Extension Tube and 100-300 measurements

Discussion in 'Accessories' started by ThomD, Aug 18, 2013.

  1. ThomD

    ThomD Mu-43 Veteran

    428
    Jun 1, 2013
    SF Bay Area
    When I started thinking about taking macro/close up work more seriously, everything I read pointed me in the direction of a macro lens. Unfortunately I missed Ken Rockwell's article that pointed out that moderate length macro lenses are not great for some insects because you have to get too close. So, while I like the 60mm macro, it wasn't really getting me what I wanted - dragonflies.

    Conventional wisdom is that ext tubes are not as useful at longer focal lengths because they don't make "that much" difference in magnification. Then Scott said, "get some tubes". So I did.

    What exactly do Kenko's Ext tubes get you on the 100-300? I'm glad you asked.


    Code:
    Focal Length         Ext Tube             Minimum Focus Distance   Horiz FOV
    300                        No                58"                       80mm
    300                        Yes               46"                       50mm
    
    200                        No                57"                       120mm
    200                        Yes               37"                       55mm
    
    100                        No                55"                       215mm
    100                        Yes               20"                       48mm
    
    The other change that Ext tubes bring is the loss of focus at infinity. A quick test shows that the far focus distance with tubes is 27" (68mm Fov) at 100mm and 76" (123mm Fov) at 200mm. I couldn't measure 300mm because the room was too small.

    Now I'm off to the local lake to look for bugs.
     
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  2. Zigstermeister

    Zigstermeister New to Mu-43

    8
    Aug 23, 2013
    Bellingham, WA
    Thanks for the info, I'm considering getting a set of tubes to use with that lens. Were these measurements with both tubes stacked? Or the 10mm or 16mm?
    I'd be interested in seeing your results.
     
  3. T N Args

    T N Args Agent Photocateur

    Dec 3, 2013
    Adelaide, Australia
    call me Arg
    My thanks too. I have just ordered tubes and I have that lens. I hadn't thought of them as a combo but I can see the sense of your post. Don't forget to post your results please.
     
  4. speedandstyle

    speedandstyle Mu-43 Hall of Famer

    Thanks for the chart. I haven't done much macro especially of insects but it sound like fun.

    They have a Dragonfly Festival here in Roswell every year out at the Bitterlakes Wildlife Refuge and having good macro would be very useful.
     
  5. ThomD

    ThomD Mu-43 Veteran

    428
    Jun 1, 2013
    SF Bay Area
    The tubes work great. The measurements in table were with both tubes. I can't say for sure that the tubes were on with these shots, but it is almost for sure - I keep the tubes on most of the time. Focus speed remains very quick on teh G6.

    CB-2013-02-L.

    P1060208-L.

    _1050099-L.

    P1060379-L.
     
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  6. speedandstyle

    speedandstyle Mu-43 Hall of Famer

    Awesome pics! Dragonflys are my favorite insect, so cool looking and colorful.
     
  7. ThomD

    ThomD Mu-43 Veteran

    428
    Jun 1, 2013
    SF Bay Area
    Thanks. The Dragonfly Festival sounds cool, but alas it is after school starts. Be sure to post your picts from it.
     
  8. T N Args

    T N Args Agent Photocateur

    Dec 3, 2013
    Adelaide, Australia
    call me Arg
    Hey! In-flight dragonfly, in focus..... not fair!
     
  9. ThomD

    ThomD Mu-43 Veteran

    428
    Jun 1, 2013
    SF Bay Area
    The trick to in focus, in flight is to pick your targets carefully. This guy kept coming back to the same perch, so he was easy to predict. (100-300 no tubes)

    CB-2013-01-L.
     
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