MICROPLASTIC RESEARCH IN AGRICULTURE SOILS WITH DIGITAL CAMERAS
My spiritual experience through digital imaging of microplastics.
forest soil with organic and plastic materials combined
The goal of our experiment was to develop a digital-camera-based workflow that is portable and can operate cost-effectively to capture digital data from various sources in my country and abroad. My hope is that results will be adequate to discover further microplastic pollution around my area.
There is no universal harmonized term defining the dimensions of microplastics. I use the term of “microplastic” to determine small plastic particles, less than 0.1mm in diameter. Microplastics could be easily examined with laboratory microscopes already, but that machines are big, bulky, slow, and absolutely not cheap enough for my fieldwork. Furthermore, the acquisition of those special microscope equipments, the repair, and the possible replacements are impossible to come by in the middle of nowhere where I plan to collect data.
agriculture foil degradation into smaller particles
As I previously mentioned, the size of microplastics are not clarified properly and this is the reason why I should determine what magnification to use, that is suitable for my study. I decided to use an offline lens reversing ring on my existing Sigma 18-35 1.8 Art lens and fit it to my old Canon 650D APSC camera. This setup gave me a superb macro magnification with acceptable clarity and sharpness, what sigma lenses are about. Don’t forget this setup was cheap enough to fit into my smaller budget as well. This solution gave me 0.001 mm/pixel resolution, and believe me, I was shocked after checking my results on the big screen.
lens reversion converter for magnification
When you shoot in macro and micro sizes, average aperture setting becomes thinner than the human hair. I shot around f.18 and focus-stacked the images together to get sharp enough composite. To get sharp enough final composites I used 20 images for larger particles and 10 images for smaller particles. More images are necessary for bigger particles because they have more height. On the other hand, less images for the small ones based on their height and depth on the image.
plastic pipe particles mixed with sand rocks
I was playing with a focal length between 18mm and 24mm at different ISO settings to find the ideal values of coverage, brightness, and sharpness. I used a white card and corrected the color shift in post using the Capure One tether solutions.
My goal was to find plastic particles at sizes around 2mm to 250μm. I achieved acceptable results with the larger particles, but the small ones was not enough sharp and detailed for indentification and characterisation. My pattern recognition workflow has to fine tune in quality, detail and sharpness for further development.
I hope I managed to get a new feel of photography and could show you that with a minimal investment like 600-700$, creativity, and a lot of patience you can discover a breathtaking new world that is not only exciting and spectacular but also suitable for scientific purposes in the future.
real forest soil sample with organic and non-organic particles