1.5X Sensors VS. Full Frame and other questions...

Discussion in 'Digital Photography' started by Progressiveabsolution, Apr 27, 2006.

  1. You definitely win that one, Jeff.

    David Littlewood, May 6, 2006
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  2. Progressiveabsolution

    l e o Guest

    The cropped bicycle clearly showed that the hand held one is not as
    sharp as the other one using tripod. It's not DoF issue. the difference
    is small but identifiable. If you ever want to defend this issue
    systemically, you should have shot at the same f/4.8 with the tripod. :)
    l e o, May 6, 2006
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  3. Progressiveabsolution

    Alfred Molon Guest

    I also shot the scene at F4.8 with a tripod and the bycicle is still

    Clearly this is a DOF issue. In the (tripod) F14 shot I posted the
    bycicle is sharp because at F14 there is more DOF.

    In the handheld shot the parts of the image which are in focus are
    sharp, despite the 1/30s exposure time at 120mm equiv. focal length.
    Alfred Molon, May 6, 2006
  4. Progressiveabsolution

    Mark² Guest

    Did you read my post regarding lens sharpness when stopped down that is not
    DOF helps a lot, but there's more to it than that.
    You didn't respond.

    Here's the post again:

    There is more to it that increased DOF.
    This is an aspect of lens sharpness that hasn't seemed to register in your
    mind (at least not in your posts).

    *Nearly all lenses render sharper images when they are stopped down...and
    this doesn't necessarily have ANYTHING to do with DOF considerations. Check
    any site that does lens tests at various apertures and you'll find that the
    overwhelming majority of lenses perform their best (in terms of sharpness)
    when stopped down to around f8 to f11.
    **This is further emphasized by noting that their test targets are
    flat...(zero depth grids, patterns, etc...)
    See dpreview.com tests if you're unfamiliar with these.

    This is something I've been trying to convey to your, Alfred. -That
    stopping down allows a lens to perform not only in terms of DOF, but also
    allow it to take greatest advantage of sharpness that has nothing to do with
    DOF. Of course DOF is a factor in creating focus front-to-back, but DOF
    needn't enter the equasion at all to benefit from sharpness that is inherent
    in stopping down nearly any lens.

    This is most noticeable in portions of the frame that are not centered.

    This is basic optics stuff, and worth looking into.
    Don't take my word for it. Have a look for yourself.
    Here's an example:
    While I'm not a Sigma fan (that's putting it lightly!), this page DOES have
    a great series of identical shots which clearly show the benefit of smaller
    apertures as they relate to sharpness...and NOT just from DOF.
    **Scroll down to where it shows images of book spines on a shelf at
    different apertures. It is very revealing, and key to what I've referred
    Check it out...
    Mark², May 7, 2006
  5. Progressiveabsolution

    Alfred Molon Guest

    If I reply to everything you write, we have a nice never ending loop.
    Yes, I know about this. But there is no law of physics which states that
    lenses cannot be sharp when wide open. The lens of the Olympus 8080 for
    instance has corner-to-corner sharpness even when wide open. The problem
    seems to occur mostly with DSLR lenses.

    The question is if the Sony R1 has a lens which is corner-to-corner
    sharp when wide open. So far I have no evidence to the contrary. If you
    examine again this shot:

    1/30s, F4.8, 120mm, handheld

    you will note that the bottom right corner is sharp, almost as sharp as
    the tripod F14 shot

    with the little extra sharpness you see in the F14 shot most likely
    related to greater DOF.

    The right bottom corner of the handheld F4.8 shot is unsharp, but this
    is due to a lack of DOF, because if you look at the right bottom image
    border you will see above the black and orange car a piece of the
    yellow-white roof of the petrol station (which is at a different
    distance than the hosuse).

    This piece of roof is tack sharp, despite being at the extreme end of
    the image. If there was a corner sharpness issue, this would't be the
    case. Have a look for instance at the image corners of the samples of
    the 5D at dpreview.
    Alfred Molon, May 7, 2006
  6. Progressiveabsolution

    Mark² Guest

    That's really weak, Alfred.
    There was nothing inflamatory in my post. It was merely informational.
    You have been presented with information that clearly indicates a detail
    you've previously missed.
    Now it appears you are simply ignoring it in order to avoid getting the
    point, and acknowledging that there really is something to what I've been
    saying all along.

    I'll take your silence as indication that you now, finally, see what I've
    been referring to all along.

    Mark², May 7, 2006
  7. Progressiveabsolution

    ASAAR Guest

    Oh my. Faulty assumptions make it so easy to draw faulty
    conclusions. You do that so well.

    And I'll take your sustained silence (re. answering my question
    about the lack of camera movement) as an indication that you saw
    what I was referring to all along, and simply didn't want to admit
    that you had been mistaken. Alfred's decision to not respond to
    your irrelevant question shows much greater maturity than if he had
    simply relegated you to his klink file, don't ya think? <g>
    ASAAR, May 7, 2006
  8. Progressiveabsolution

    Alfred Molon Guest

    What silence? I *did* reply to your post. Check again.

    Besides, even if I din't reply, it wouldn't mean that I agree with you.
    Mark, I have other things to do in life besides replying to usenet
    Alfred Molon, May 7, 2006
  9. Progressiveabsolution

    Mark² Guest

    What I'd like to know is why I'm even seeing you here again.
    Did you change your info?

    Perhaps it would be better at this point to let Alfred make his own
    arguments. Surely he can speak for himself.
    This does, after all, have nothing to do with you or your photographs (do
    you have any? -Never seen 'em).

    In any event... I will now klink you again.
    I know you miss me, but don't change your e-mail just so I can see you
    Oh, and did I mention you're a hypocrite?
    Bye bye, chump.
    Mark², May 7, 2006
  10. Progressiveabsolution

    Mark² Guest

    May you have many years of happy snapping.
    Take care.
    Mark², May 7, 2006
  11. Progressiveabsolution

    ASAAR Guest

    Nope. I'm using the same info. I started with in 2004. It's you
    or your computer that's at fault. I knew that you were in need of
    some self-scrutiny but I didn't think that it would come to this. :)

    He has been speaking for himself and has been doing a fine job of
    it. You don't like hearing my POV so you've resorted to your
    "klink" file, which has an uncanny knack of failing. I don't use OE
    so I'll let you try to figure out what your problem is.

    I've posted links to a few, and as far as I'm aware they're still
    visible. If you want to see them, search your archives or google's.
    I wasn't aware that one needed to make photos available in order to
    post replies.

    Suit yourself. Why would I miss you? After all, unlike you I
    don't need to resort to putting a bag over my head. All of your
    messages are visible. If they're in a thread of interest I'll
    download them. Otherwise they exist only as headers and eventually
    vanish. As I've said, nothing has changed. That is, at least for
    several months. If anything had been changed it would have been
    minor and inadvertant, and only due to reinstalling software after a
    crash, but not to try to bypass your ineffective filters.

    And you're a mendacious coward that appears to live for the
    opportunity to hurl invective and insults when you're proven wrong
    and are unwilling to admit it. Bye bye, champ. I'll see you again
    soon, the next time your klink file fails, or when you'd have reason
    for us to believe that growingly lame excuse . . .
    ASAAR, May 8, 2006
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