DSLR manual focusing issues

Discussion in 'Digital SLR' started by Peter Chant, Aug 22, 2009.

  1. Peter Chant

    Peter Chant Guest

    Auto focus works fine, but manual focusing, with either autofocus or manual
    lenses does not seem to. I've tested and the point that is in focus is
    sometimes in the right place, sometimes before and sometimes after the
    desired position. It seems to be inconsistent, if the focusing screen was
    out of position it would be consistent. Any thoughts apart from getting a
    split screen? PEntax k20d if that makes any difference. I never had this
    problem on my MZ-5n despite lack of split screen on that camera.
     
    Peter Chant, Aug 22, 2009
    #1
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  2. Could it be that the ease with which you can inspect every photograph
    at the highest possible resolution means that you simply now have much
    higher standards of sharpness and focus than you used to in film days?
    That's what happened to me. I also found to my great surprise that no
    matter how hard I tried, when working with critically sharp DoF, I was
    unable to nail focus completely accurately by manual methods. Using a
    tripod and taking several seconds over it I'd get it right about one
    time in three, whereas autofocus would nail it spot on in a fraction
    of a second.

    The difference is simply that in film days I'd rarely print as large
    as 12"x8", but now I check sharpness down to pixel level, a much
    higher standard. As a result I've also had to improve my camera
    steadying skills a lot too.
     
    Chris Malcolm, Aug 22, 2009
    #2
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  3. Peter Chant

    Paul Furman Guest

    Are you using the AF confirm light?


    --
    Paul Furman
    www.edgehill.net
    www.baynatives.com

    all google groups messages filtered due to spam
     
    Paul Furman, Aug 22, 2009
    #3
  4. Peter Chant

    Paul Furman Guest

    Live view zoomed in is great for tripod work, even though it doesn't go
    to full pixel zoom.

    --
    Paul Furman
    www.edgehill.net
    www.baynatives.com

    all google groups messages filtered due to spam
     
    Paul Furman, Aug 22, 2009
    #4
  5. Peter Chant

    Bruce Guest


    You asked for "any thoughts apart from getting a split screen?"

    Well, there is a simple answer. Get a split screen. The Katz Eye™
    screen will be familiar to anyone who has used a 35mm film SLR with a
    split image/microprism collar focusing screen, and it should eliminate
    the focusing errors that occur when focusing manually. Cost $105.

    http://tinyurl.com/9bvmjc
    or:
    http://www.katzeyeoptics.com/item--Pentax-K10D-K20D-Focusing-Screen--prod_K10D.html

    But I guess you didn't want to hear about that. ;-)
     
    Bruce, Aug 22, 2009
    #5
  6. Peter Chant

    Peter Chant Guest

    It does that. Rather awkward compared to using a viewfinder.
     
    Peter Chant, Aug 23, 2009
    #6
  7. Peter Chant

    Pete D Guest

    You can get viewfinder magnifiers for the K20D, some like them.
     
    Pete D, Aug 23, 2009
    #7
  8. Peter Chant

    H. Stiles Guest

    Not awkward at all if it's available right in the viewfinder too. As in
    most all P&S cameras with an EVF.
     
    H. Stiles, Aug 23, 2009
    #8
  9. Peter Chant

    H. Stiles Guest


    You've obviously never used many P&S cameras, and certainly not in
    telephoto, macro, and tele-macro modes where the DOF is every bit as
    shallow as any dSLR's. EVFs work fine for focusing with shallow DOFs. The
    EVF dot-pitch is just right in most all P&S cameras to work as a "reverse
    effect" micro-prism focusing aid even when not using magnified
    manual-focusing modes. I discovered a unique ability of EVFs about 9 years
    ago. Unlike a micro-prism ring in an OVF, where the little triangles in it
    scintillate if anything moving across it is out of focus, if any edges or
    textures are making the EVF's pixels scintillate then I know that those
    areas are in perfect focus. The exact opposite of how an optical
    micro-prism focus aid works. The finer in-focus edges and textures cause
    the pixels to rapidly change in luminosity as they pass between individual
    EVF pixels. Out of focus areas do not cause this due to the wider range of
    tones on the blurred edges and textures as they pass between EVF display
    pixels. Also not unlike how the more accurate (as opposed to less accurate
    phase detection) contrast detection focusing works, but I do it with my eye
    and using the EVF, instead of depending on the camera software and sensor
    to do the same when auto-focusing.

    Sony even expounded on this unusual but subtle principle of EVFs in some of
    their cameras a couple years ago, by including an option to color-highlight
    any edges and textures that cause this scintillating effect when in perfect
    focus in manual-focus modes. For manual focusing I'm able to detect exact
    focus across any area of the whole FOV at once, not just one little
    micro-prism ring in the center of an OVF. Anyone with a perceptive eye can
    do the same in any camera with an EVF. It takes practice to watch for this
    effect but once you learn to recognize when it happens and what it looks
    like this tool/method is always at your disposal for perfect and fast
    manual focusing in EVF equipped cameras. Once I taught myself this and
    other new ways of using EVF displays (having previously used OVFs all my
    life) I find EVFs more accurate and faster for focusing and more useful and
    brighter than any OVF on any camera I've ever used. No contest at all.

