Tuesday, 23 February 2010

Exercise 4 and 5

What:The brief of this exercise was to explore the interaction of moving objects at various shutter speeds. The exercise was broken down into two parts. The first part was to lock the camera off on a tripod to prevent movement and then photograph at varying shutter speeds (from 1 second to 1/4000 of a second) moving objects as it went through the frame. The second part of the exercise was to again photograph at varying shutter speeds but this time the camera would be held and panned with the moving object to keep it in the frame.
Where: At the side of the A1 road just outside Dunbar. The road at this point slows to a roundabout.
When: Just after 10' O'clock. The weather was dry but cold with a bright low sun and scattered clouds
How: Camera Settings were set to at speed priority and at ISO 100. There was still too much light to allow the camera to properly set the aperture, so I used a Neutral Density filter, this filter allows the reduction of light into the sensor without affecting the colours of the objects. This filter was an ND8, which meant that it reduced the light by 8 stops. The ISO was stepped up as necessary to allow the speed and aperture to be set as required. The camera was set on a tripod to stop any movement and I photographed the cars as they came into the frame.
I then moved slightly down the road to the edge of the roundabout, so that I would have time to see the cars as they came towards me which would allow me to frame them in the viewfinder and the take a photograph as the car passed, panning with the camera as I did.
I used an 18-55 kit lens, set at 31mm. The photos have had no software manipulation, just a straight conversion from RAW to JPG.
I have decided to do a slideshow of what I photographed today, as putting them all one after another on this blog would make it difficult to see. What I have done is upload them to my flickr page and put them under a collection called OCA in subsets. All the exercise 4 photographs can be found here

Again I noticed the reciprocation between shutter speed and aperture as I set the camera up and the requirement to change the “light speed” of the ISO to allow me to keep the shutter speed and aperture within the expected specifications
When I checked the cameras screen I quickly noticed that the cars were just not appearing in the photographs where the shutter speed was set at about 1 second, all that was captured was a very light blurring within the frame. The cars were invisible to the sensor as they were in and out of the frame before the shutter closed again.
I had an expectation that the vehicles would not start to show their form until the shutter speed was at 1/160, but I was surprised to see that vehicle shapes were recognisable at 1/20. The text on the sides of vans was recognisable at 1/125.
I prefer photograph 062 as this still shows movement as the wheels are blurred but the car is clearly shown and this gives a sense of speed. Once the photographs shutter speeds go above 1/320 the cars are completely frozen and this doesn't fully allow you to see that the car was a moving object.
In the panning photographs, I am drawn in two different directions, while I like the photograph 0116 as the car is sharp and clear and the blurring of the wheels and the background show that the car was moving at speed even though the photograph was taken at 1/30 as I had assumed that this shutter speed would be too slow to give a clear sharp image.
I am also drawn to the more abstract shapes and colour created in the slower shutter speed photos where I also panned the camera as shown in 0147 and 0149.I was pleasantly surprised to see that in the panning photos that the cars were very recognisable down to quite a slow shutter speed. I had through that speed

I have learned that shutter speeds can be used to freeze action to a complete standstill, or the shutter speed can be used to create the impression of movement, especially when used with the panning movement.
I also learned that if I have the requirement to reduce the amount of light coming into the sensor and that I cannot get the camera and lens to "go slower" that the neutral density filter can be used. The filter just stops down the light by the filter number, i.e. a ND2 filter will have the effect of stopping down the light by 2 stops, a ND4 filter will stop down light by 4 stops, and a ND8 filter will stop down light by 8 stops. These filters can be combined to reduce light by their combined numbers, ND2+ ND4 equals a 6 stop deduction.

Just a side note on todays exercise; always keep some form of identification on you as you may be stopped and questioned. I had someone stop their car on the side of the road, walk back to where I was standing and demanded to know why I was photographing his car, he was quite bolshy and kept asking why, even after I gave him a careful explanation.
Funnily he never identified himself and he was quite pushy even when I showed him my student card and the exercise text.

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