking of trying to build an 8x10 pinhole camera this spring. Probably made out of wood, and something with a fairly "normal" focal length, to be a general-purpose large-format camera that's really easy to work with.

    1) I want to shoot 8x10 paper negatives. Should I plan on making a camera based on an 8x10 film holder, or will paper not fit in a holder? If not, what would be an easy way to load the camera?

    2) I've heard that paper negatives need low contrast. Can I put an Ilford 0-grade filter behind the lens to help with this?

    3) How accurate does the hole-to-film-plane distance need to be?

    4) Any tips coming to mind from past pinhole-building experience that I can't afford to learn by trial and error?

    I'm going to continue reading up on the subject... Thanks for any pointers!
    "When the going gets weird, the weird turn pro." - HST
    My Flickr Gallery

  2. #2

    Join Date
    Apr 2004
    Location
    Montgomery, Il/USA
    Shooter
    Multi Format
    Posts
    5,042
    People have just used double faced tape, installed grooves as they built their camera, anything that you can figure out. Focal length can be anyplace you want, There is an optimum diameter/focal length that can be calculated. There's bunches of information at f295.org
    Heavily sedated for your protection.

  3. #3
    David William White's Avatar
    Join Date
    Jun 2007
    Location
    Hamilton, Canada
    Shooter
    Multi Format
    Posts
    1,182
    Blog Entries
    1
    Images
    32
    Super!

    1. Film holders really help, if you have some. I fit mine against weatherstripping to make a light-tight seal. You can use the darkslide on the holder to 'strip test' (ie. bracket) your first few test exposures. You will need to give the paper a small trim to fit the holders, but that's no biggie.

    2. Yes, or any old yellow filter, but likely in front of the pinhole -- just to protect it from the elements. Alternately, you can shoot on overcast days when the contrast is lower, or you can pre-flash the paper a wee bit. Softer developers (diluted Selectol-Soft) are also an option.

    3. For best results, the pinhole should be sized according to the so-called focal length. So for a 10" distance, you'll need a pinhole in the neighbourhood of 0.6mm.

    4. If you are proceeding with a 'normal' focal length, you might want to fit a wire frame or suchlike to aim the beast.

    Have fun!
    Considerably AWOL at the present time...

    Archive/Blog: http://davidwilliamwhite.blogspot.com

  4. #4
    Jim Jones's Avatar
    Join Date
    Jan 2006
    Location
    Rural NW Missouri
    Shooter
    4x5 Format
    Posts
    1,803
    Quote Originally Posted by yeknom02 View Post
    . . . 2) I've heard that paper negatives need low contrast. Can I put an Ilford 0-grade filter behind the lens to help with this?

    3) How accurate does the hole-to-film-plane distance need to be?
    2) You can also reduce contrast by altering the developer and development time. Solarol developer gives low contrast, but reduces the effective speed of the paper.

    3) not at all precise. The recommendations of optimum focal length for a specific pinhole diameter vary over a wide range. I prefer Pinhole Designer http://www.pinhole.cz/en/pinholedesigner/ with a constant of 1.5. Mr. Pinhole is another popular calculator.

    A site with much information is http://home.online.no/~gjon/pinhole.htm. The definitive reference book is Eric Renner's Pinhole Photography.. The definitive reference book is Eric Renner's Pinhole Photography.

  5. #5
    yeknom02's Avatar
    Join Date
    Mar 2010
    Location
    State College, PA, United States
    Shooter
    Multi Format
    Posts
    308
    Images
    5
    David, what do you mean by a wire frame to aim the camera?

    Is a 0.6mm pinhole easily manufactured with a needle or am I going to have to turn to precision-manufactured pinholes?
    "When the going gets weird, the weird turn pro." - HST
    My Flickr Gallery

  6. #6
    yeknom02's Avatar
    Join Date
    Mar 2010
    Location
    State College, PA, United States
    Shooter
    Multi Format
    Posts
    308
    Images
    5
    Jim, thanks for your recommendations. Eric Renner's Pinhole Photography arrived today and I'm currently looking through it.
    "When the going gets weird, the weird turn pro." - HST
    My Flickr Gallery

