Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,900   Posts: 1,584,393   Online: 729
      
Page 1 of 3 123 LastLast
Results 1 to 10 of 23
  1. #1

    Join Date
    Apr 2005
    Location
    San Bernardino, CA
    Shooter
    8x10 Format
    Posts
    749

    "Sharpist" Pinhole Image

    Hello to all,
    I have not stuck my head into this Forum for a long time. My question is: For as close as is possible to a "Perfectly"round hole, I have read that acid etched holes are superior to laser holes. I am also in possesion of some holes that were micro-filed under magnification and are claimed to be superior to laser drilled holes. My goal here may be in conflict with some people's Philosophy. But I want to get the sharpest image that I can, using no lense.. I found a company website that claims superior holes via acid etching. The cost is high, but not discouragingly so.
    Bill

  2. #2
    cliveh's Avatar
    Join Date
    Oct 2010
    Shooter
    35mm RF
    Posts
    3,675
    Images
    344
    An interesting question and I wonder if a scene illuminated by laser light would produce a sharper image in a pinhole camera than one illuminated by diffuse light?

    “The contemplation of things as they are, without error or confusion, without substitution or imposture, is in itself a nobler thing than a whole harvest of invention”

    Francis Bacon

  3. #3
    DWThomas's Avatar
    Join Date
    Jun 2006
    Location
    SE Pennsylvania
    Shooter
    Multi Format
    Posts
    2,277
    Images
    67
    I can believe it could be possible that etched is best. At the microscopic level etching tends to leave a conical hole where I suspect a laser might create a more cylindrical one. But I admit to not knowing much about the state of the art in either technology. Decades back I did some etching of printed circuit boards using photo resist and ferric chloride. There is a tendency for the substrate to etch back under the edge of the resist, but it's a time function so the walls/edges become sloped, thus for a hole it might appear like a knife edge (albeit maybe a dull one!) which is desirable.

    But personally, I try not to obsess quite that much!

  4. #4
    SMBooth's Avatar
    Join Date
    Jun 2008
    Location
    Melbourne, North/West
    Shooter
    Multi Format
    Posts
    1,023
    Images
    7
    Think you need to buy and test. The best way to get the cleanest image from pinhole is bigger formats. Really don't think you will get a visual difference between laser or acid etched.

  5. #5

    Join Date
    Mar 2011
    Shooter
    Med. Format RF
    Posts
    98
    it also might advantageous to think more in contrast than sharp. greater contrast "seems" sharper than a lens that is sharp yet not good contrast. Also I agree, the larger the neg. the better the print. I suggest 16x20 or 20x24 full neg with contact on slow chloride paper. you can still get an order in for ilford for ultra large format sheet sizes S.O. go for it!!!!!!!!!!!!!

  6. #6

    Join Date
    Jun 2008
    Location
    florida
    Shooter
    Medium Format
    Posts
    1,186
    Images
    2
    I profess no knowledge about making the pinhole (I bought an Ilford Titan) but would think that the quality of the hole would be dependent on the materials used and the skill of the technician. With a lens you are generally focusing on a particular spot that would be the most critical point of focus and the depth of field would depend on the length of the lens and f stop. I suppose you could figure out that spot for a pinhole but I don't think most people approach pinhole photography that way.

    http://www.jeffreyglasser.com/

  7. #7
    bvy
    bvy is offline

    Join Date
    Jul 2009
    Location
    Pittsburgh
    Shooter
    Multi Format
    Posts
    998
    Images
    41
    I think it's diminishing returns after a certain point. I did this with pie tin, a sewing needle from my mother-in-law, and clear coat sandpaper. It's 5x7 paper in an oatmeal box.

  8. #8
    Mainecoonmaniac's Avatar
    Join Date
    Dec 2009
    Shooter
    Multi Format
    Posts
    3,193
    Images
    6

    I can't believe it's a pinhole

    Quote Originally Posted by bvy View Post
    I think it's diminishing returns after a certain point. I did this with pie tin, a sewing needle from my mother-in-law, and clear coat sandpaper. It's 5x7 paper in an oatmeal box.
    And you made the lens and camera? Wow. Great job. So how did you calculate the aperture?
    "Photography, like surfing, is an infinite process, a constantly evolving exploration of life."
    Aaron Chang

  9. #9
    Jim Jones's Avatar
    Join Date
    Jan 2006
    Location
    Rural NW Missouri
    Shooter
    4x5 Format
    Posts
    1,863
    Jeffrey is right in suspecting that there is an ideal focal length for each pinhole diameter. This chart shows the effect of pinhole diameter on resolution, both on-axis and up to 60 degrees off-axis. If on-axis resolution is most important, a user constant of maybe 1.5 in PinholeDesigner might give near optimum pinhole diameter. A slightly larger pinhole favors off-axis sharpness. Deviating by 10% from the optimum diameter causes a measureable loss in resolution. For photographers who prefer making photographs over measuring resolution, a pinhole that is larger or smaller than the calculated optimum diameter may provide the most pleasing photographs. Sharpness is academic: photography should be art.
    Attached Thumbnails Attached Thumbnails OffAxis4a.gif  

  10. #10
    RalphLambrecht's Avatar
    Join Date
    Sep 2003
    Location
    Central florida,USA
    Shooter
    Multi Format
    Posts
    6,835
    Images
    1
    lighting has a strong impact on apparent sharpness, whatever that may be, but flat frontal lightingis not as sharp asharsh side lighting.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

Page 1 of 3 123 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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