G'Day Possums - some more birdie shots from the wilds of Dumfries and Galloway. This time, I visited the area known as Caerlaverock (pronounced: Car-lav-er-ock) an area on the estuary of the River Nith famous for its castle (another day perhaps) and its Wetland Centre www.wwt.org.uk/wetland-centres… . There are many hides and habitats for wetland birds and I was fortunate to be able to snap some wildlife I had not come across before as well as some avian behaviours that were novel to me. Unfortunately, the day was overcast with poor light lacking in contrast; towards the end of the visit we had continuous heavy rain, making shots even more difficult. But, with the Canon 5D Mark III fitted with the 100-400 zoom plus 1.4 extender, I did capture some useful shots.

First off, Caerlaverock is known for its swans, especially whooper swans (Cygnus cygnus). Swans mate for life and this pair is probably such a couple. Whoopers are instantly recognizable by their bright yellow tapering to black bills. The more common mute swan has an orange/black bill. Swans including whoopers like to feed from the bottom of the ponds and so up turn to partially submerge. Once finished they right themselves and shake off the excess water. I was lucky to capture an almost perfect "angel wings" pose from one such, next image. If you zoom in you can see all the water droplets on the swan's head, soon displaced by further vigorous shaking.


  


The mute swan (Cygnus olor) is by far the most common swan in the UK and photographs of them abound on DA. Here's one that is a bit different: it is a male (from the black knob at the head of the bill), it has the characteristic orange bill, and it is busking - that is the term given to the "pose" whereby its wings are neither folded back on to its body nor fully extended, but are held in that semi-open position while the bird paddles through the water. It is a rather attractive display, one that is seen more in paintings and other depictions of swans than in photographs. The reasons for this display are probably to do with drying the wings and displaying to females.





Wherever you look at Caerlaverock there are ducks, big ones, small ones, brown ones, black ones, gentle souls and those, like the following male tufted duck, in battleship pose. The tufted duck (Aythya fuligula) has, normally, a characteristic tuft of feathers sprouting from the back of the head. Regrettably, this male with its striking black and white plumage chose not to paddle in an appropriate direction for me to capture that, preferring this slightly aggressive advance, possibly to ward off others intent on the female tufted ducks. There is just a hint of the tuft in the female shot, but more importantly, the plumage is a sort of gray-brown composite with an almost speckled appearance at the top of the bill. Sexual dimorphism is the technical term (I think) for different plumage in the males and females. Note the bills are the same - a light grey with a hint of blue and a black tip.


  


Another favourite species, but one I had never seen before, is the wigeon (Anas penelope). Wigeon have breeding grounds in Iceland and other northerly places, and fly back to winter here in October, so we were seeing, probably, some recent arrivals. The first shot below shows a young male, and the second a male following a female with possible designs on her virtue. Males have that white patch on their side, while females do not. The plumage for the males in these shots , however, is a bit odd, the males normally having a grey back with almost no speckling on the wings. What we are seeing here, probably, is an example of what is known as "eclipse" plumage. In common with most birds, ducks moult their feathers in late summer and grow fresh plumage. Once feathers are moulted, the ducks cannot fly until new feathers grow. So, male ducks in particular are more vulnerable to predators - sparrowhawks and falcons. Evolution has come up with a protective mechanism - a sort of camouflage plumage (if looking female can be said to be camouflage) known as eclipse plumage. This then morphs into the full male plumage after a few weeks. I think that is what we are seeing here with some of the grey plumage on the back appearing while the eclipse plumage disappears.


 

 


We caught sight of the following species quietly feeding on one of the smaller ponds. It is a gadwell duck (Anas strepera). Small and inconspicuous in a larger mixed flock gadwells just go about their business not getting in anyone's road. From a distance they do not appear to be very interesting, but the long lens shows a highly intricate patterned plumage. There is often a white splash to the plumage towards the rear, but bird books comment that this is often hidden, as here. At the other end of the activity and plumage spectrum we have the shoveler (Anas clypeata). Unmistakable plumage, a huge bill for scooping up pond life and a slightly menacing air characterise this bird.



