Shutter Speed - Does it matter?

Shutter speed, does it matter?

In short - Yes.

Just to be clear the shutter speed is defined as the time that the sensor (or film for us oldies) is exposed to light. It is typically measured in fractions of a second but most cameras will have shutter speeds from 30 seconds to 1/2000 - some go to 1/4000 and even to 1/8000 - that is 1 eight thousands of a second! So the shutter is moving pretty darned fast!

A typical shutter speed progression is 1s, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500 and so on. Note how the time halves at each step. Each step, often referred to as a stop, lets light in for exactly half the time as the previous step. If you remember we discussed how the Aperture controls the amount of light we let in for each stop and that each time we stop down the lens aperture we halve the amount of light we let in. It becomes obvious there is a relationship between the two which is discussed in this article named: Understanding Reciprocity in Photography, details of the Aperture can be found here: Aperture - What is it and what does it do for us?

Note that many cameras are capable of shutter speeds in between those shown here and some can go up to shutter speeds of 1/8000 of a second.

If we control the aperture for creative reasons as well as controlling the amount of light that hits the sensor why should we be concerned about shutter speed?

There are three reasons why we want to control shutter speed, two of which are technical and one is creative. The latter we will only touch on briefly as it is somewhat outside of the scope of this article. The two technical reasons are to stop motion and eliminate the effects of camera shake. Whilst they are related to some extent there are differences between them. The creative reasons are if we deliberately wish to involve some form of motion blur in the image, be that from panning or intentional camera movement, however these are somewhat more advanced topics.


Stopping Motion

We are often photographing moving objects, such as our fish swimming in a tank. How many times have you taken a shot and thought "If only the fish wasn't blurred"? Often this is down to the fish moving whilst the shutter is open.

The following images demonstrate a sequence of shots that progressively stop motion. To eliminate all other variables the camera was setup on a tripod and triggered with a remote release. The lens was set to f8 for a suitably large DoF (we talked about this in here Aperture) and set to manual focus. It was then focussed at a given spot so that when the target passes it would be in focus. In order to allow the shutter speed to change and maintain a correct exposure the ISO was increased with each step. Constant studio lighting was used as there is a different relationship between flash or strobe lighting and shutter speed.

The target is simply a bio ball which is rolled down a shelf set on a slight slope. Again to re-iterate the images are perfectly focussed and are free from camera shake.

Equipment used for this demo:

• Nikon D610 camera
• Nikon 60mm AFS Micro lens
• Tripod
• Remote triggers
• Constant studio lighting
• Shelf
• Bio ball

All images were cropped to the same size with minor tweaking in lightroom. Exif data should be intact, but note the were exported at a pixel size of 1000 x 1000. However you should be able to click through to see them at a bigger size than shown here.

1/40 sec
https://farm9.staticflickr.com/8657/...1b3ffc36_z.jpgShutter_Speed_Demo_D610-7517 by SimplyDiscusPhoto, on Flickr

Note how blurred the ball is, it is hard to make out that it is in fact a ball.


1/100 sec
https://farm8.staticflickr.com/7446/...6f81845f_z.jpgShutter_Speed_Demo_D610-7521 by SimplyDiscusPhoto, on Flickr


Still blurred, but at least looks ball shaped!


1/200 sec
https://farm8.staticflickr.com/7415/...b7e201ab_z.jpgShutter_Speed_Demo_D610-7527 by SimplyDiscusPhoto, on Flickr

Beginning to see some detail, but still blurred.


1/320 sec
https://farm8.staticflickr.com/7400/...7403bffb_z.jpgShutter_Speed_Demo_D610-7533 by SimplyDiscusPhoto, on Flickr

More detail still, but still blurry.


1/500 sec
https://farm9.staticflickr.com/8624/...14c35950_z.jpgShutter_Speed_Demo_D610-7539 by SimplyDiscusPhoto, on Flickr

We can now begin to make out the structure of the ball, albeit some slight blurring! And this is with the shutter only being open for 1 five hundredths of a second way faster than a blink of an eye!


1/800 sec
https://farm8.staticflickr.com/7346/...c4b6b853_z.jpgShutter_Speed_Demo_D610-7544 by SimplyDiscusPhoto, on Flickr

Beginning to look sharp, still some blurring but very minor.


1/1250 sec
https://farm9.staticflickr.com/8567/...edca3c16_z.jpgShutter_Speed_Demo_D610-7549 by SimplyDiscusPhoto, on Flickr

The ball looks stationary, we have stopped motion.

What the above demonstrates is that in order to get sharp images of moving objects we have to make sure we are using a suitably high shutter speed. Even though we are talking about shorter and shorter durations that the shutter is open for, we refer to this as higher shutter speeds, the reality is that the actual shutter mechanism is moving at higher speeds!

The faster an object moves the higher the shutter speed needs to be to stop motion.

There are other factors which have an effect on motion blur, not least the distance between the camera and the object as well as the effective focal length of the lens. In general terms the further away the target object is the less motion blur shows, however the longer the effective focal length of the lens the more it shows motion blur.


Avoiding Camera Shake

Camera shake happens when the camera moves whilst taking a photograph. This results in blurred images. The simple fact of pressing the shutter release causes movement, even breathing does. It usually happens when the camera is being hand held rather than on a tripod, but even then under some circumstances it can happen. This guide will concentrate on using a camera hand held.

