Kenko Extension Tubes on 35-100 2.8 or dedicated macro

Discussion in 'Native Lenses' started by webarchitect, Aug 31, 2015.

  1. webarchitect

    webarchitect Mu-43 Regular

    Sep 15, 2010
    I'm working on an industrial fine arts project and need some new equipment, but what? Quality is paramount as the final product will be prints on 20x30 aluminum sheets. The subject matter is also aluminum, left over cut out sheets of aluminum from a machine shop. Imagine the possibilities...

    I don't have a macro lens, but do have the Panasonic 35-100 f/2.8. The attached image is shot at 100mm at the closest focus setting. I don't have access to a store that carries the Kenko extension tubes but they sound promising. Anyone have some experience with the 35-100 2.8 they can share? How much closer can you focus? Can you get 1:2 life-size?

    Would a macro lens be better?

    Or perhaps I'm overlooking something?

    This should be a very cool project with amazing images in the end. Thanks for your input!

    Attached Files:

  2. Dave in Wales

    Dave in Wales Mu-43 All-Pro

    Nov 5, 2011
    West Wales
    Last edited: Sep 1, 2015
  3. wjiang

    wjiang Mu-43 Hall of Famer Subscribing Member

    I have both tubes and achromats, and I find front mount achromatic dioptres tend to work better, especially with telephotos. Extension tubes tend to expose all sorts of lens aberrations from being focussed way too close, whereas good achromats have much less impact.

    I have some legacy 58mm +1.6 and +3.3 achromats that would work very well with the 35-100, have a lookout for cheap deals.

    Have a look here for magnification calculations with tubes or dioptres:

    Neither tubes nor achromats on standard lenses are quite up to the flat field razor sharpness of the 60mm macro for super fine macro detail though...
    • Agree Agree x 1
  4. Phocal

    Phocal Mu-43 Hall of Famer

    Jan 3, 2014
    1 - Pretty sure you will not reach 1:2 with tubes but I am probably wrong.

    2 - Yes, a true macro lens would be better. If IQ is truly important just get a true macro lens (the Oly 60 is an amazing lens) and be done with it.
  5. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    It's very hard to beat the detail a real dedicated macro lens can pull out of a subject however I suspect the most challenging part is going to be lighting it rather than which lens you use to take the picture.

    A ruler showing 1:2, same setup as the second shot. Rodenstock 40mm APO @ F/11.

    Cross polarized lighting won't work as the subject is metal, given the working distances involved for 1:2 it rules out many studio lighting options (due to both size and power levels). The main options are probably either a ring flash (which means you can't shoot the subject flat field due to specular reflection (which will be a problem regardless)) or a separate flash head setup (probably the best option to introduce depth to scratches using more directional light).

    1:2 of bolts showing machining marks and issues with specular highlights due to ringflash on metal (and punishingly small DoF, Rodenstock 40mm APO @ F/11.).

    Edit: I just thought I should add, at normal distances to light metal you would light and flag the surround to give the effect you desire, it's just much harder to achieve at macro distances because a huge amount of the surround is the camera.

    Either way it sounds like a lot of fun, I would love to see the results :)
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