aperture question - for you technical wizards

Discussion in 'Beyond the Basics' started by thebeginning, Jul 21, 2005.

  1. thebeginning

    thebeginning TPF Noob!

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    i remember seeing somewhere a lens that had a large set aperture (1.8) and somehow claimed to have such a great DoF that it did not need focusing. so basically it was a lens that could let in as much light as a 1.8 lens, but it's DoF was similar to a lens set at f22 or f32. is that possible? it wasnt an incredibly wide lens, i think it was around 30mm, so that wouldnt explain it. so is there any way that can somehow be done?
     
  2. wharrison

    wharrison TPF Noob!

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    I sinerely doubt as to whether such a lens exists, especially one with all of the qualities you're giving it.

    However, there are (historically) lenses with fixed aperture settings. They are known as "Waterhouse stops". Some information with regard to these types of apertures follows.
    1. A system of interchangeable fixed-size aperture plates.

    In the mid to late 1800s camera lenses did not have adjustable iris-type aperture diaphragms as they do today. Instead they either were used wide open or else employed a system of interchangeable black metal plates. These plates, which were inserted into a slot on the side of the lens barrel, had holes drilled into them. The photographer would adjust the lens aperture by swapping out one plate for another with a different size of hole. These plates were named Waterhouse stops, apparently after the inventor who came up with the system in 1853 or 1858 or thereabouts.

    Entry last updated 2002-04-18. Term 1285 of 1472.


    2. A link to historic lenses with "waterhouse stops", which might be of some interest.


    http://www.boxcameras.com/2brasslenses.html


    3. In my brief explorations, I did find something called "lensbabies" which might be of some interest. Here's a link.


    http://www.lensbabies.com/index.php?r=GSBellows


    Hope this is useful!


    Bill
     
  3. tr0gd0o0r

    tr0gd0o0r TPF Noob!

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    without any kind of research or anything along those lines, i would expect that the description you give describes both extremes of the lens. I.e. it has 1.8 AND and f32 (or around that) it's so sharp you don't have to focus
     
  4. ksmattfish

    ksmattfish Now 100% DC - not as cool as I once was, but still

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    Possibly it was fix focused on it's hyperfocal distance. Hyperfocal distance is the closest focus point to the camera where infinity is still included in the DOF. As long as infinity, which occurs around 30' with a 50mm lens, is in the DOF, then everything from the near DOF to infinity is in focus. With f/2 this might mean everything past 25'. With f/22 this would mean everything past 6' or 7'. But if your subject is consistantly 25' from the camera (like shooting from an airplane) then it's not going to matter if you have the camera set to f/2 or f/22 (disregarding possible lens design problems).
     
  5. Hertz van Rental

    Hertz van Rental TPF Noob!

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    I have two lenses of this type. One with interchangeable pierced blades and one with a rotating disk with different sized apertures.
    Both are from around 1860.
     

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