  


Finally, for this journal, I'm returning to swans with these two shots. On a slightly out of the way pond we found this male mute swan guarding two almost fully grown young. A small group of wigeon provide some infantry protection. The young are probably about 18 months old, swans fully maturing at about two years. The cob (the adult male) will protect its young until they are fully mature; even though avian predators are unlikely to seize such a large bird as prey, foxes could take a young swan.





This last shot I hope will be seen as a pretense at an art work with the youngsters dabbling in the rain. And who can forget Danny Kay singing: "There once was an ugly duckling with feathers all stubby and brown..." 








That's all for now folks! Hope you enjoyed the show.

David aka Okavanga

Continuing disabling mobility problems have meant that I've been stuck inside with little opportunity to photograph outside. So, I've been messing around at my work station with filters to see if I can make anything useful by way of images. In particular, I dug out my polarising filters. If light passes through a polarising filter it becomes polarised, that is the transmitted light vibrates in only one plane. This so-called polarised light has properties that are not seen by the naked eye compared to ordinary light. For example, the glare of reflected light from a glass or water surface is all but eliminated. Most sun glasses (shades to our US cousins) have polarising filters in the glass and thereby help reduce glare. While messing about with a couple of these filters I remembered a fact about computer monitor screens that not a lot of people know: provided the screen is in a flat screen monitor (a TFT monitor) the light given off by the screen is polarised! If you are looking at this text on a TFT monitor the light entering your eye is polarised, as if it had already passed through a pair of Ray-Bans. You can prove this by taking a polarising filter (normally such are called circular polarising filters), looking through it and turning the polarising ring. Suddenly, the view goes dark as the polariser cuts out the polarised light from the screen.  Weird or what? 

Now, we can use this set-up - a source of polarised light - the monitor screen - and the polarising filter - attached to a camera lens - to illustrate another phenomenon that gives some spectacular photographic images. The phenomenon is known as birefringence (pronounced "bi - re - frin - gence"). Here's an image of my vari-focal lenses, taped to my monitor screen with its light coming through, photographed with a polariser filter on the lens of the camera. Look at the weird coloured patches that show up. So, when I wear those glasses the polarised light entering my eyes when looking at the screen is coming though in different colors. I'm not aware of that but  that's what's happening. Most spectacle lenses that are made form polycarbonate plastics will exhibit this property, coloured polarised light. And the scientific name for this is birefringence.






Let's look at another example. This is a measuring jug again made of polycarbonate plastic. I've adjusted the polarising filter on the lens to make the screen black, thereby showing the colours from birefringence to full advantage. You can think of the phenomenon as similar to the effect of passing normal light through a prism whereby the light gets split into its component colours - the colours of the rainbow. The difference here is that you need polarised light to pass through the substance - plastic here - and another polarising filter to see the effect. The colours are basically those of the rainbow, but aligned in a different and apparently random order. What causes this effect? The substance through which the polarised light passes needs to have its constituent molecules aligned in a specific direction rather than randomly dispersed, such a substance being known as anisotropic. When this type of substance is subject to stress then the molecules that were aligned in one direction get pushed out of alignment and polarised light is diffracted to different degrees by those areas that are out of alignment, splitting it into different frequencies and hence colours.





If you look up photography and birefringence on the Web, you will almost certainly come across images like the following: cutlery looking metallic and full of bright colour. In fact, the cutlery is made of plastic - polystyrene in this case - and the metallic sheen is part of the effect of birefringence on the surface of the plastic.  I've used an etched glass for the holder to illustrate that ordinary glass does not usually show birefringent effects, the glass and the etching have mostly no hint of colour, except at the very bottom.





