are non digital lenses better for digital slrs?

Discussion in 'Digital Photography' started by Luis ORTEGA, May 23, 2004.

  1. Luis ORTEGA

    Luis ORTEGA Guest

    My understanding is that since a digital slr sensor is smaller than the area
    of a 35mm negative on some digital slrs (say the nikon d70), then using a
    lens designed for a film slr would tend to produce a better image since most
    lenses are best in the central part of their image area and that is the part
    of the image that would be captured on the digital sensor.
    does this theory make sense, or is it correct?
     
    Luis ORTEGA, May 23, 2004
    #1
    1. Advertisements

  2. Luis ORTEGA

    bmoag Guest

    Lenses that are soft at the corners or tend to vignette at wider apertures
    will seem better because of the smaller sensor. But a lens that is a dog in
    terms of sharpness and contrast, for example every 28-200/300 zoom by every
    manufacturer, is still going to be an unsharp and low contrast dog with
    better looking corners.
     
    bmoag, May 23, 2004
    #2
    1. Advertisements

  3. Luis ORTEGA

    Mxsmanic Guest

    An article this month in the French camera magazine _Chasseur d'Images_
    appears to support this. Since the 35mm lenses must cover a larger
    area, the small area used by most digital sensors does not extend into
    the margins of the image area where lens defects are most obvious. In
    side-by-side tests of several "digital" and "non-digital" lenses, the
    non-digital lenses did better overall.

    Of course, this has nothing really to do with whether a lens is
    "digital" or not; it's simply a consequence of designing one lens to
    cover a larger area and then using only the central portion of the image
    field. For full-frame DSLRs, this question is moot, as their image
    areas are the same as those of 35mm film cameras.
     
    Mxsmanic, May 23, 2004
    #3
  4. Luis ORTEGA

    Old Nick Guest

    On Sun, 23 May 2004 00:51:00 +0100, "Luis ORTEGA"
    <> vaguely proposed a theory
    .......and in reply I say!:
    remove ns from my header address to reply via email

    I am masking elsewhere about this to refresh my brain.

    But IIRC, the sensor "sees' the whole lens no matter what size it is.
    So edgew softness would still be an issue. In fact as one other poster
    said, because of the smaller sensor, a lot of "good" 35mm camera
    lenses will not come up to scratch.

    One possible advantage of using a larger lens is that you can stop the
    lens way down and still have a lot of light coming in, compared to the
    smaller "digital" lenses. _This_ would get rid of edge softness, as
    the iris provides greater depth of field and starts to occlude the
    lens edges. (??? again I am thinking about this. rusty.)
    *******************************************************

    Sometimes in a workplace you find snot on the wall of
    the toilet cubicles. You feel "What sort of twisted
    child would do this?"....the internet seems full of
    them. It's very sad
     
    Old Nick, May 24, 2004
    #4
  5. Luis ORTEGA

    Lionel Guest

    No, that's not correct. Any sensor that is smaller than a 35mm frame
    only sees the central portion. And yes, this does have advantages with
    35mm-system lenses that suffer from edge softness / distortion /
    vignetting.
     
    Lionel, May 24, 2004
    #5
  6. Luis ORTEGA

    Bill Funk Guest

    The lens (in the case of 35mm cameras) puts an image on the focal
    plane that is large enough to cover the 35mm film frame. It has to.
    In DSLRs using lenses for 35mm cameras, the lenses still put that same
    size image on the focal plane, but (unless it's a 'full size' sensor)
    the sensor is smaller than a 35mm frame, so some of that image from
    the lens falls outside of the sensor.
    You can go here; this page shows a representation of the different
    sizes of sensors, and how they compare to a 35mm film frame:
    http://www.dpreview.com/reviews/olympuse1/

    Using the term "large(r) lens" is confusing; does "larger" refer to
    focal length, f-stop, 4X5 vs 35mm?
     
    Bill Funk, May 24, 2004
    #6
  7. Luis ORTEGA

    Old Nick Guest

    On Mon, 24 May 2004 16:49:14 +1000, Lionel <> vaguely
    proposed a theory
    .......and in reply I say!:
    remove ns from my header address to reply via email

    Yeah. When I thought about it, that's why you get greater
    magnification from a smaller sensor and a given lens.

    Sorry. Brain fart.

    *******************************************************

    Sometimes in a workplace you find snot on the wall of
    the toilet cubicles. You feel "What sort of twisted
    child would do this?"....the internet seems full of
    them. It's very sad
     
    Old Nick, May 25, 2004
    #7
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.