Exercise 4 – Shutter Speeds
I’ve set the camera up on a tripod and selected a small waterfall from a lake overflow sluice. I’ve composed the image to include part of the stream the water falls into as well as the fall itself as I‘ve feel this in an important part of the image to also demonstrate the effects of shutter speed on an image. I’ve set the camera to shutter priority so that aperture will be set by the camera as I slow the shutter speed from a fast starting place of 1/4000 second for the starting image.
I’ve resized all images to 800 pixels along their longest legth to help reduce file sizes being used for these exercises
Image 1 – 1/4000 second
I’m using a Nikon 28-105mm f/3.5-4.5 lens and the widest aperture limit had resulted in an underexposed image since the aperture couldn’t open any wider in response to the very fast shutter speed I’ve set. I’ve adjusted the exposure in Photoshop, as I’ll have to in some of the next images I’ll present in this set. At this speed the speed of the water is effectively frozen, which is apparent in the water droplets caught in mid-air
Image 2 – 1/3200 second
The water in the image is frozen static still at this shutter speed
Image 3 – 1/2000 second
The water in theimage remains frozen static still at this shutter speed
Image 4 – 1/600 second
The water in the image remains frozen still at this shutter speed, water droplets in mid air still appear static
Image 5 – 1/500 second
The water remains frozen still at this shutter speed, water droplets in mid air still appear static
Image 6 – 1/250 second
There is a hint of movement in the water; the water droplets compared to the previous images appear to have changed shape slightly.
Image 7 – 1/160 second
There is slightly more movement in the water at this shutter speed.
Image 8 – 1/60 second
The camera has set the aperture to a smaller size at f/5 to correctly expose the image as the shutter is opened longer. Movement in the image is starting to become more obvious as some water droplets have streaks and the water in the fall is staring to become smoother.
Image 9 – 1/40 second
The camera has amended the exposure again, this time to f/8 letting less light through the smaller aperture to attempt to maintain the correct exposure at the slower shutter speed. Movement in the water now is much greater; water droplets have longer movement trails and the falling water looking even smoother now.
Image 10 – 1/3 second
The aperture is now further reduced to f/25 to counter the longer shutter opening and the water is now beginning to take on a smoother and milky effect, particularly noticeable on the right of the image.
Image 11 – 0.80 second
The aperture again is made smaller at f/29 and the water is now beginning to look over exposed at this shutter speed of 0.80 seconds. The water at the bottom of the fall now appears as a complete blur
Image 12 – 1 second
At an exposure of 1 second the camera is no longer able to reduce the aperture past the lens maximum of f/29 and now the image is starting to become visibly over exposed
Slowest shutter speed before movement is visible
Based upon the images I’ve taken, the shutter speed at which movement becomes visible occurs between Image 5 with a shutter speed at 1/500th second and Image 6 at 1/250th second
Exercise Learnings
a) In shutter priority the camera will automatically set the aperture to attempt to obtain the correct exposure
b) In addition to learning a) there will be a maximum shutter speed for which the camera is able to select the widest aperture to correctly expose the image as there will also be a minimum shutter speed for which the camera is able to select the narrowest aperture. This will be impacted by lens minimum and maximum apertures, level of lighting in the scene being photographed
c) Subject to the speed of movement of the subject being photographed, there will be a specific shutter speed for threshold at which movement of the subject can be detected in the image
d) Creative use of shutter speed can be used when creating images to display movement or even to blur movement
e) If the image visualised requires such a slow shutter speed that would likely result in an image being over-exposed because the lens is unable to use a narrower aperture then alternate methods could be used to reduce the light reaching the sensor. For example a polarising filter will reduce the amount of light reaching the sensor as can graduated filters or combinations of these. Searching Google reveals that there are lens screw on filters that allow an exposure reduction of up to 10 stops. Using these options, looking at Image 11, I could further increase the shutter speed to allow more movement of the water to be captured without overexposing the final image, as has started to happen in image 12
f) There will be a link between shutter speed, aperture and filters light blocking abilities (measured as stops and/or 1/3 stops). I have seen in the earlier exercises that creative use of aperture and depth of fields can allow the photographer to direct the image viewer to an element of the photographer’s choosing. Therefore the photographer through a series of calculations could determine the required light blocking required (measured as stops) should they wish to use a specific aperture and shutter speed combination. This would then determine the number of stops required of the filter, or filters in combination, required to create the image required and also ensure its correctly exposed.
Further Reflections and Experimentation
- In googleing images of water, waterfalls, rivers, sea and waves etc in many cases there appears as a desire from photographers to capture water movement to the degree that the water appears milky, in effect a greater exaggeration of the images I started to create above using slower shutter speeds. As I found from image 12 onwards, light blocking filters are required to slow the shutter speed further and maintain exposure levels
- Consider investment and experimentation with filters
- Identify calculation charts confirming aperture / shutter speed / light stopping filter combinations. For example “Lee’s” filter website confirms shutter speed durations for specific apertures when using its 10 stop filter, known as the Big Stopper
- This creative use of shutter speeds can also be used for creating movement in clouds and smoothing the effect of bodies of water such as lakes / ponds / seas where it may be impacted by wind and tide etc. This is an interesting area to experiment in.
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