Occasionally, you do come across a glass object that shows the effect, as in this example, one of those decorative glass paperweights, this one full of air bubbles. Why some glass objects can show the effect while others don't, may be because of the process of annealing. To be as strong as can be, glass objects need to cool down very slowly so that the glass sets in the most energetically favourable way. If parts cool down too quickly they cause stress within the structure and I think it is that stress that the birefringence is showing up. But, from a photographic view so much the better!





There are creative possibilities if you make you own objects out of a material that exhibits birefringence. The next few shots show the possibilities using a small piece (ca. 6 inch square) piece of thin cellophane which I crumpled up into a ball and then let relax into a crinkled shape. The resulting colours can be intense and varied and create a 3D jewel like effect, especially upon a black background.





You might strike lucky and the crinkled plastic might resemble some thing real, such as a heart as seen below. Normally, however, an abstract image is the result.





This final example shows that you can employ your photo-editing software to good effect in order to alter the gamut of colours. The first of the three shots shows the original birefringent image and the two other shots show the effect of altering the hue of the colours using, in this instance, the appropriate tool in The Gimp software.


    


Technical points: My Canon 5D Mark III camera was mounted on a tripod and fitted with the standard 24-105 mm zoom lens which in turn was fitted with a circular polarising filter.  The aperture was set to f/22 and the distances from the screen were approximately 2 feet in order to ensure full depth of focus for the objects being photographed. Exposure times were 2 - 4 seconds and ISO values were 100-400.


Note that this Journal is part of my continuing explorations into what I have called Extra-Visible Imaging, much of the previous explorations involving Infrared Photography, and Full Spectrum Photography, see:
 

Festive Greetings with Extra-Visible ImagingFestive Greetings with Extra-Visible Imaging.
A Merry Christmas and Happy New Year to Everyone.
Christmas trees are up, decorations hung, turkeys ordered, booze bought, presents wrapped, cats napped, candles lit, and carols sung – just another day chez Okavanga! But merry Yuletide Greetings to one and all – I trust everyone will enjoy themselves in these dark mid-Winter days  - except of course those in the Southern Hemisphere who will be celebrating mid-Summer, - oh and then those who of other religious persuasions who probably have their own feast and holy days, - ah now there are many who are not religious at all and therefore may feel excluded – I had better include you, and then there are … oh never mind – Happy Late December to the World.
Some may know that I recently took over the running of the Infrared-Club. https://infrared-club.deviantart.com/ What with the populari   The Okavanga Effect v2The infrared images below were taken only a few seconds apart and, with only one difference between them, they have been treated in post-processing in exactly the same way. Yet that single difference has caused the very substantial change in the character, colours, and tonality of the images, with bright yellow areas dominating the visual space. It is this that I call, rather immodestly, the Okavanga Effect.
                         
The images have the following in common. A Canon 40D camera converted to full spectrum capabilities was used, fitted with an R72 infrared filter. The camera was tripod mounted. A custom white balance was employed, this having been obtained by shooting with the R72 filter in place against a standard grey card. Other than the R72 filter, no other filter was used. Light conditions were identical with the shots  and  fIRe - Innovative Infrared:iconinfrared-club::iconinfrared-club::iconinfrared-club::iconinfrared-club::iconinfrared-club:
The advent of digital photography and the rise of powerful digital editing techniques has allowed infrared photography (IR photography) to move on from the traditional film based images that relied on the Woods Effect ("white" foliage) and the lack of scattering of IR light ("black" skies and long distance clarity). The relatively simple software processing of channel swapping, while still a useful technique, is giving way to more innovative techniques such as colour renditions, and highly structured contrast images. Infrared photographers recognise that there are no limits on how to interpret and develop images captured by sensors sensitive to IR light. Here are five innovative images that all come from basic IR captures taken with my converted Canon 40D camera. The principal software used for development was the Google/Nik suite, particularly Silver Efex Pro 2. The purpose of these images


Enough for now - plenty to think about and to try if you have a TFT monitor, a polarising filter and suitable plastic objects.

Many Thanks for viewing.

Cheers

David aka Okavanga