Exercise: Focal lengths

Take a sequence of photographs, all aimed in the same direction, at different focal lengths.

These photographs were taken in Hyde Park of a sculpture by Anish Kapoor. It was a miserable, wet, dull day - quite dark, despite being only one o'clock in the afternoon.

Focal length 18.0mm, f/3.5, shutter speed 1/125s.
In this photograph the foreground is emphasised, the line of trees shows the depth in the scene and leads the eye down to the sculpture. The tree line in the background is quite thin - it highlights the sculpture.

Focal length 63.0mm, f/5.0, shutter speed 1/125s
As the focal length increases it seems natural to move the horizon further up the picture to create some depth. The perspective in the line of trees on the right has become quite compressed.




Focal length 250.0mm, f/6.3, shutter speed 1/125s.
At this length the different elements in the landscape - the foreground, the lake, the trees in the background, have become almost like flat strips - almost abstract. There is very little impression of depth compared with the same scene shot at 18.0mm.

Focal lengths and different viewpoints

Take two photographs of the same scene, one using a telephoto lens, one with a wide-angle. Compare the differences between the resulting images.

Focal length 250.0mm; f/11; 1/125s

Focal lenght 18.0mm; f/14; 1/125s

With the telephoto lens, the perspective is compressed - the distance between the building and the trees behind looks minimal. The building itself is flattened - it's difficult to see that it is actually round, and this has made the roof look like a slightly odd fit. The colours are slightly washed-out - particularly in the sky.

With the wide-angle lens, the distances between the different elements in the photograph - the foreground, t he building and the trees behind - are much more obvious. The building is clearly round - emphasised by the straight line of the fence in front of it. The roof fits. The sky is a deep blue (the two photographs were taken about a minute apart). I was able to use a slightly smaller aperture for this shot and it's given the picture a richness which the telephoto shot lacks.

This was a really interesting exercise - I can see it having an immediate impact on my photography and I might not reach for the telephoto lens by default in future.

Exercise: Shutter speeds

With the camera on a tripod and fixed in front of something that moves continuously across your view, make a series of exposures from the fastest shutter speed on your camera to a very slow one.

These photographs are of a weir on the river Cam; the day was bright and sunny but the weir was out of the sunlight apart from the bottom left corner; all the photographs were taken at a focal length of 43mm. From this viewpoint I could see two sources of water falling - the one on the right is at much higher pressure than that at the back.

Shutter speed 1/2s, f29: at this speed, the flow on the right is completely blurred - barely recognisable as running water. It could be cloud. The other source, however, is less affected by the long exposure, though it appears more opaque than it actually is. The bottom left area of the scene is very over-exposed at this shutter speed.

Shutter speed 1/5s, f29: more detailing is appearing in the mass of foam from the right although it is still very impressionistic, and there is more detail to be seen under the flow at the back - although it is still less transparent than it was to the naked eye. The bottom left is still over-exposed, but there is still more detail here.

Shutter speed 1/6s, f29: it's now possible to see fairly clearly the detail behind the flow at the back, though the left flow is still blurred, and the bottom left is still over-exposed.

Shutter speed 1/8s, f29: there's a lot more detail in the burnt-out bottom left corner at this shutter speed; in addition, in the mass of white foam from the right the rapids are beginning to take shape.

Shutter speed 1/20s, f20: much more detail here; the white foam is starting to look quite murky.

Shutter speed 1\50s, f13: this is now quite recognisable as fast-flowing water - even in the bottom left corner. The green reflection which has appeared as quite a bright light at slower shutter speeds is diffused at this speed.

Shutter speed 1/100s, f9.0: still some blurring - especially in the foreground - but much more definition is appearing; the intermittant nature of the flow at the back is clearer; the green reflection top right has nearly disappeared.

Shutter speed 1/200s, f7.1: still some blurring - the drops of water visible in the top third of the photograph are tear-shaped and the flow at the back is clearly streaked; however, the foam at the front is now fairly lacy compared the earlier photographs. The green reflection is barely visible at this speed.

Shutter speed 1/400s, f5.0: movement in this photograph is still not frozen absolutely sharply - the highlights at the back are still streaking; however, you can see a lot more detail in the foaming water in the bottom two-thirds of the picture - right down to individual bubbles in the water.

Shutter speed 1/1000s, f4.5: at this speed the camera can't cope with the light conditions - the aperture is not sufficient to light up the top third of the picture. However, there is nice lot of detail in the bottom two-thirds, with drops of water frozen in the air.

Preparation for Assignment 1: Contrasts

Winter, work and weather have conspired to prevent me taking any photographs for a few days, so I've been thinking instead about how to approach the first assignment: Contrasts. Initially I wasn't particularly inspired by the assignments – I couldn't really get past the idea of taking pictures of things; photographing something thick or something thin, something large or something small, something smooth or something rough. But then I was leafing through some old photos and came across this one, taken last Autumn in Stratford-Upon-Avon: (Canon 350d; 210mm; 1/30s; f18.0) Looking at this photograph I thought that it was not simply a photograph of something undeniably hard (decorative paving under a bridge), but actually communicated a sense of hardness. So I spend some time thinking about what qualities in the photograph were responsible for this impression.
Contrast: there is very little subtlety in the contrast in this photograph; the highlights and lowlights are extreme, and there isn't much tonal contrast between them.
Depth of field: the aperture was reasonable small, so focus is fairly sharp over the whole photograph.
Light: because this photograph was taken in the early afternoon on a bright day the light is quite hard, and the shadows are sharp and strong. Subject: the photograph is full of sharp angles and jagged lines – there are no smooth edges.
Once I'd started to think like this it became much easier to think about how I could communicate some of the other abstract qualities listed:
Rounded/curved To promote a sense of roundness or curves I will try to maximise the tonal range in the photograph, so that the contrast between the highlights and shadows isn't as extreme. I will take the photograph with an aperture tending towards the wider end of the scale, and shoot in soft light.
Thin/sharp/pointed/narrow For these qualities, I will experiment with narrow apertures and strong light (though depending on the subject I may also try a wide aperture to contrast the subject in focus with a blurred background).
Soft/rough As with rounded/curved, to communicate softness I will try to minimise contrast in the photograph, photograph in soft light and with a wide aperture.
Small This one has been quite interesting to think about – I've been looking at techniques for faking miniaturisation, which contain some tips such as taking an elevated viewpoint, and blurring out the foreground and background. I'm not going to try fake miniaturisation for this assignment, but I'll use those tips.

Large

This link leads to a photo by Stephen Maclaren which shows a way of suggesting largeness - without simply positioning an object next to something small. The foreshortening caused by the low viewpoint (and handy attitude of the dog) gives the impression of a dog the size of the tower of Big Ben. [Photo from http://www.museumoflondon.org.uk/NR/rdonlyres/9CA3C5DF-0F52-408E-85F7-A0A86962E457/0/LARGE_LSP_StephenMaclaren.jpg]
For this assignment I will make things as easy as possible for myself by photographing subjects which I clearly relevant to the quality – I won't be trying to take something hard and trying to make it look soft. But I suppose that would be a challenge.