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Difference in bokeh quality - same lens - Photography

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  1. Moderated Post

    Default Difference in bokeh quality - same lens

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    G.T. Guest
    Moderated Post

  2. #2

    Default Re: Difference in bokeh quality - same lens

    Not a bokeh expert, but..

    Yes, the nature of the background (contrasts/shapes) certainly can
    affect the look of 'bokeh', even if it doesn't change the actual bokeh
    itself. And of course the relative distance to the background will
    also affect it, by changing how far out of focus it is.

    And yes, a difference in zoom angle, or setting the lens into macro
    mode (which for this lens probably involves moving internal elements)
    could certainly affect it, and the aperture (and particularly the shape
    of the aperture openeing at that setting) will affect it as well. I
    don't see how shutter speed could make a difference, unless the
    background was moving...!

    In the examples you posted, it seems to me that the main difference is
    that the background in the `nice` one (lovely shot by the way) is much
    more out of focus - in fact if you look at the one stalk of wheat (?)
    on the right that is much closer, it is beginning to show the same
    `bad` bokeh... I might add, I've seen MUCH worse!

    Chrlz Guest

  3. #3

    Default Re: Difference in bokeh quality - same lens

    OT: Yeah that's wheat and it is beautiful.

    Chrlz wrote: 
    paul Guest

  4. #4

    Default Re: Difference in bokeh quality - same lens

    G.T. <com> wrote:
     

    The greater contrast in the first image highlights the donut shape of
    the bokeh. You can especially see it in the white dots to the left.
    There's also the compositional problem of the stem that pokes into focus
    over the flower. It feels like it's poking you in the forehead. :-)

    The second image doesn't have as much contrast in the background, so the
    bokeh appears more even. If you look at the two highlighted leaves in
    the bottom right, you can see the distinct edges of the blur, but that's
    only because they're highlighted against a dark background. The rest of
    that individual plant is suitably blurred, given the lack of contrast.
    Nice pic. :-)
    Paul Guest

  5. #5

    Default Re: Difference in bokeh quality - same lens


    "Paul Mitchum" <c0m> wrote in message
    news:1gsicmv.mpk7hz1rjz219N%c0m... [/ref]
    linear in [/ref]
    shutter 
    >
    > The greater contrast in the first image highlights the donut shape of
    > the bokeh. You can especially see it in the white dots to the left.[/ref]

    Excellent, that explains it well.
     

    Hahaha, yeah, I printed a version with that cropped out. When I added a
    little more contrast that stem definitely looked like it was going to poke
    an eye out.
     

    Thanks.

    Other than the Tamron having an extremely stiff zoom ring I'm pretty happy
    with it.

    This is another ladybug shot using it on my 300D:
    http://homepage.mac.com/getosx/kimmie/ladybug1.jpg

    Greg
    --
    "destroy your safe and happy lives before it is too late,
    the battles we fought were long and hard,
    just not to be consumed by rock n' roll" - the mekons



    G.T. Guest

  6. #6

    Default Re: Difference in bokeh quality - same lens



    "G.T." wrote: 
    Good macro shot, but I am more interested in your hand, specifically
    that your third finger is considerably longer than the first. This
    appears to be an unusual occurrence, as I also have the same longer
    third finger, but I can find few other people with the same
    characteristic.

    Almost everyone's third finger is shorter than their first. (My first
    finger is my trigger finger on my 300D, just to stay on topic {:-)

    Colin.
    Colin Guest

  7. #7

    Default Re: Difference in bokeh quality - same lens


    "Colin D" <127.0.0.1> wrote in message
    news:127.0.0.1... 
    > Good macro shot, but I am more interested in your hand, specifically
    > that your third finger is considerably longer than the first. This
    > appears to be an unusual occurrence, as I also have the same longer
    > third finger, but I can find few other people with the same
    > characteristic.
    >[/ref]

    Very interesting, I had never heard that before. My toes are interesting
    lengths, too.

