Speolepta leptogaster

Discussion in 'Equipment & Media' started by Pete Askew, Jan 19, 2012.

  1. Pete Askew

    Pete Askew Admin

    This is something I would not normally shoot and certainly not in this way. This is a shot of Speolepta leptogaster collected during a recent piece of work. The main study is on microbial colonisation of the surfaces at an enclosed historic site to help identify a conservation approach that can limit its deterioration. We have identified the main fungus in the system but there are other components of this ecosystem that are contributing to the deterioration of the paintings. One of which are larvae, presumably feeding on the fungi. I had sub-contracted the work on the larvae and fly to another laboratory but they were unable to identify the fly nor say whether the larvae was associated with it. So I had to do this myself, which proved relatively straight forward. Normally I would photograph a specimen like this either through a microscope or using our Zeiss Tessovar (The Zeiss Tessovar - a macro legend | Pixiq) but I am in Germany and they are in the UK and the specimen was sent back to me here. So I used a macro setup instead consisting of a Hasselblad 503CW + Zeiss 120 CF Macro Planar f1:4.0 (stacked on 3 extension tubes - 16 + 32 + 56 mm) onto a PhaseOne P20 back (set at ISO 50) mounted on a copy stand. The specimen was placed directly onto a colour corrected lightbox next to a transparent ruler (mm) and metered using a Sekonic L-758D (incident - dome closed) giving an exposure of 1/4s at F1:11. After focusing, the mirror was pre-released and the shot taken using the back tethered to CaptureOne Pro. White balance was checked against the face of the lightbox (no correction was required) and no adjustment of the exposure was made. It was exported as a 16 bit TIFF then cropped to about 75% of the original image area. The back has no anti-aliasing and so no RAW sharpening was required but it was output sharpened in Nik Output sharpener in PS and a fine border added.

    Speolepta leptogaster

    [​IMG]


    Macro setup used.

    [​IMG]

    Hope this is of interest.
     
    Last edited: Feb 28, 2012
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  2. Chris Dodkin

    Chris Dodkin West Coast Correspondent

    Very nice set-up Pete - that copy stand brings back memories, I'm sure I had the same or similar at Uni for my research.

    The resulting image is so clean that it almost has a 'line drawing' quality to it - it reminds me of the drawings in my parent's old leather bound Britannica Encyclopedia set.

    Do you meter for colour temp, or do you rely on the illumination being a specific colour temp in the light box/lighting?

    I've used a Gossen MasterSix with ProfiColor in the past to confirm colour temperature, and set my camera to that, rather than relying on AWB or a preset. It's been very effective when shooting multiple subjects from the same set-up, with widely varying overall colours.
     
  3. Brian Moore

    Brian Moore Moderator

    ...of interest...? Its fascinating!

    First,...what's a "medieval cave painting"? I (and I suppose others) typically associate cave paintings with pre-historic man. The Middle Ages, of course, fall within the historic period. So I'm curious what such paintings are.

    Secondly,...do you contribute to such restoration/preservation activities on a regular basis, Pete, or is this unusual?

    Third, your description of your process is very informative. Most of us--me included to be sure--wouldn't know where to start.

    Finally,...it's a bonnie wee beastie ye'v took a fotie of.

    Thanks Pete.
     
  4. Pete Askew

    Pete Askew Admin

    Thanks Chris. The DeVere copy stands are based on their enlargers and a just about as stable as you can get. I love them.

    Normally I do meter for colour (Sekonic C0500R in Germany and a Sixticolor in the UK) and set that in CaptureOne but this lightbox is very accurate and CaptureOne gave it about 100K over what I measured so I left it as is, as I suspected it would rise as the tubes warmed up a little and I didn't start a new session for the job.
     
  5. Hamish Gill

    Hamish Gill Well-Known Member

    Fascinating Pete... really interesting to get an incite into your work!
    And yeah... basically, what Brian said ...

    Just purely out of interest, im not thinking of trying to source one at all ... Honest ...
    How would you say a p20 stacks up against a d3 in day light conditions?
    The bigger and higher quantity of pixels make a BIG difference?
     
  6. Pete Askew

    Pete Askew Admin

    To be honest, it walks all over my D3!! Both in terms of dynamic range, resolution and colour fidelity. In low light the P20 (16MP) is next to useless! I used it for this shot as the P45 (39MP) is H fitting and I knew I needed to put new batteries in the H1/2 and the 503 was already out. That would have given me even more resolution if I'd needed it (which I didn't). I was using a D700 on my Tessovar but have passed that on now as I don't particularly like it as a general camera (I prefer the handling and menus etc of the D3) and am intending to replace it with a D3x as the resolution was occasionally lacking with the D700 / D3.

