Can somebody explain ....

Discussion in 'Digital Photography' started by Mike, Oct 20, 2004.

  1. Mike

    Mike Guest

    I'm interested in using my 10D for some macro pictures but I am confused
    about which lens to get. I admit I don't understand much about macro - never
    having tried it before. I'd like to get a decent lens for this because I can
    use it for portrait work.

    Basically, I'd like to know about the ratios that are often quoted alongside
    these lenses. What does 0.5x or 1:1 actually mean? I'm considering the Canon
    100mm 2.8 USM because everything I've read is good. I'm not sure how useful
    it would be as a portrait lens though because it's quite long and there's
    the multiplier factor to consider as well. The 50mm macros I've seen seem to
    quote a 0.5x - does that mean it's inferior for macro work (but more useful
    for portrait)?

    Thanks for any help - macro really us uncharted territory for me, although I
    consider myself fairly clued up in other areas :)
    Mike, Oct 20, 2004
    #1
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  2. Mike wrote:
    > I'm interested in using my 10D for some macro pictures but I am confused
    > about which lens to get. I admit I don't understand much about macro -
    > never
    > having tried it before. I'd like to get a decent lens for this because I
    > can
    > use it for portrait work.
    >
    > Basically, I'd like to know about the ratios that are often quoted
    > alongside
    > these lenses. What does 0.5x or 1:1 actually mean? I'm considering the
    > Canon
    > 100mm 2.8 USM because everything I've read is good. I'm not sure how
    > useful
    > it would be as a portrait lens though because it's quite long and there's
    > the multiplier factor to consider as well. The 50mm macros I've seen seem
    > to
    > quote a 0.5x - does that mean it's inferior for macro work (but more
    > useful
    > for portrait)?
    >
    > Thanks for any help - macro really us uncharted territory for me, although
    > I
    > consider myself fairly clued up in other areas :)


    A "true" macro will reproduce a life size image on the recording media.
    On film that means a one inch bug will appear to be exactly one inch long on
    the negative. That is 1:1 ratio At a 1:2 or 0.5X, the bug would be ½ inch
    long on the negative. Many "macro" lenses need a extension which may or may
    not come with the lens to active the full 1:1.

    Digital does not come into play here as they are taking about the size
    of the image on the media so a 1:1 image on a 8X10 negative will be the same
    size, but include a subject area of 8X10 inches as a 35 mm camera image buy
    the 35mm image will not cover as much area and you digital may cover even
    less.

    Next thing to think about is the fact that there appears to be no legal
    definition of "macro" so you will find some manufacturers using the term
    loosely to refer to anything that may take a close up. Zoom lenses with the
    ability to focus reasonably close are often called macro, especially if they
    have a special setting to allow them to focus close. They may not focus
    close enough to get anywhere near life size 1:1.

    Also worth noting is that most true macro lenses are very sharp at
    normal distances and have been optimized for close work so they are
    outstanding at those distances. They also are usually corrected for a very
    flat field so when you are copying something flat like a stamp it will be
    sharp from the center to the edge, most lenses will not do that if you add
    extension tubes or close up lenses to focus that close.

    Good Luck
    --
    Joseph E. Meehan

    26 + 6 = 1 It's Irish Math
    Joseph Meehan, Oct 20, 2004
    #2
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  3. Mike

    GT40 Guest

    On Wed, 20 Oct 2004 16:42:48 +0100, "Mike" <>
    wrote:

    >I'm interested in using my 10D for some macro pictures but I am confused
    >about which lens to get. I admit I don't understand much about macro - never
    >having tried it before. I'd like to get a decent lens for this because I can
    >use it for portrait work.
    >
    >Basically, I'd like to know about the ratios that are often quoted alongside
    >these lenses. What does 0.5x or 1:1 actually mean? I'm considering the Canon
    >100mm 2.8 USM because everything I've read is good. I'm not sure how useful
    >it would be as a portrait lens though because it's quite long and there's
    >the multiplier factor to consider as well. The 50mm macros I've seen seem to
    >quote a 0.5x - does that mean it's inferior for macro work (but more useful
    >for portrait)?
    >
    >Thanks for any help - macro really us uncharted territory for me, although I
    >consider myself fairly clued up in other areas :)


