Unusual or striking images can be used gently, as a good way to generate discussion, or form the centrepiece of a more involved enquiry-based learning exercise. In this small exhibition of some recent images, we have withheld details of the scale and nature of the subjects to help this process along. Some brief details can be found below.
James Collett (STRI University of Hertfordshire)
Details:Canon EOS 5D Mark II : Olympus 50 mm f/3.5 Macro : 1/25 s ISO 100
Comments:Fluid optics is one of my personal favourite subjects and here we see some nice examples. The medium is honey and on the left is an oil lens and on the right an air bubble acting as both a mirror and a lens. Counter intuitively looking at the image, the bright almost metallic central portion of the bubble is the lens and the golden rim is the mirror.
Details:Canon EOS 5D Mark II : Sigma 105 mm Macro : f/2.8 1/3200 s ISO 400
Comments:This pattern of water ripples was certainly well known to Leonardo da Vinci. This set occurred downstream in the convergence of shallow streams from opposite sides of a notch in Hertford weir. The colours reflect the base of the weir and its vegetation.
Details:Canon EOS 5D Mark II : Canon 180 mm Macro : f/18 1/125 s ISO 1600
Comments:This vivid set of interference colours comes from a small portion of a vertical soap film. The film has to be illuminated and viewed obliquely and the disturbed fringes evolve rapidly so there is a limitation on the depth of field possible in images of this kind.
Details:Canon EOS 5D Mark II : Sigma 105 mm Macro : f/5 1/500 s ISO 1000
Comments:A single spark from a small (12.5 cm diameter) grinding wheel. The spin rate of such a wheel might typically be a few thousand revolutions per minute. The visual impression of the sparks is never as complex as this particular still demonstrates.
Details:Canon EOS 5D Mark II : Sigma 105 mm Macro : f/22 1/250 s ISO 3200
Comments:Photographs of sparks often use long exposures to capture a fluid-like cascade but it is interesting to try a short exposure too to illuminate individual trajectories and evidence of rotation.
Details:Canon EOS 5D Mark II : Sigma 105 mm Macro : f/4.5 1/200 s ISO 125
Comments:An interesting effect that I first saw illustrated in the beautiful book Color and Light in Nature by David Lynch and William Livingston. This particular example of multicoloured lens flare was generated by a spider’s web in my father’s shed but you can see the same effect in scratches in glass, water caustics and strongly illuminated wing veins on insects.
Details:Canon EOS 5D Mark II : Canon 24-70 mm : f/16 1/80 s ISO 320
Comments:We tend to think of cracks as occurring in very dry layers but this nice pattern reminiscent of a stained glass window occurred in a depression in a clay-rich sand dune. The ground was soft enough to take the impressions of animal feet that had crossed the polygonal plates.
Details:Canon EOS 5D Mark II : Olympus 50 mm f/3.5 Macro : 1/30 s ISO 160
Comments:To recreate a similar ‘wet’ set of cracks in the kitchen, I used a mixture of oil, cream and ink left to dry naturally in a shallow tray. The layer is still soft to the touch but the crack pattern is well developed – an individual crack here is about a millimetre long.
Details:Canon EOS 5D Mark II : Olympus 50 mm f/3.5 Macro : 1/10 s ISO 800
Comments:This image is dominated by large numbers of oil lenses in a thin film of honey. The dramatic lighting is achieved by placing a scrunched-up tissue between the light source and the film.
Details:Canon EOS 5D Mark II : Olympus 50 mm f/3.5 Macro : 1/6 s ISO 320
Comments:These fringes were drawn to my attention by Ken Henman, the Principal Technical Officer in our laboratories. You simply look down a polished aluminium tube at a featureless light source, in this case a light box. The camera struggles to accommodate the dynamic range of the fringes but does add a rather mystical feel.
Details:Canon EOS 5D Mark II : Olympus 50 mm f/3.5 Macro : 1 s ISO 320
Comments:By moving the camera off-axis, you can get a better impression of the beautiful colours visible through the tube.
Details:Canon EOS 5D Mark II : Olympus 50 mm f/3.5 Macro : 2.5 s ISO 200
Comments:The ‘Great Red Spot’ in this image is about 1 cm across. This lovely fluid pattern in a solid came to light a few years ago when my father turned a composite plastic tube in a lathe to clean up its rather dirty cylindrical surface.
The framed photographs may be purchased at a special conference rate and taken away at the end of the conference on Friday 21st August. The cost ‘to go’ is £35 for the smaller 25 x 25 and 25 x 30 prints and £40 for the larger 25 x 37 prints. They can be mailed but at significantly extra cost. The prints were made with a Durst Lambda printer onto archival quality Kodak Endura photographic paper.
If you require unmounted prints, wish to use the images in publications, or have a scientific imaging request please contact Jim directly at j.l.collett@herts.ac.uk.