Technical Imaging - Macro photography using a copy stand

Discussion in 'Equipment & Media' started by Pete Askew, Mar 3, 2012.

  1. Pete Askew

    Pete Askew Admin

    Hamish suggested it might be interesting to produce a series of 'articles' on technical imaging. This is the first in the series and follows on from the image of Speolepta leptogaster I posted a few weeks ago (http://www.realphotographersforum.com/specialist-macro-photography/3795-speolepta-leptogaster.html) as it demonstrates a similar technique using similar equipment. I chose to start with this both because quite a lot of our images for work are created in a similar way (but with lower magnification) and because, although these examples were achieved using medium format digital capture, the basic technique applies to any other camera system. A large copy stand was employed but, again, similar effects could be achieved using either a small copy stand or a tripod (maybe stood on a table).

    Here is the example image. It is a crop (as was the image of a fly) and has minimal adjustments made in LR/PS although I did 'delete' a couple of bits from the petals that I'd been too lazy to remove during shooting (actually it was quite fragile and picking them off may have damaged the surface). As with the fly, this is not what I would normally image (and I couldn't find another fly on the day!) but it illustrates the technique and also the limitations imposed by depth of field (many of my real subjects are flat(ish).

    [​IMG]

    As mentioned above, this is a crop from the final image as recorded and the original is below. The flower itself (a species of Pelargonium) is approximately 20 mm across. Given that the sensor (Phase One H20) is 40 mm x 40 mm it can be seen that reproduction ratio is ca 1.5:1. This was achieved using a Zeiss 135 mm f 1:5.6 CF S-Planar on Hasselblad auto-bellows at near maximum extension and two extension tubes (32 + 56 mm).

    [​IMG]

    The small flower itself is standing in a tube of water on a synthetic velvet background and is lit by two colour corrected Flo-Lite panels angled at approximately 45ยบ to the subject. The lens is fitted with a Lee lens shade.

    [​IMG]

    This shows the camera / bellows etc a little clearer.

    [​IMG]

    And this shows more detail of the lens, extension tubes and shade. The cable is the sync chord that connects to the Phase One back to trigger the capture - the body is a mains-powered ELM and so has no electronic coupling to the back and the lens has no interface either (Hasselblad / Zeiss never made an 'E' version of this lens). However, there is a cable that couples the integral motor drive so that you can trigger the capture from the computer (in this case after pre-releasing the mirror etc and waiting a couple of seconds to allow any vibration that causes to damp down - this makes a significant difference to image sharpness at this magnification and shutter speed).

    [​IMG]

    The subject was metered using a Sekonic L-608 from the baseboard using the dome closed (for direct incident readings) indicating a exposure of 1s at f1:22 and white balance was corrected using a Kodak exposure control card and the white balance tool in CaptureOne 6 which was used to capture the images from the H20 (which is a strictly tethered back). Often one would make an adjustment to the exposure indicated to compensate for the extension behind the lens used. In this case it would normally be about 2.0 f stops but a test shot indicated that it was actually closer to 1 f stop and so I chose to leave it uncompensated for this particular image as the petals were fairly reflective and producing quite a few specular highlights.

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    As I'm sure you realise, this is a completely manual setup and process including focusing. With the 135 mm Makro Planar focus is achieved using the stage as it has no internal focus and is optimised for close subject to lens distances. This is the view through the magnifying hood. Note of course that the image is reversed (and that my Phase One mask is upside down - I'd never noticed that before: not that is makes any difference as it is isn't recorded and is purely a guide to framing - annoying now though and I'll turn it over tomorrow!).

    [​IMG]

    And so finally, as this was more just a demonstration than an attempt to create a technical illustration I though I'd have a play with the final crop. And here it is!

    [​IMG]

    Hasselblad ELM (mains-powered version) + Zeiss 135 mm f1:5.6 CF S-Planar or Hasselblad Auto-Bellows + 56 and 32 mm extension tubes shot onto a Phase One H20 at 50 ISO into Capture One Pro 6, 1s at f1:22. PP in LR, PS, Nik ColorFX 4 and Nik SilverFX Pro 2.
     
    Last edited: Mar 3, 2012
  2. Hamish Gill

    Hamish Gill Well-Known Member

    That lot of extension there Pete
    Its probably a stupid question, but why is so much needed?
    Is the lens a 1:1 macro? this is making me question my understanding of how these things work...
    I thought extension just decreased minimum focusing distance?
    Im not sure im getting my head round this properly...

    I know the final photo is a bit of a bonus, non technical image, but its rather nice!!
     
  3. Pete Askew

    Pete Askew Admin

    The magnification ratio depends on lens to subject and bellows extension distance. Adding the extension tubes increases the magnification further and brings the lens closer to the subject (and reduces depth of field of course). Think of the image 'projected' behind the lens and all will become clear - don't forget in this instance there is no internal focusing to cloud the issue: and also the brightness decreases with the 'square' of the extension ('ish). Does that make sense?
     
    Last edited: Mar 3, 2012
  4. Hamish Gill

    Hamish Gill Well-Known Member

    Id be lying if I said yes...
    But the "Think of the image 'projected' behind the lens" does help ... I think ...
    I find this sort of thing hard to get my head around ... if it works it works ... :)

     
  5. Paul Lange

    Paul Lange Moderator

    Would it add any clarity if I said think of how a projector works. Move the projector away from the screen and the image becomes larger and dimmer. You have a fixed quantity of light but you are now spreading over a larger area. You can think of the the subject as the slide, the camera as the projector and the screen as the film back.Nice article Pete, I can see where a copy stand comes in fairly useful. I haven't done a whole lot of macro photography and generally rely upon VR, luck and continuous shooting!
     
    Pete Askew likes this.
  6. Peter Blake

    Peter Blake Member

    one question. I assume the flowlights are modern continuous lighting? the 135 being a leaf shutter design, wouldn't switching to flash be easier in terms of achieving better sharpness?
     
  7. Rob MacKillop

    Rob MacKillop Edinburgh Correspondent

    Wow.
     
  8. Pete Askew

    Pete Askew Admin

    You are right the Flolights are modern continuous units. I can easily switch to flash as they are carried on Hi-Glide rails and I can add our Bowens units in place. Certainly using undiffused tubes can create more contrast but if you diffuse them the effect would be similar. The main advantage of using the Flolights though is heat as the modelling lamps in the studio heads produce a lot of heat and they are near the subject (as well as your head). I also have an Elinchrom unit fitted with fibre optics that can be used to give very precise lighting without the heat near the subject but you can only run the modelling lamp in them for a relatively short period. Much of the effort in this sort of photography is getting the subject correctly positioned and lit to show the detail / feature that is required and so you often have the modelling lights on for a long time and only end up with one or two actual shots.
     

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