More Macro Madness

Discussion in 'Digital SLR' started by Paul Furman, Oct 11, 2009.

  1. Paul Furman

    Paul Furman Guest

    Paul Furman, Oct 11, 2009
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  2. Paul Furman

    BobS Guest

    Jeeeezusssss - Don't you ever clean your pens......;-)

    That is really shallow DOF - wow !

    Bob S.
    BobS, Oct 11, 2009
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  3. Paul Furman

    Paul Furman Guest

    I already showed you how DSLRs are perfectly capable of stopping down
    and how there's a price to pay, in our last lesson, but I'll make it
    easier with a pair of crops.

    Crops side by side:


    Shallow DOF at f/16, notice the web-like hairs:

    Stopped down to f/90 lacks detail:
    Paul Furman

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    Paul Furman, Oct 11, 2009
  4. Paul Furman

    Paul Furman Guest

    Yeah, though it's the nature of extreme closeup work if you remember
    using a microscope in school. A better lens would probably help too. The
    other example crops are a 105 macro lens but the 2x teleconverter
    stretches it's abilities, butchering the bokeh and this is stretched
    wayyyy beyond intended use as well, the 50mm lens has a closest focus of
    only 2 feet. The beauty of this setup is it's compact & no tripod
    needed. If I put the big 105 on the bellows and a tripod it would be
    very unwieldy. That's why they make bellows lenses.

    Yes, though it gets soft all over:
    -that's f/22 on the 50mm lens, the other was f/8, hard to tell much in
    this case, see the crop examples in my other reply for a more extreme
    comparison with true f/numbers. The bellows changes effective aperture,
    here's a formula for the bellows extension:

    So f/8 is f/32 and f/22 is f/88 assuming the reversed lens on front
    has no effect which I think is true. If I stop down the front lens, it
    vignettes severely.

    Wow, so wide open at f/1.8 would be f/7.2 and f/4 is really f/16.

    focal length plus extension times f/number divided by focal length

    Nikon Series-E 'pancake'(reaches 8:1 with reversed 35)
    (50+150mm) * f/1.8 / 50mm = f/7.2
    (50+150mm) * f/2 / 50mm = f/8
    (50+150mm) * f/4 / 50mm = f/16
    (50+150mm) * f/8 / 50mm = f/32
    (50+150mm) * f/22 / 50mm = f/88

    Spiratone macrotar (reaches 5:1 alone)
    (35+150mm) * f/3.5 / 35mm = f/18.5
    (35+150mm) * f/4 / 35mm = f/21
    (35+150mm) * f/8 / 35mm = f/42
    (35+150mm) * f/16 / 35mm = f/84

    El-Nikkor (reaches 7:1 with reversed 35)
    (80+150mm) * f/5.6 / 80mm = f/16
    (80+150mm) * f/8 / 80mm = f/23 <- optimal
    (80+150mm) * f/16 / 80mm = f/46
    (80+150mm) * f/32 / 80mm = f/92

    Paul Furman

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    Paul Furman, Oct 11, 2009
  5. Paul Furman

    Richard Guest

    OK. I asked you before how you would do stuff like this. Paul replied with a
    whole bunch of informative stuff. From you... nothing. Are you going to come
    up with something constructive or what?

    Thank you.
    Richard, Oct 11, 2009
  6. Paul Furman

    Paul Furman Guest

    I haven't tried software, sometimes manually patching together:

    Ack, I'm going to need to look into that, I just tried an old projector
    lens in front of the 80, the best results yet... which means it really
    is better a little wider like f/8 which is f/23 if you figure extension.

    Paul Furman

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    Paul Furman, Oct 12, 2009
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