    You're never going to be able to convince me otherwise when I already know
    all of the above from personal experience. From your comment it's obvious
    that you don't possess the same -- experience.
     
    H. Stiles, Aug 23, 2009
    #9
  10. Peter Chant

    Peter Chant Guest

    Bruce wrote:

    Interesting site. Not cheap, I wonder how they compare to the pentax ones,
    not that I could find a pentax one with a quick google. Worth considering.
    I must compare the existing viewfinder with my ME Super.

    Pete
     
    Peter Chant, Aug 23, 2009
    #10
  11. Peter Chant

    Peter Chant Guest

    Chris Malcolm wrote:

    I don't beleive so, I took slides and also when scanning zoomed right in.
    If I'd had simplar problems with previous cameras I would have noticed.
     
    Peter Chant, Aug 23, 2009
    #11
  12. Peter Chant

    Peter Chant Guest

    Why is that? Backlash in the lens?
    Something to watch out for, thanks.
     
    Peter Chant, Aug 23, 2009
    #12
  13. Peter Chant

    Peter Chant Guest

    Paul Furman wrote:

    Sometimes. To be honest I've been shunning my MF lenses, although faster
    than my autofocus ones because of the focusing issues. Anti-shake plus AF
    zoom in poor light conditions seems to get a better result than faster
    manual lens plus anti-shake in poor light. Perhaps poor light has
    something to do with it.
     
    Peter Chant, Aug 23, 2009
    #13
  14. Peter Chant

    Miles Bader Guest

    BTW, anyone know why the name of the group is "...slr-systems", and not
    just "...slr"? The former seems an oddly awkward and clumsy name.

    -Miles
     
    Miles Bader, Aug 24, 2009
    #14
  15. Peter Chant

    Bruce Guest


    $105 is cheap, believe me. The Katz Eye screens offer excellent
    value. I use one in a Nikon D700 and one in a Canon EOS 5D. And as a
    former Pentax user (ME/MX/LX/Super A and others) I find the Katz Eye
    screens very easy to use.
     
    Bruce, Aug 24, 2009
    #15
  16. Not necessarily. With slides and film scans I too didn't notice the
    problems I now see in high resolution digital work, and going back to
    them I can't see any evidence of the problems I now face simply
    because in my film days I did not work to the same levels of
    resolution and rarely used the types of film or methods which would
    have made it possible to notice the differences I now easily see. I
    rarely used film and processing methods with fine enough grain, and
    when I did I rarely used camera stabilisation methods good enough to
    stop slight camera shake from blurring that degree of
    resolution. Going back to some of my best old film images I can see
    that not only was I not looking for such precision as I now do, but my
    then technique wasn't up to capturing it even when the film was.

    One of the big surprises of moving to digital for me was finding out
    how poor my long shot and critical focus techniques were, and how much
    learning and experiment I had to do to bring them up to the standards
    I now work to. For example, I used to boast that with care and no wind
    I could hand hold sharp images at least at 1/4 the shutter speeds
    recommended by the 1/focal length shutter speed rule. And I still can
    if I restrict myself to crisp 4"x6" prints :)
     
    Chris Malcolm, Aug 24, 2009
    #16
  17. Peter Chant

    Peter Chant Guest

    I am _certain_ that I would see the problems I am seeing now with film.
    Intesting to note that with my TLR I could get quite close in focussing
    before I flipped up the magnifier to check.

    Hmm, was it a waist level or live view viewfinder??? ;-)
     
    Peter Chant, Aug 24, 2009
    #17
  18. Peter Chant

    Peter Chant Guest

    Is the optibright coating worthwhile?
     
    Peter Chant, Aug 24, 2009
    #18
  19. Peter Chant

    Bob Larter Guest

    We argued all this when the group was being created. My own vote was for
    rec.photo.dslr, but the current name was the most popular option.
     
    Bob Larter, Aug 25, 2009
    #19
  20. Peter Chant

    Jeremy Nixon Guest

    It depends on your lenses. The tradeoff with the brighter screen is that
    it's less coarse, so you lose some amount of precision in seeing focus.
    But the non-bright ones become problematic with slower lenses.

    I didn't get the bright version. My suggestion would be that if you use
    slow lenses, like the zooms that have f/4.5 or f/5.6 at the long end,
    definitely get the bright version. If the lenses you normally use are
    all f/2.8 or better, then don't get it.
     
    Jeremy Nixon, Aug 26, 2009
    #20
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