Resolution with APS sensor vs. full-frame

Discussion in 'Digital Photography' started by Paul Flackett, Sep 25, 2005.

  1. Did anybody ever compare extreme wide angle lenses (say 100 degrees or
    more) on different formats?

    According to your theory, it should be easier to build a high resolution
    wide angles for medium format than for 35mm, and large format should again
    be easier.

    However, it is not really common knowledge among photographers that you
    want medium format over 35mm for wide angles (other than the usual reason;
    that more film is better).
     
    Philip Homburg, Sep 30, 2005
    #41
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  2. We're talking about 25mm FOV and narrower here (see below), and at 21mm FOV
    and narrower, the Mamiya 7 _kills_ 35mm SLRs seventeen times over.
    My theory isn't that it's _easier_, it's that it's not any harder. My
    understanding is that things like the Super Angulons and what have you are
    very nice lenses, although the wider ones require center filters.
    It is common knowledge that you want large format over either for quality
    superwide. (Prior to the Stigma 12-24, superwide wider than 17mm was
    seriously bad quality.)

    Besides: we're not really talking about superwides here, we're mostly
    talking about 24mm FOV and over (about the best you can get using primes on
    APS-C cameras: the 14/2.8 lenses are horrendous dogs however much you trim
    them, leaving the 17/3.5 Tokina and 18/2.8 Nikon as the widest (25mm FOV).

    Remember: the claim was that you get better images by using the sweet spot
    of a full-frame lens, and to the best I can tell that's simply never true.

    David J. Littleboy
    Tokyo, Japan
     
    David J. Littleboy, Sep 30, 2005
    #42
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  3. Paul Flackett

    Chris Brown Guest

    Depends on what you want from the end-result. I've been using a 65mm Super
    Angulon recently, which is about as wide as you can go without requiring a
    specialist camera, without a centre filter and the corners aren't obviously
    darker than the results I get from the 43mm on the Mamiya 7 (Super Angulon
    is slightly wider). However, it's unusual to use LF lenses much faster than
    f/16 and this may have a bearing. I've never taken a shot with it wider than
    f/11 so I don't know what it would look like.

    One day I must get round to shooting some of my LF lenses wide-open, perhaps
    with Polaroids, just to see what the results look like.

    An aside, to return to the full-frame thing, here's a shot I took last night
    in the pub with the 5D and the 50mm f/1.4 lens, wide open at 1600 ISO, in
    yellow-filter B&W mode. I quite like the effect, and the B&W is quite useful
    to see the end-result in B&W on the LCD, even though the RAW has full colour
    info. In this case, the B&W looks OK, the colour looks vile, because of the
    nasty artificial light in there:

    http://narcissus.dyndns.org/Chris/5D_Candid.jpg

    5D, 50mm, f/1.4, 1/60, 1600 ISO, downsized for the web.
     
    Chris Brown, Sep 30, 2005
    #43
  4. Are there any samples online? Crops of edges and corners, preferably compared
    to similar shots on 35mm.
    Of course this is unlikely to be true for wide angles. For wide angles, you
    care about the corners and edges. If just the center is important, you can
    just as well use a longer lens.

    So a wide angle design is likely to compromise quality in the center to get
    better performance near the edges.

    However, I wonder what Nikon did with the 12-24 (other than reducing the
    aperture). It's MTF graph looks much better than the 17-35.
     
    Philip Homburg, Sep 30, 2005
    #44
  5. Paul Flackett

    Chris Brown Guest

    If you can wait a few hours, I'll do you a crop from a Mamiya 7 43mm shot
    (about 21mm equivalent in 35mm terms). I have a full-frame up, at 2400 dpi
    (about 33 megapixels), but I don't think my poor cable modem will stand the
    load if more than a couple of people decide to download it.

    The Mamiya 43mm f/4.5, btw, and the Super Angulons, are Biogon-type lenses.
    Such lenses tend to give excellent wide-angle performance, but the
    disadvantage of them is that they're essentially impossible to mount on an
    SLR, so they tend to be relatively unknown outside rangefinder and view
    camera circles.
     
