Most of the subjects we photograph are by reflected light. That is, a light source illuminates a subject which, in turn, reflects light from its surface. We then bring those reflected light rays into focus on a digital imaging sensor (or film emulsion) which records the image.
So most of our images are reflections and the nature of these reflections – contrasty, dark, light and so on – is largely subject dependant. For example, you wouldn’t expect to obtain a full tonal range when photographing a black billiard ball or get a specular highlight from a hessian bag.
The lighting controls we use which modify the light before it strikes the subject are really about how we create shadows on and around the subject. The modelling effect of the shadows is one of the most important controls that allow us to reproduce three-dimensional subjects on two-dimensional media and still manage to convey to the viewer the subject’s three-dimensional nature.
This modelling effect works in conjunction with perspective control and our previous visual experience to generate the three-dimensional effect on what is essentially a two-dimensional medium. For example, imagine a wide-angle lens positioned close to an obliquely lit flower with a mountain range in the distance. The angular light creates form and texture within the petals of the flower while the mountains look quite small. Previous experience will tell us that flowers are not larger than mountains and so we assume that the photographer has placed the viewer up-close-and-personal to the flower, exaggerating the perspective. Without a previous knowledge of flowers and mountains, this type of image, if transmitted into space, would be a poor choice as it could distort an alien’s perspective of what it really looks like here.
Using what I call ‘secondary reflections’ can be another way of creating interesting images from sometimes mundane subjects. Virtually everything in the universe has, or leaves behind, a signature. Photographing the virtual image or signature created by a subject can create some thought provoking images.
However, there are some issues that you often have to contend with when creating these types of images especially when you include a real and a virtual image in the same composition. To demonstrate a virtual image, have a look at the inverted, diminished, virtual image in the wine glass above.
The image is inverted because it is seen upside down. It is diminished because it is much smaller than the subject itself. It’s also virtual in that it is brought to an imaginary focal point a few centimetres in front of the glass. You could place a focusing screen at any distance from the glass and the image will not be rendered focused on it. This type of virtual image is created by transmission. The only way of getting both – the real image of the wine glass and the virtual image within in it – into focus on the sensor of your camera is to focus on the glass then ensure the depth-of-field extends far enough in front of the glass to render the virtual image sharp as well, or vice-versa.
Photographing the virtual image of clouds produced by reflection in a puddle of water will create a similar situation. the lilies in the foreground were only two metres from the lens while the reflection of the clouds in the sky – being the virtual image – were in focus at infinity. The lens was focused a little past two metres, but the lens aperture was stopped down to f16.5.
Another approach would be to use a longer lens positioned farther away from the pond. If the lens wasn’t too long, the pond and virtual image may just fall into focus at infinity.
Either of these techniques could increase the depth-of-field so that the clouds appeared in focus as well. Had the clouds not been there, it wouldn’t have mattered because without the texture of the clouds you wouldn’t be able to determine if a bald blue sky was sharply focused or not. For my previous article on the use of a polarising filter see the August 2011 issue of ProPhoto.