  7. #7
    David William White's Avatar
    Join Date
    Jun 2007
    Location
    Hamilton, Canada
    Shooter
    Multi Format
    Posts
    1,182
    Blog Entries
    1
    Images
    32
    Quote Originally Posted by yeknom02 View Post
    David, what do you mean by a wire frame to aim the camera?
    If you look at a Speed Graphic (& similar), they have a pull up wire frame on the front standard that's used with a sight on the rear standard to aim the camera, and a crosshairs on the front wire frame will give you both centre and frame coverage. Similar to 'sport finders' on TLR's and such. I only mention because most pinhole cameras are ultra wide angle, where aiming isn't so much of a concern. If you're going 'normal', you might wish to rig a finder of this sort.

    (Another option is to have a simple lens on the front, some glassine or vellum paper for a ground glass, line everything up, then replace the lens with your pinhole and the glassine with your paper holder.)

    Quote Originally Posted by yeknom02 View Post
    Is a 0.6mm pinhole easily manufactured with a needle or am I going to have to turn to precision-manufactured pinholes?
    Depends on how much sharpness and resolution to want, your artistic vision, etc. You can poke holes in tinfoil with a #8 needle, examine each in your enlarger to find the cleanest one, or just be a lot more fast and loose. Slits are fun too.

    D.
    Considerably AWOL at the present time...

    Archive/Blog: http://davidwilliamwhite.blogspot.com

  8. #8
    aaronmichael's Avatar
    Join Date
    Nov 2010
    Location
    Long Beach, CA
    Shooter
    Large Format
    Posts
    242
    Unless you want vignetting, you want to make sure that the focal length projects a big enough image to fill up your entire 8x10 negative. Longer the focal length = larger the image. I made an 8x10 pinhole camera a couple months ago and just tape the paper to the back. This was because I don't have the skills to make something that could take a film holder - haha. I third or fourth what everyone else says about the yellow filter, seems to work well for me. Just be sure to add a stop or so of exposure time to compensate. Also move the yellow filter around during the exposure so your image doesn't have dust specs on it that are on the filter. I use aluminum from soda cans to make my pinholes. Cut the can up then use an orbital sander to shave it down even more thin. Poke a small hole through with a sewing needle, sand down the burr on the other side. Not to get into the topic of scanning but if you want to be real accurate, you can scan and measure the diameter with a photo program. Also, one of the things that helped me out the most was an exposure formula that another user on here gave me. I'd give credit if I could remember his user name. The formula is:

    Tc = Tm (Fc/16)^2

    Where Tc = Correct exposure time, Tm = Exposure time metered at f/16, and Fc = Focal ratio (equivalent to the aperture number of your pinhole). And then of course you need to add time on top of that to compensate for papers slow ISO. I attached a picture of my 8x10 pinhole camera and a recent photo I took with it.



    http://www.flickr.com/photos/aaronmichael/5533307599/

  9. #9
    bvy
    bvy is offline

    Join Date
    Jul 2009
    Location
    Pittsburgh
    Shooter
    Multi Format
    Posts
    847
    Images
    36
    I second Renner, and I'll add Mr. Pinhole as an invaluable resource -- especially as it relates to finding an optimum pinhole diameter for a given "focal length" (or vice versa):
    http://www.mrpinhole.com/

  10. #10
    Jim Jones's Avatar
    Join Date
    Jan 2006
    Location
    Rural NW Missouri
    Shooter
    4x5 Format
    Posts
    1,803
    Quote Originally Posted by yeknom02 View Post
    . . . Is a 0.6mm pinhole easily manufactured with a needle or am I going to have to turn to precision-manufactured pinholes?
    Making pinholes isn't difficult. I recommend .002" brass shim stock, available in many hardware or perhaps auto supply stores. Aluminum is popular, but isn't as nice to work with. I've also used very thin stainless steel where small precise pinholes were needed, but it is difficult to work with. Measuring the size can be more difficult for some. Eric Renner's book gives several methods for this. For a perfectionist, pinhole diameter should be within five or ten percent of the design size. Pinhole photography is quite forgiving of imperfection. We do better when we concentrate on making the best possible photograph with whatever camera we use than when we merely concentrate on making or buying the best possible camera.

Page 1 of 2 12 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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