    Chris Brown, Sep 30, 2005
    #45
  6. So it will be OK to buy and use the new 5D? <g>
     
    Scott in Florida, Sep 30, 2005
    #46
  7. And the camera body has what to do with that?
    [/QUOTE]
    The pixel size used in the camera body! Do you have the attention span
    of a maggot or something? This was the original statement only 4 posts
    back!
    Most manufacturers - what varies between them is the aperture at which
    their additional aberrations become insignificant compared to the
    diffraction limit. At full aperture the effect of diffraction is a
    minimum but other aberrations are at their maximum. As aperture reduces
    so do the aberrations, but the effect of diffraction increases. At some
    aperture, usually well within the working range for a decent quality
    lens it will become diffraction limited.
     
    Kennedy McEwen, Sep 30, 2005
    #47
  8. Paul Flackett

    Stacey Guest

    The pixel size used in the camera body! Do you have the attention span
    of a maggot or something? [/QUOTE]

    So again a poster turn to personal insults when their position is falling
    apart.

    BS, name ONE that is difraction limited which means at WIDE OPEN setting
    what is limiting the lens is the fstop size.

    Fricking DUH, of course you can stop ANY lens down to the point of it
    becoming a problem. That isn't what a "diffraction limited lens" is.

    Here's a clue for ya, maybe the CRAP lenses you are using have to be stopped
    down so far you NEED ISO 1600? Buy some decent glass (if it's made in your
    lens mount, if it's a wide angle it probably isn't..) and maybe you won't
    need a $3500 FF sensor camera.
     
    Stacey, Oct 1, 2005
    #48
  9. Paul Flackett

    Stacey Guest

    And that in the real world doesn't seem to cause other designs to suffer.
    Yet people DO mount these others to try to get decent WA performance from
    the EOS cameras, so again you've found a technical reason but in real world
    use, it doesn't make a bit of difference.
     
    Stacey, Oct 1, 2005
    #49
  10. So again a poster turn to personal insults when their position is falling
    apart.
    [/QUOTE]
    Just a valid observation that you have forgotten the topic within 4
    posts. You may well be indulging in selective quoting simply to avoid
    drawing attention to the fact that this was the reason the issue
    occurred, but that would have been deliberate deception on your part.
    Assuming you have limited attention span was giving you the benefit of
    the doubt!
    That wasn't the question you asked - and neither was it relevant to the
    argument. Wide open virtually all lenses are *worse* than diffraction -
    one reason why lenses are rarely used at full aperture, performance
    generally improves by closing down a few stops.
    You seem to have missed the point - but you lost the plot quite a long
    way back. It isn't a matter of closing the lens down till "it becomes a
    problem". If diffraction itself imposes resolution limits on the pixel
    size at useful apertures, which it certainly does with smaller pixels,
    then additional aberrations over and above diffraction only make the
    situation worse. You would have realised that if you had posed your
    question properly in the first place.
    Here's a clue for you, Bozo: I have never shot anything at 1600ASA in my
    life. 100ASA is as fast as I ever go - anything else results in too
    much degradation for most of my purposes.
    If you weren't stuck with a small format and consequently smaller pixels
    to achieve a useful pixel density then you wouldn't need impossible to
    achieve optical quality. The availability of larger format, affordable
    DSLRs removes that "God Barrier" and kicking and screaming against them
    because you happen to have over-invested in an intrinsically inferior
    format isn't going to change that.

    Inevitably, even larger format sensors than 35mm frames will become
    relatively affordable in due course and the same arguments will apply
    just as much to them. Whilst I don't need any more performance than the
    35mm format offers, I will be unlikely to buy any of them - but I won't
    go off in a tantrum trying to deny the laws of physics and claiming the
    smaller format is superior, the way you are behaving with your APS
    arguments. The only argument that is valid in the current comparison is
    "I don't need any more performance than APS yields" - so please refrain
    from telling us all *we* only need the same!
     
    Kennedy McEwen, Oct 1, 2005
    #50
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