    If you don't mind shooting tethered, then the H20 is very good value (S/H) and some of the older backs are more than competent and able to match the image quality of a D3.
     
    Last edited: Jan 19, 2012
  7. Hamish Gill

    Hamish Gill Well-Known Member

    tethered only doesn't appeal to me
    low light will always be the d3's area...
    but in daylight I would want something to be a big step up from the d3 to ever be able to justify it... Im guessing a P20 would cost big money for that big step up then...
     
  8. Pete Askew

    Pete Askew Admin

    Well historic materials are by no means my main area of work but I am, and IMSL is, focused on the microbiology of materials although usually modern industrial materials (and processes). And microorganisms don't really 'care' how old something is and so we occasionally get to work with historic materials. It is an area which we are getting more involved in since being part of am EU-funded project and in which I have an interest.

    Quite a few cave systems were used as either sanctuaries or dwellings both in pre-hisorical times and the middle ages (and in more recent times of course) and a number were carved and decorated. The one I am working on at present dates from this period but it is not clear if was a natural structure or was excavated (I cannot disclose any more detail due to the contract) but it was decorated (carved and painted with a mixture of Christian and pagan iconography) in mediaeval times.

    The main issue with scientific recording is accuracy (scale and geometric and colour accuracy) accompanied with showing the details etc that are important for the task. Hence the images are often not especially asethetically pleasing but they are accurate depictions of what was there. So you need equipment that is highly corrected optically and accurate methods to measure exposure and colour temperature and use a forensic approach to image processing. In many instances, the final images are pretty meaningless when out of context but they serve as the record associated with a finding or the analytical process.

    As an example, here is an image from the same job, in this case showing a critical feature used to identify the main species of fungus present on the stone (and presumably therefore the source of food for the larvae of the Fungus Gnat). It's confusing if you do not know what you are looking at especially if you do not know the scale (the slightly ovoid structure just off centre is about 6 µm across). This is often a problem with micrographs as the depth of field is pretty small (probably less that 1 µm in this instance), the lighting (in this case phase contrast) is designed to amplify edge contrast to help visualise structures (but creating highlight on areas that are out of focus) and when you are viewing in real time you can focus up and down to analyse the view. The photograph, of course, just shows one plane. In some instances you can use image stacking to provide more 'clarity' but often with wet preparations - like this - it generates too many artefacts. The challenge is to record the elements that are important and not be selective to hide things that contradict ones conclusion.

    Well, you did ask!! :)

    [​IMG]

    Wet mount from a 5 day old culture of Gliomastix murorum on Sabaroud Dextrose Chloramphenicol Agar (20ºC) showing hyphal bundles. Viewed and imaged on a Nikon Optiphot using Phase Contrast illumination (tungsten source) plus 40x PH objective and 12.5x Nikon projection lens onto a Fuji S5 Pro controlled by Fuji Hyper Utility 3 shooting software. Colour correction in LR and output sharpening in Nik Output Sharpener Pro
     
    Last edited: Jan 19, 2012
  9. Pete Askew

    Pete Askew Admin

    I guess a good S/H P20 would be about £3-5K and a P45 about £10K. (but there are some good buys sometimes eg, Used Phase One P21 Hasselblad V Fit Digital Back : Teamwork Digital Ltd, Suppliers of Professional Digital and Large Format Photographic Equipment). I guess a new back of about 39MP would be in the region of £15K.
     
  10. Hamish Gill

    Hamish Gill Well-Known Member

    I think I need to put this idea seriously on the back burner ... that money could buy me a lot of other much more worth while kit ... If i even had that sort of money ...
    sorry to trespass on an otherwise very interesting thread ... :)
     
  11. Brian Moore

    Brian Moore Moderator

  12. Pete Askew

    Pete Askew Admin

  13. Pete Askew

    Pete Askew Admin

  14. Pete Askew

    Pete Askew Admin

  15. Brian Moore

    Brian Moore Moderator

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  16. Pete Askew

    Pete Askew Admin

    An update on this very old thread (especially for @Brian Moore). I was approached last week by the trustees of the cavern to ask if they could use the images produced for the reports. This was fine with me and so I provided them with ones for the website and (later on) a brochure.

    https://www.roystoncave.co.uk/post/worms
     
  17. Rob MacKillop

    Rob MacKillop Edinburgh Correspondent

    ...and they were very surprised, as they asked for shots of The Cavern in Liverpool! :D

    You're a pro, sir!
     
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  18. Pete Askew

    Pete Askew Admin

    I did spot a few beetles at the time! :)
     
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  19. Rob MacKillop

    Rob MacKillop Edinburgh Correspondent

    Haha!
     

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