    Greg


    G.T. Guest

  8. #8

    Default Re: Difference in bokeh quality - same lens

    Colin D wrote:
     
    >
    > Good macro shot, but I am more interested in your hand, specifically
    > that your third finger is considerably longer than the first. This
    > appears to be an unusual occurrence, as I also have the same longer
    > third finger, but I can find few other people with the same
    > characteristic.[/ref]

    My 3rd f. is longer than my 1st by about 5 and 10mm (left/right resp.).

    The shot above is -not- macro.

    Cheers,
    Alan



    --
    -- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
    -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
    -- [SI] gallery & rulz: http://www.pbase.com/shootin
    -- e-meil: there's no such thing as a FreeLunch.
    Alan Guest

  9. #9

    Default Re: Difference in bokeh quality - same lens


    "Alan Browne" <ca> wrote in message
    news:cvnhlp$r4e$gazeta.pl... 
    > >
    > > Good macro shot, but I am more interested in your hand, specifically
    > > that your third finger is considerably longer than the first. This
    > > appears to be an unusual occurrence, as I also have the same longer
    > > third finger, but I can find few other people with the same
    > > characteristic.[/ref]
    >
    > My 3rd f. is longer than my 1st by about 5 and 10mm (left/right resp.).
    >
    > The shot above is -not- macro.[/ref]

    You're right, it's not. But as pretty much a beginner what makes a macro
    shot a macro shot?

    The Tamron 24-135 says it's a macro lens, it focuses as close as 16" and the
    mag ratio is 1:3.3. I didn't buy it as a macro lens so it doesn't matter to
    me. I also have the Canon 100 2.8 macro which I didn't have along on the
    above outing.

    Greg


    G.T. Guest

  10. #10

    Default Re: Difference in bokeh quality - same lens

    G.T. wrote:

    <snip>
     

    I guess you know that this excellent lens has compromised your personal
    information: fingerprint!


    --
    Frank ess


    Frank Guest

  11. #11

    Default Re: Difference in bokeh quality - same lens

    My fingerprint? I don't think so. That's a fake. Pretty good, huh?

    G.T. Guest

  12. #12

    Default Re: Difference in bokeh quality - same lens

    I think true macro reproduction is meant to be 1:1 or greater! But
    lens manufacturers seem to have hijacked the term and applied it to any
    lens that can focus closer than about 12"... (O;

    Chrlz Guest

  13. #13

    Default Re: Difference in bokeh quality - same lens

    Chrlz wrote:
     

    Yep. Real macros are 1:1 or better and not zoom.

    --
    -- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
    -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
    -- [SI] gallery & rulz: http://www.pbase.com/shootin
    -- e-meil: there's no such thing as a FreeLunch.
    Alan Guest

  14. #14

    Default Re: Macros (was Difference in bokeh quality - same lens)


    "Alan Browne" <ca> wrote in message
    news:cvql32$ggi$gazeta.pl... 
    >
    > Yep. Real macros are 1:1 or better and not zoom.
    >[/ref]

    As a beginner I'm not getting my head around the 1:1 ratio. What is being
    compared there?

    Thanks,
    Greg
    --
    "destroy your safe and happy lives before it is too late,
    the battles we fought were long and hard,
    just not to be consumed by rock n' roll" - the mekons



    G.T. Guest

  15. #15

    Default Re: Macros (was Difference in bokeh quality - same lens)

    G.T. wrote:
     
    >>
    >>Yep. Real macros are 1:1 or better and not zoom.
    >>[/ref]
    >
    >
    > As a beginner I'm not getting my head around the 1:1 ratio. What is being
    > compared there?[/ref]

    Very simply put, the image on the sensor is the exact same size as the subject.

    For example, if you photograph an insect that is 10mm long at the closest focus
    distance it will form an image 10mm long on the sensor (or film). This is a 1:1
    magnification ratio.

