Recently in Scientific photography Category

I thought it was about time I got back to writing and looking at scientific photography on my blog so I here is a recent photograph of poppy seeds. Yes well exciting! Actually poppy seeds I realized after taking photographs of bread with ultraviolet fluorescence looked interesting so I used photomacrography to get closer and the shapes on the surface are hexagonal.

Heaxgons are not uncommon in nature from the shells of some prehistoric creatures, to eyes of moths and other insects, shapes of honeycomb and wasps nests and inside our eyes with the corneal endothelium. More on hexagons to follow this piece.

For information on the mathematics of hexagons go to http://www.mathopenref.com/hexagon.html

The lights I use are standard Blacklight fluorescent tubes I (the University anyway) have a Kaiser copy stand with 2 foot tubes which can be replaced with Blacklight ones.

Philips produce these blacklight tubes and also screw fitting bulbs. They are used in Discos and other places so should be readily available.

The lights are set at 45° to the subject with a 2B filter in front of the camera so only the fluorescence, light emitted, is recorded.

As most of my are subjects are still I have used Fuji Velvia which gives greater colour saturation but a faster film can be used or a digital camera. Exposure at 100 ASA, f/5.6 - f/8 is of the order of a second can be longer or shorter. The exposure is dependent on the light source as usual but of more significance is the amount of light emitted by the subject a dyed fluorescent object e.g. paper, pencils and bought items are strong emitters, some rocks are very strong others weak, lichens are weak, eggs are in the middle. Testing and adjusting exposure is necessary. Can also use a flash with a UV filter over the flash for example an 18B or 18A glass filter.

For further information download my 'Guide to infrared and ultraviolet photography' (750Kb Mb pdf file) from my Publications page more about principles than a simple how to do it.

Weblink - Medical and Scientific Photography Online resource http://msp.rmit.edu.au/

When we take photographs are we changing what we see to suit our view or extraction of reality? A photograph is capturing what we see we capture not the reality but the reality as we see or interpret it the photographer is both observer and interpreter. Heisenberg's Uncertainty principle could equally be applied to photography.

We also can photograph what we cannot see with the naked eye to capture in our memory photography is beyond that as we can capture different chunks of time that we see in continuous motion. We capture with infrared and ultraviolet and the light emissions of subjects due to light or other radiation. As we use more and more digital capture devices so the time has shortened between the moment of capture and seeing what we have captured. We like video cameramen before us have become slaves not to our viewfinder and imagination but to our LCD screens.

Photographers had to wait for gratification till after processing and printing. We waited in anticipation or dread to see the final result; now we can see it as soon as the file has saved onto disk and know we have what we want or not and either keep it or delete it. The negative does not reach the neg sleeve or the cutting room floor instead it is deleted or downloaded then awaits its fate in hard drive failure or some eventual digital graveyard along with betamax and laser disks.

Going closer to a subject we see what we would otherwise never see unless extremely shortsighted the unseen made visible has been an enduring chase for photographers looking at things through different lenses. This is still the goal of photographers whatever they photograph to reveal their personal vision of the world to the world. In many ways the only need is for capture and print to reveal all the use of further editing might be seen as superfluous or the task undertaken to reveal even more from the perfect print in the darkroom to the PhotoShop editors mouse but at what point does that artistic or scientific extraction or abstraction become the reality or further and further removed from "reality".

If proof were ever needed, we are in danger of editing out the truth behind the natural beauty of the photographic image. But, how much alteration is too much? How much reinterpretation can we undertake before we are distorting through the unreality of our personal perceptions.

"The sensitive photographic film is the true retina of the scientists . . . . for it possesses all the properties which science could want; it faithfully preserves images which deposit themselves upon it, and reproduces and multiplies them indefinitely on request; in the radiative spectrum (electromagnetic spectrum) it covers a range more than double that which the eye can perceive and soon perhaps will cover it all; finally it takes advantage of the admirable property which allows the accumulation of events, and whereas our retina erases all impressions more than a tenth of a second old, the photographic retina preserves them and accumulates them over a practically limitless time." P.C.Janssen 1888

Photography using a borescope, endoscope or arthroscope requires a specialised lens or attachment to connect to an ordinary lens.

These lenses are expensive, if you can even find them for sale now, as they are specialist and can be obtained from manufacturers of endoscopy equipment for example Olympus equipment supplied by KeyMed in UK.

The important aspect is to make sure there is a firm attachment between scope and lens, even if makeshift, otherwise the image will be off centre within the frame. The nearest thing since the takeover of video in the operating theatre are videocouplers for example that sold by Edmund Optics which uses a C-Mount, they also sell borescope for inspection work.

High speed photography at its best requires great accuracy in timing which part of the splash is recorded. However, with a very simple disposable camera or digital camera with an integral flash it is possible to take photographs of splashes or using a video camera extract individual frames each of 1/25th of a second to see the processes involved.

Useful websites include:

http://www.rit.edu/~andpph/exhibit-splashes.html
http://courses.ncssm.edu/hsi/class2000/splashes
http://courses.ncssm.edu/hsi/splashes

One of the problems with scientific photography has been the need to do one if not more tests of exposure on a film. One method has been to use black and white film for the test (carefully recording exposure s used on paper), process, check exposure then take colour photographs. This whole process can be shortened with a digital camera.

Not only that but a digital camera also records the lens and camera data including exposure and aperture used which is embedded into the file format. This helps in refining exposure but also can be used in image management software to detail length of exposure, aperture which seem to be so popular in photographic magazines.

Images can be taken, techniques can be tried without having to wait for feedback after processing hours or days later enabling quicker feedback. There is really now no excuse for not using scientific photographic techniques in science teaching or communication.