Focus Stacking with a Raspberry Pi – Mould Macro Photography Project

    image 10mm x 10mm sample mold growing on sliver beet root - six days old.
    image  coverage 10mm x 10mm; mold growing on sliver beetroot – six days old.

    In the search for interesting things to photograph on a macro scale using my focus stacker, it was suggested to me by Sara that mould might be worth looking at – well, it is!

    I started off with a 10mm sliver of beetroot less than a week ago and it is already producing lots of mould growth. I placed the piece of beetroot on a small polystyrene foam-board tray in a sealed plastic container and put that in a cupboard where it would be in the dark and stay warm. Within three days I had a few circles of white mould with one starting a grey centre.

    Three days later the surface was covered in interlocking circles of mould – all grey except one which is very yellow. The white/grey mould is like little flowers and the yellow mould is like small pom-poms. It will be interesting to see what happens next.

    I have reproduced some of the images from my focus stacker here. I have some other food items in my test lab waiting to see what will happen to them.

    The image above was taken at a magnification of approximately 0.5 and cropped to show a 10mm sample width – taken with a Tamron 90mm SP lens without extension. Low magnification images were taken with a  Nikkor 50mm enlarger lens at f 5.6 reversed onto 135mm Minolta MD lens at f 3.5 giving a magnification of 2.7 – focus increment of 100microns – varying numbers of images. Higher Magnification images were taken with a Componon 28mm enlarger lens at f4.8 reversed onto a 200mm Minolta MC lens at f8 giving a magnification of 7.1 – focus increment of 20 microns – varying numbers of images. Images were all stacked in Zerene Stacker.

    Click on any image for a slide show of the hidden world of mould (I never thought I would be typing that!)

    Componon 28mm reversed onto Minolta 200mm lens. Focus increment 20 microns, 251 images. Day 3 of mould growth.
    Componon 28mm reversed onto Minolta 200mm lens. Focus increment 20 microns, 251 images. Day 3 of mould growth. No yellow mould apparent yet. Lots of beetroot still showing.

     

    Nikkor 50mm reversed onto Minolta 135mm lens. Focus increment 100 microns, 164 images. Day 6 of mould growth.
    Nikkor 50mm reversed onto Minolta 135mm lens. Focus increment 100 microns, 164 images. Day 6 of mould growth. Yellow mould apparent. No surface of the beetroot showing.
    Componon 28mm reversed onto Minolta 200mm lens. Focus increment 20 microns, 88 images. Day 6 of mould growth.
    Componon 28mm reversed onto Minolta 200mm lens. Focus increment 20 microns, 88 images. Day 6 of mould growth.
    Nikkor 50mm reversed onto Minolta 135mm lens. Focus increment 100 microns, 57 images. Day 6 of mould growth.
    Nikkor 50mm reversed onto Minolta 135mm lens. Focus increment 100 microns, 57 images. Day 6 of mould growth.
    Componon 28mm reversed onto Minolta 200mm lens. Focus increment 20 microns, 133 images. Day 6 of mould growth.
    Componon 28mm reversed onto Minolta 200mm lens. Focus increment 20 microns, 133 images. Day 6 of mould growth.
    Componon 28mm reversed onto Minolta 200mm lens. Focus increment 20 microns, 283 images. Day 6 of mould growth.
    Componon 28mm reversed onto Minolta 200mm lens. Focus increment 20 microns, 283 images. Day 6 of mould growth.
    Nikkor 50mm reversed onto Minolta 135mm lens. Focus increment 100 microns, 100 images. Day 6 of mould growth.
    Nikkor 50mm reversed onto Minolta 135mm lens. Focus increment 100 microns, 100 images. Day 6 of mould growth.

     

     

    Beetroot Mould Componon 28mm reversed onto Minolta 200mm lens. Focus increment 20 microns, 189 images. Day 3 of mould growth.
    Beetroot Mould Componon 28mm reversed onto Minolta 200mm lens. Focus increment 20 microns, 189 images. Day 3 of mould growth.

    Focus Stacking with a Raspberry Pi – One year On

    It is more or less a year since I got my focus stacker working, and there have been many developments and changes to the set-up during this time.

    What’s good?

    • Interfacing with the RPi using a laptop running MobaXterm is straightforward and the built in editor is really handy
    • The concept of moving the specimen and not the camera works well – the moving parts are very light weight with hardly any inertia, and vibration is not an issue.
    • The Componon 28mm lens is a dream – so sharp
    • Continuous lighting using a light box lit from below is a simple solution to provide even diffused lighting
    • The whole focus stacker rig works, and produces very acceptable extreme macro images
    • It has kindled an interest in entomology and insect anatomy

    What’s not so good?

    • Getting real time into the RPi automatically – should be easy!
    • Setting up the specimen is still fiddly – but not as difficult as it was before the jack and the rack
    • Cleaning and mounting the specimens – and there is nothing that can be done about that other than doing it!

    What next?

    • Fix RPi real time – somehow DONE
    • Build a bigger light box to give more room around the specimen for adjustment DONE
    • Take more stacks
    • Improve my insect identification and understanding of  insect anatomy

    And then? 

    • A  3-axis (of spin) specimen mount – motorized – remote controlled – ha ha!

    Focus Stacking with a Raspberry Pi – Specimen Adjustment for Easier Framing and Composition

    Focus stacker
    Focus stacker without light box. The lab jack visible beneath the specimen.

    Over the past month I have made some further improvements to make life easier to set up the specimen and to take the stacks.

    Finally a simple manual lab jack arrived from China which will give me 5mm of vertical adjustment. This is so small that it fits neatly on the stage, having a footprint of just 25mm x 25mm and weighing next to nothing.

    On top of this I have mounted a thin steel plate. All my plastic specimen mounting cards now have a very thin button magnet glued to them, which holds them tightly to the top of the jack while allowing rotation in the horizontal plane and z-y movement.

    lab jack
    lab jack

    At the camera end of the business there is now a second rail mounted laterally which allows fine adjustment in this direction to frame the image. This came from one of the many suppliers of such things on Ebay. It is not a precision item like the lab jack, but will do the job required at very reasonable cost.

    There is an additional light fitted at the front which is used to illuminate the stage while setting-up and provides enough light for the camera to see the specimen and to enable fine tuning of the camera and specimen positions. The main lights are now fixed to the equipment chassis and not the underframe which makes adjustment of the equipment chassis position relative to the camera much easier.

    macro rail
    macro rail

    More software changes have been incorporated to speed up and automate certain functions. For example, there are now three options that can be pre-selected to decide what happens at the end of the shot sequence – stay put, go back to park, or return to the first image. And there is now no need to go back to the park position to commence a shoot. I had put that into the software so that it would force a reset of the counter to allow for errors in positioning, however I have found the setup to be repeatable in this respect and so that precaution was unnecessary and just time consuming.

    All that remains is to make the control of the lights easier from the working position behind the camera, which entails a little more construction work and some wiring alterations. Then we will be done (perhaps!).

    By now you will have guessed that I get as much fun out of the construction of the rig as I do from taking pictures!

What’s it all about?

Here are my jottings about my photographic projects and activities. I have been working on a focus stacking macro photography rig. There are quite a few posts about that. In addition I write about other photographic activities as and when!

Archives

Category Specific RSS

Share


Warning: A non-numeric value encountered in /home/public/mhp_blog/wp-content/plugins/ultimate-social-media-icons/libs/sfsi_widget.php on line 238
RSS
EMAIL
Facebook
Google+
http://www.picsbymike.co.uk/mhp_blog/tag/focus-stacking/">
Twitter