Seeking Information on Lens Design

Discussion in 'Camera Building, Repairs & Modification' started by PhotoPete, Sep 16, 2005.

  1. PhotoPete

    PhotoPete Member

    Messages:
    320
    Joined:
    Aug 23, 2005
    Location:
    Waltham, MA
    Shooter:
    Multi Format
    Does anyone have any books or websites to recommend on the topic of lens design? Primitive Photography has a few suggestions based on classic lens design, but I am looking from something more comprehensive. Sidney Ray's Applied Photographic Optics is great, but it's very dense and due back to the library before I will have time to absorb all of it. Ideally, I'm looking for something with conscise information about calculating focal length, covering power, deplth of focus, etc. This trial-and-error approach is really getting tiresome.
     
  2. Loose Gravel

    Loose Gravel Member

    Messages:
    921
    Joined:
    Feb 28, 2003
    Location:
    Santa Barbar
    I don't really understand where you are going with this question. Why do you need to calculate focal length? For most, what is marked on the lens is sufficient.

    Covering power: seems to me people look it up on the web, in lens brochures, or try the lens. Some, maybe, can remember all the lens types and coverage.

    Depth of focus is marked on smaller format lenses. There are DOF calculators and there are the same on the web that are Excel based. Here is the Rodenstock model:

    http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=155145&is=REG

    The formulas are in most photo texts.

    There are some freeware ray tracing programs on the web. Mostly used by and designed for the telescope folks.
     
  3. PhotoPete

    PhotoPete Member

    Messages:
    320
    Joined:
    Aug 23, 2005
    Location:
    Waltham, MA
    Shooter:
    Multi Format
    I'm sorry- I was not clear enough in my original post. I am attempting to assemble my own lenses from various individual elements. I am not so ambitious as to grind anyting myself- these are (mostly) coated objectives from other lenses.
     
  4. Dan Fromm

    Dan Fromm Member

    Messages:
    3,979
    Joined:
    Mar 23, 2005
    Shooter:
    Multi Format
    Edmund Industrial Optics' catalog contains recipes that I think are what you need.
     
  5. Donald Qualls

    Donald Qualls Member

    Messages:
    1,845
    Joined:
    Jan 19, 2005
    Location:
    North Caroli
    Shooter:
    Multi Format
    One of the simplest designs is the double achromatic, essentially the same as a Ramsden (I think Ramsden is right; it's either that or Huygenian) eyepiece for a telescope. It's just two achromats of the same specification, facing opposite directions (usually with the convex or more convex face out), spaced according to formula, with the aperture stop midway between the lenses. You can likely buy suitable cemented achromats from Edmund, or you may be able to get them from resources that sell to amateur telescope makers who like to make their own eyepieces. Small telescope objectives should also work well.

    One advantage of symmetric designs like this is that they have no distortion and a flat plane of focus, as a simple consequence of the optics (providing they're spaced correctly). A disadvantage is that they perform best at close to 1:1, and tend to have a small amount of uncorrected spherical aberration and some coma at common photographic magnification factors; this can be largely overcome by using a small aperture, or used to advantage by calling the resulting optic a "portrait lens".
     
  6. Ole

    Ole Moderator Staff Member

    Messages:
    9,284
    Joined:
    Sep 9, 2002
    Location:
    Bergen, Norw
    Shooter:
    Large Format
    There are several books by Rudolf Kingslake which contain what you need.

    And there's a PC program called OSLO which is worth getting - the manual alone is more than worth the price of an evaluation copy.
     
  7. PhotoPete

    PhotoPete Member

    Messages:
    320
    Joined:
    Aug 23, 2005
    Location:
    Waltham, MA
    Shooter:
    Multi Format
    Thanks, all!