The objective of this
exercise was to use different shutter speeds and observe the shutter speeds at
which an object was 'frozen' or showed movement.
The camera was set on Tv mode – shutter priority – such that the
aperture was adjusted with each change in shutter speed to maintain the same
The original plan was to
visit a fountain in one of the local parks and photograph the water, but the –9C
overnight temperature soon caused that to be cancelled ! I wanted to work with water, so the local
River Blackwater was the next best thing – with only Saturdays to shoot, I felt
I needed to get weaving with the exercises and maintain what has been a
reasonable momentum with the course so far.
The stretch of river I had
in mind has a spillway and small weir pool that gives water movement at two different
speeds - the very fast, smooth movement down the spillway and the chaotic turbulence
of the pool. The camera was mounted on a
tripod and a view down the spillway framed to fill most of the image. Photographs were taken from
1/8000sec to 1/3sec and resultant images compared for movement of a) the fast
and smooth water of the spillway and b) the slower white water of the pool.
The fastest shutter speeds
of 1/8000sec down to 1/350sec gave very similar images, with no indication of
movement in either fast or slow water.
Close examination of the fast water at 1/180sec (using 100% view on
screen) showed the first signs of a blurring in the pattern of flow, but the
turbulent, slower water, was still sharply focused. At 1/90sec water at both speeds was blurred
and I found this was the most pleasing image, giving a nice dynamic sense of
the flow of the stream. At 1/45, 1/20,
1/10, 1/6 and 1/3sec blurring increased proportionally and none of these
shutter speeds gave a pleasing image – there was just too much movement.
It would have been
nicer to select a more interesting subject for this exercise,
but the weir pool served its purpose in less than ideal conditions. I was surprised that the first signs of
failure to freeze the movement occurred at 1/180sec as I had expected it happen
at a faster shutter speed given the apparently rapid rate of water flow. I plan to come back to this exercise at a later
date and re-shoot a more colourful subject with a greater distance of travel.
Canon 5D Mk II with 24-105mm f/4 L IS
|Location for shoot|
|1/90sec - my preferred option|
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