Lower than f.95

Discussion in 'Open Discussion' started by LegacyLens, Jun 17, 2012.

  1. LegacyLens

    LegacyLens Mu-43 Regular

    99
    Apr 25, 2012
    If you go to f.01 assuming it is mathematically possible would you have ANY dof? Or just a very soft crappy image. (for the first question assume that it is very sharp.)

    auto will destroy us all
     
  2. jyc860923

    jyc860923 Mu-43 Hall of Famer Subscribing Member

    Feb 28, 2012
    Shenyang, China
    贾一川
    a little off the topic, I have read both sides comments and it kinda makes me doubt if the 25 0.95 really beats the 25 1.4 in sharpness under the same aperture.
     
  3. nickthetasmaniac

    nickthetasmaniac Mu-43 All-Pro

    Jan 11, 2011
    Curious why you thought this comment should be posted in this thread?
     
  4. CUB

    CUB Mu-43 Veteran

    275
    Apr 19, 2012

    The aperture limit for a lens is about f/0.7. You can use the usual DOF equations to see how much (or how little) depth of field that aperture gives.
     
  5. Promit

    Promit Mu-43 All-Pro

    Jun 6, 2011
    Baltimore, MD
    Promit Roy
    • Like Like x 1
  6. nickthetasmaniac

    nickthetasmaniac Mu-43 All-Pro

    Jan 11, 2011
    Why is that? I'm genuinely curious
     
  7. Justified_Sinner

    Justified_Sinner Mu-43 Regular

    193
    Feb 11, 2010
    Scotland, UK
    Dauvit Alexander
    Thanks for starting this thread. I was thinking about this all afternoon after reading the articles on Stanley Kubrick's "Barry Lyndon" in this thread earlier:

    https://www.mu-43.com/f35/stanley-kubrick-photographer-27934/

    That list on Wikipedia has me wanting to see some of these bizarre lenses, such as the f0.5:

    USSRPhoto.com - Russian / Soviet Cameras Wiki Catalog - World's fastest lens

    There are some photographs taken with the Rayxar 50mm f0.7 on an EP-1 here:

    Hand mit Rayxar 50mm f0,75 | Flickr - Photo Sharing!

    As the original post suggested: mush!
     
  8. CUB

    CUB Mu-43 Veteran

    275
    Apr 19, 2012

    I wish I could remember. A university professor who specialised in optics told me some years ago but my memory is like a sieve. :rolleyes:

    But I have seen the f/0.7 quoted in magazine articles quite a few times since.
     
  9. Conrad

    Conrad Mu-43 Veteran

    The simple answer: yes.

    But there are some practical limits. Lenses become increasingly larger for smaller f-numbers, especially when they need to be used at different object distances. The reason is that the lens diameter is inversely proportional to the f-number. The second reason is that the lower the f-number, the more difficult it is to control the aberrations, and even more glass (extra elements, special glass) is needed for that.

    For photo/film purposes, faster than f/0.95 is an extreme rarity. For fixed distance applications (like some technical imaging), f/0.7 does occur. Two imaging areas, however, excel in low f-numbers: microscopy and IC lithography. For both, equipment is available with f-numbers as low as 0.18 to 0.20. But these are highly specialized lenses, with almost fixed magnification and working distance (measured in microns) and typical dof of a few hundred nanometers. That is a thousand times thinner than paper.
     
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  10. LegacyLens

    LegacyLens Mu-43 Regular

    99
    Apr 25, 2012
    Now I am wondering if microscope lenses can be mounted on m43 thanks lol
     
  11. Promit

    Promit Mu-43 All-Pro

    Jun 6, 2011
    Baltimore, MD
    Promit Roy