Dave Bartlett : Photography : BA (Hons) : Learning Journal: Exercise 04 Shutter speeds

Wednesday, 8 February 2012

Exercise 4 revisited .. with a little help from Nelson

Although my initial efforts addressed the brief of producing a set of photographs that demonstrated the influence of shutter speed on movement of the subject, I felt that a more photogenic setting would have helped the cause. A trip up to London, initially to research some images for the ‘Contrasts‘ assignment and also to go to the World Wildlife Photographer of the Year exhibition at the Natural History Museum and the Taylor Wessing Portrait Prize exhibition at the National Portrait Gallery, gave me the chance to look at water movement again, this time using the fountains in Trafalgar Square. I wanted to get the movement going across the frame, so although I did shoot several sequences of the famous fountains, I spent most time with the squirting dolphins (at least, I think they are dolphins!). These gave a consistent and rapid water flow and also gave me the chance to get close with the minimum of disruption from tourists. I’ll write more about the two exhibitions and what I learnt there in a later blog after I have assimilated my thoughts on an awful lot of very different pictures.

I shot 12 images from 1/6000sec down to 0.3sec. I also observed the influence of shutter speed on aperture: the table below shows the relationship as the camera sought to maintain ‘correct’ exposure.

1/6000sec f/4 1/3000sec f/4 1/1500sec f/4

1/750sec f/4 1/350sec f/5.6 1/180sec f/8

1/90sec f/11 1/45sec f/16 1/20sec f/22

1/10sec f/22 1/6sec f/22 0.3sec f/22

This was a far more powerful water flow than in the weir pool exercise and 1/1500sec was the slowest shutter speed at which I would say that the water was frozen in motion. AT 1/180sec the water plume had lost all definition and this gradually declined further as the shutter speed decreased. At 1/20 sec individual droplets of water were streaked right across the frame. The images I took are shown below.

Technical details:

Canon 5D Mk II with 24-105mm f/4 L IS lens

82mm | ISO200

1/6000sec

1/3000sec

1/1500sec

1/750sec

1/350sec

1/180sec

1/90sec

1/45sec

1/20sec

1/10sec

1/6sec

0.3sec

Saturday, 4 February 2012

Exercise 4 : The Frame : Shutter speeds

Exercise 4 : Shutter speeds

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 exposure.

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.