Shutter speed, Movement & Light: My examples

Below are some examples of how I have used shutter speed for creative effect in the past, along with annotations in view of my previous post on this topic. Following on from this, I have included some very basic images from one of my travels with my camera.

f5, 1.3sec, ISO100, 18mm.
I'm sick of seeing this, but its one of the best (read: luckiest) images I've ever shot (May 2011). It is an obvious example of a light trail, which always look better in low light.

f7.1, 3 sec, ISO400, 18mm.
I consider this as part of the same series at the above. I called this series 'Urban Colour', due to the fact I originally over-cooked the images using Nikon's own processing software that came with the camera. I was equally as overjoyed when I took this, due to the fact the light trail of the tram in motion stretches exactly from one end of the frame to the other.

f20, 5.1 sec, ISO100, 26mm.

Two things to mention here: the extremely narrow aperture allowed for over a 5 second exposure and a nice sharp image. The best thing for night shots is the use of a tripod and a nice narrow aperture. This was bonfire night last year: I set my tripod up, stuck my camera on self-timer, and covered the lens with a piece of thick black card. The shutter was on Bulb mode, which allowed for a completely manual exposure, which starts by exposing the black card, and removing this only when I felt the explosion was n view. I then replaced the card and ended the exposure. This is meant to be more accurate with a remote shutter.

f8, 1/250th, ISO100, 18mm.
I want to compare this (shot during the perfect light of a crisp January morning this year) with the same scene (shot at night) to show how the shutter speed varies from day to night; how slowing the camera down is the major way of accommodating poor light conditions.

f10, 15sec, ISO100, 18mm.
The fact I have used the same ISO setting in both images makes it easier to compare. You can see from the shutter used here that it is a good twelve stops slower than that of the one shot in daylight (if I may use this term), based on the fact that one turn of the dial in Shutter Priority constitutes a third of a stop. Of course, had I increased the ISO (and subsequently compromised the sharpness of the image), this would have allowed for a much faster speed (each time the ISO is doubled, it allows a whole stop of light onto the camera's sensor).

Below are a few snapshots of passing cars I shot to demonstrate how much movement is recorded at various shutter speeds.

1/20th second.

1/10th second.

1/5th second.

The above images are shot a 1/3rd of a stop apart, all at f22, using Shutter Priority.

Shutter Speed, Long Exposure & Movement

If Aperture refers to how wide the camera's aperture diaphragm is opened, then shutter speed is the amount of time it is open in order to give a correct exposure. Put very simply, when we have a wide aperture, the shutter does not need to be open for as long to ensure the image sensor (made more sensitive by increasing the ISO setting) receives adequate light to expose the chosen scene. On the other hand, when a narrow aperture is chosen, the shutter needs to be open for longer to allow the light to enter. A popular diagram to explain how long the shutter needs to stay open at different aperture settings is shown below. This is generally regarded an easy 'at-a-glance' guide, and usually found in many a beginners booklet and introductory website (I've tried to select the most basic-looking one, but there are many different versions).

You can tell from this basic bar graph that, the larger the aperture (lower the number), the faster the speed of the shutter (which is to say it doesn't need to be open for as long). Also, at the top, it gives a guide for ho much depth of field is given by choosing said aperture value. And the bottom shows the amount of 'motion blur' that occurs at different shutter speeds.

Motion Blur

When we speak about motion blur, initially we think of it as a negative occurrence as a result of choosing too slow a shutter speed. It is said that the point at which this blur is most likely to occur is anything slower than 1/60th, although I have taken perfectly decent architecture (and even landscape) images at 1/40th: it depends on how steady you are at shooting handheld. However, in some shooting situations we actually desire this blur for creative effect to show movement in an image. So, as illustrated in the table above: Motion blur is to Shutter Speed what Depth of Field is to Aperture, in that this is the element that determines the creative effect. In the diagram below, you can see how much movement is present at various shutter speeds:

The above diagram shows the effects of using different shutter speeds from 1 whole second (slow; gives the water a milky texture) to 1/800th of a second (fast; practically a 'snapshot' of the water).

The shutter speed/exposure time allows the photographer to be as creative as he/she wants. I like to think of it as playing with light and time itself. When you have the shutter open for a certain amount of time, anything that happens in the scene- any light that happens to be falling upon objects (be they moving or stationary) is recorded by the image sensor. The resulting image will always be a snapshot, but what this snapshot contains is determined by how long the shutter is open.