    For a Canon 20D, that would be about 1560 pixels, or a print of the 10mm insect
    of over 5 inches (at 300 dpi).

    SLR Macro lenses are typicaly fixed focal lenghts of 50, 100 (90, 100, 105) mm
    and a few longer FL's (such as the Sigma 180 macro).

    The only "true macro" zoom that I know of is the Minolta 50mm 3:1 f/1.7-2.8
    power zoom macro lens. In this case you get true mag up to 3 times (which
    doesn't sound like much until you see the photos n up on a slide
    projector...). But this lens demands a lot of patience to learn to use effectively.

    Not to be confused with zoom ratio (eg: where a camera manuf says this is a 3x
    lens meaning the focal lenght ratio is 3:1 (eg: a 100-300mm lens has a 3:1 zoom
    ratio, or "3x power" although)).

    Hope that helps.

    Cheers,
    Alan.


    --
    -- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
    -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
    -- [SI] gallery & rulz: http://www.pbase.com/shootin
    -- e-meil: there's no such thing as a FreeLunch.
    Alan Guest

  16. #16

    Default Re: Macros (was Difference in bokeh quality - same lens)


    "Alan Browne" <ca> wrote in message
    news:cvqnn5$rfa$gazeta.pl... 
    > >
    > >
    > > As a beginner I'm not getting my head around the 1:1 ratio. What is[/ref][/ref]
    being 
    >
    > Very simply put, the image on the sensor is the exact same size as the[/ref]
    subject. 
    focus 
    a 1:1 

    Got it, thanks.
     
    insect 
    105) mm 

    Yep, I have the Canon EF100.

    One last question on this: how does the 1.6x conversion of my Rebel effect
    the 1:1 ratio? I understand that it will be 1:1 on the sensor. I guess I
    could do the numbers like you've done with 20D.

    Thanks again,
    Greg


    G.T. Guest

  17. #17

    Default Re: Difference in bokeh quality - same lens

    On Fri, 25 Feb 2005 00:43:20 -0800, G.T. <com> wrote:
     
    >> Good macro shot, but I am more interested in your hand, specifically
    >> that your third finger is considerably longer than the first. This
    >> appears to be an unusual occurrence, as I also have the same longer
    >> third finger, but I can find few other people with the same
    >> characteristic.
    >>[/ref]
    >
    > Very interesting, I had never heard that before. My toes are interesting
    > lengths, too.
    >
    > Greg
    >
    >[/ref]
    That's because you're an alien freak!
    --
    Slack
    Slack Guest

  18. #18

    Default Re: Difference in bokeh quality - same lens


    "Slack" <net> wrote in message
    news:.. 
    > >
    > > Very interesting, I had never heard that before. My toes are[/ref][/ref]
    interesting 
    > That's because you're an alien freak![/ref]

    Shhhhh. Please do not disseminate that information.

    Greg


    G.T. Guest

  19. #19

    Default Re: Macros (was Difference in bokeh quality - same lens)

    G.T. wrote:
     [/ref]
    >
    > being

    >>
    >>Very simply put, the image on the sensor is the exact same size as the[/ref]
    >
    > subject.

    >
    > focus

    >
    > a 1:1

    >
    >
    > Got it, thanks.
    >

    >
    > insect

    >
    > 105) mm

    >
    >
    > Yep, I have the Canon EF100.
    >
    > One last question on this: how does the 1.6x conversion of my Rebel effect
    > the 1:1 ratio? I understand that it will be 1:1 on the sensor. I guess I
    > could do the numbers like you've done with 20D.[/ref]

    Again, it doesn't affect the image on the film plane at all. Just that the
    overall image is cropped around the edges. For DRebel, just look up the sensor
    width in pixels and mm and do the math.

    Cheers,
    alan


    --
    -- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
    -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
    -- [SI] gallery & rulz: http://www.pbase.com/shootin
    -- e-meil: there's no such thing as a FreeLunch.
    Alan Guest

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