    The 100mm macro is the way to go for you. The 1:1 means that an
    object is the same size on the image as it is in real life, 1:0.5 (or
    0.5x) means that the object is 1/2 of life size. A true macro lens is
    1:1 or better, Canon makes another macro lens that 1:1: - 1:5
    GT40, Oct 20, 2004
    #3
  4. Mike

    Alan Browne Guest

    Mike wrote:


    >
    > Basically, I'd like to know about the ratios that are often quoted alongside
    > these lenses. What does 0.5x or 1:1 actually mean? I'm considering the Canon
    > 100mm 2.8 USM because everything I've read is good. I'm not sure how useful
    > it would be as a portrait lens though because it's quite long and there's
    > the multiplier factor to consider as well. The 50mm macros I've seen seem to
    > quote a 0.5x - does that mean it's inferior for macro work (but more useful
    > for portrait)?



    Go for the 100mm for macro. It is a very good macro and pretty good portrait
    lens (on film).

    The crop makes it a bit severe for portrait, and you'll need a lot of room ...
    the result will be a bit flat looking for a head and shoulders shot.

    In macro, it is generally accepted that 1:2 (0.5x) or better is a 'macro' lens,
    but most claim 1:1 or better is the real deal.

    On film 1:1 means a 1/2 inch long feature (shot at 1:1) will be 1/2 inch long on
    the film itself (same for digtital wrt the sensor of course, but meaningless
    once stored). This means a lot of detail is captured.

    Even if the 50mm were 1:1, 100mm is better as it gives you more working room in
    front of the lens to get light in there.

    Pick up a basic (low cost) 50mm f/1.8 and you will have a very decent 1.5x
    portrait lens, or even an f/1.4 if that little bit more light and shallower DOF
    is important to you.

    Cheers,
    Alan

    --
    -- rec.photo.equipment.35mm user resource:
    -- http://www.aliasimages.com/rpe35mmur.htm
    -- e-meil: there's no such thing as a FreeLunch.--
    Alan Browne, Oct 20, 2004
    #4
  5. Mike

    Alan Meyer Guest

    "Mike" <> wrote in message news:cl611p$o8a$...
    > I'm interested in using my 10D for some macro pictures but I am confused
    > about which lens to get. I admit I don't understand much about macro - never
    > having tried it before. I'd like to get a decent lens for this because I can
    > use it for portrait work.

    ....

    I'll comment only on the portrait part of your question.

    A slight telephoto is good for portraits for a number of
    reasons.

    1. It lowers the depth of field at close ranges so you
    can isolate your subject from the background more
    easily.

    2. It prevents the lens distortion that one gets with
    wide angle lenses where, for example, a person's
    nose may show up bigger because it's closer to the
    lens than, say, the ears. It does this because of point 3.
    If you stand too close to the subject, you get that
    lens distortion.

    3. It allows you to stand back a bit from the subject
    and fill the frame with head or head and shoulders
    without being in the subject's face.

    I think that in the 35mm world, 75-100 mm lenses
    are commonly used for portraits.

    Alan
    Alan Meyer, Oct 20, 2004
    #5
  6. Mike

    Ken Burns Guest


    >1:0.5 (or
    > 0.5x) means that the object is 1/2 of life size.


    1:0.5 means the image is twice life size. 1:2 means the image is 1/2 life
    size.
    Ken Burns, Oct 20, 2004
    #6
  7. The prior posts address most of your questions. I'll add that the Sigma 105
    mm f/2.8 macro lens is worth taking a look at. I like mine.
    Charles Schuler, Oct 20, 2004
    #7
  8. Mike

    MB Guest

    I've only got Sigma lenses so far - three EX lenses covering all options
    from 16mm up to 500mm and yes, I'm satisfied with the results. I'm looking
    at Canon options after reading that their lenses are far superior (I want to
    see the results for myself!) I'll obviously give the lenses a test drive at
    the store first and I will add the Sigma to my list. It now consists of the
    Canon 100mm, the Tamron 90mm and the Sigma you mention. By the way, I am the
    OP - using my home computer instead of work!
    Thanks.

    "Charles Schuler" <> wrote in message
    news:...
    > The prior posts address most of your questions. I'll add that the Sigma

    105
    > mm f/2.8 macro lens is worth taking a look at. I like mine.
    >
    >
    MB, Oct 21, 2004
    #8
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