So how can we avoid camera shake?

There are two ways to avoid camera shake. These are technique and shutter speed. As this guide is discussing shutter speed I'll only discus technique briefly.


Technique

Technique can be defined as bracing and breathing. It is very similar to shooting a rifle. Simple things like tucking elbows in and having a stable base, with one foot in front of the other all help. As for breathing, take a breath, let out half of it and hold, then fire. If possible find something you can lean on or brace yourself against. Discussion on photos on techniques are discussed in detail in this thread: Techniques to better Photos.


Shutter Speed

The faster the shutter speed the less time the shutter is open, the less opportunity there is for camera shake.

The following images demonstrate this effect. The camera was hand held, and I used continuous studio lighting. The images have been cropped. Aperture was f8 and I used the ISO to allow different shutter speeds. The camera used was a Nikon D610 with the Nikkor 60mm AFS Micro lens. I chose the exciting target as it had writing on which shows sharpness, and therefore blurriness, well. The camera was set to auto focus. All images were taken once the camera acquired focus, in other words these are not deliberately blurred.

1/13 sec
https://farm8.staticflickr.com/7395/...bd6d5035_z.jpgShutter_Speed_Demo_D610-7551 by SimplyDiscusPhoto, on Flickr

As we can see from the above image, it is blurred, the whole of the image is blurred and we are unable to clearly make out the writing or any texture or detail on the table top. At 1/13th of a second the camera has moved whilst the shutter was open. It doesn't sound a long time but in photography terms it is considered to be a slow shutter speed and is often called a long exposure.

1/200 sec
https://farm8.staticflickr.com/7378/...38ef36c7_z.jpgShutter_Speed_Demo_D610-7552 by SimplyDiscusPhoto, on Flickr

The above image is nicely sharp showing clear writing and the detail and texture in the table top. This was taken at 1/200th of a second, much faster than the previous image. This minimises any camera shake being recorded.

However this doesn't mean that a shutter speed of 1/200 will always avoid camera shake as that depends on the users technique and the effective focal length of the lens in use. In simple terms the longer the lens the faster the shutter speed needs to be. In the good old days of film (I still use this btw) there was a rule of thumb that stated the minimum shutter speed should be the reciprocal of the focal length. What this means is that if you are using a lens with an effective focal length 100mm then a shutter speed of 1/100 would be a good start point. With longer lenses we can quickly see that we need faster shutter speeds, e.g. using a lens with an effective focal length of 300mm our shutter speed would be 1/300.

The above rule of thumb is a decent starting point and works well with most lenses and cameras.

Many lenses and some cameras now come with some form of vibration reduction system, in Canon speak this is referred to as IS (Image stabilisation), in Nikon speak VR (Vibration Reduction) with Sigma lenses using OS (Optical Stability) and Tamron VC (Vibration Control). Sony lenses do not have any form of VR as this is built into the camera body. These systems work quite well and allow the user to use much lower shutter speeds, however they will not stop action, for that fast shutter speeds are the order of the day.


Creative Motion Blur

There are basically three types of creative motion blur. These are the use of panning, and no that isn't for gold!, intentional camera movement and long exposures. As stated previously this is a fairly advanced topic so the explanation here is necessarily brief!


Panning

This is when the moving object is followed with the camera whilst using a slowish shutter speed (sometimes called dragging the shutter). The camera "pan" is kept at the same relative speed as the moving object. The effects of this is that the object itself is in sharp focus but the background is blurred giving a sense of movement. Many photographs at car race tracks are taken using this technique.

Intentional Camera Movement

This is when the camera is moved in a deliberate fashion with the intention of creating an abstract image. Done well it can produce wonderful results, done poorly and it will not come across well.

Long Exposures

We would use this technique almost always with the camera mounted on a sturdy tripod. It is often used to blur movement in water and clouds to give a somewhat dreamy look, yet maintaining the detail in the surroundings which will not be moving. The following image shows this
https://farm8.staticflickr.com/7381/...ed56c961_b.jpg
Arboretum Waterfall revised by rickztahone, on Flickr
Notice that the water fromt he waterfall looks somewhat "milky" in nature. The slowed down shutter speed help create this effect. Waterfalls and landscape shots are typical subjects for long exposures, but there are quite a few other reasons to employ them. One of which is to eliminate people from your shots. Long exposures will tend to only take in stationary objects. The longer the exposure stays open, the more chance there is of completely eliminating people or moving subjects from your shot.
This a sample of a shot taken at the Chinese Theater in Hollywood. You can obviously see people in this shot, but a lot less shown than there actually was. Had the shutter speed been longer, it would have almost completely take care of all the people:
https://farm6.staticflickr.com/5497/...c750a514_b.jpg
Chinese Theater Pano by rickztahone, on Flickr

Here is another example of long exposure. Notice the trees seem motionless while the stars have created a trail across the sky. This is due to the camera being stationary, and in a dark environment the longer (lower number) shutter speed allows the sensor to open for a number of seconds and capture as much light and movement as it can. Since to our eyes the stars are constantly moving as the earth rotates, with an open shutter, they create trails across the sky. Like most all long exposure photos, a sturdy tripod is a must.
http://i27.photobucket.com/albums/c1...tartrails1.jpg

If you have any questions about this please feel free to ask and we'll do our best to answer them.