Tag Archives: Exposure tips

The Canon Powershot G1X Digital Point-and-Shoot With SLR control. Billed by Canon as the “Highest Image Quality Powershot Digital Camera”

Getting sharpness right…

It’s not just about the right camera. It is also about technique and knowing the best way to set up your shot. Getting the right shutter speed takes a little knowledge when you are starting from scratch. Here are some pointers to help you make choices about shutter speed.

Why set your own shutter speed?

Getting full control of your camera is an important aspect of gaining creative control over the outcome of your photographs. Despite what the manufacturers say, you can only achieve so much by messing around with their ‘modes’. Capturing pictures using camera modes other than the basic photographic modes (ISO, aperture, shutter speed) is going to give you a programmed result. In other words ‘modes’ are what some boffin back at the lab has formulated as ‘about right’ for the average photos people take. But, you are not average are you? You want to produce the shot your way. So gaining control over your shutter speed is important.

The long and short of it

Shutter speed gives us creative control in a number of ways. A very shallow depth of field will give great bokeh in the background. But it is difficult to create on a bright day unless you have a fast shutter speed (to reduce the incoming light). Bokeh is created by a wide aperture. A wide aperture lets a lot of light in. If the shutter is open too long the photograph will be overexposed. So a shorter shutter speed is required.

Shutter speed also controls movement blur. If you are taking a photo of a moving object a relatively long shutter speed will create greater blur (example 1/15th sec). A very short shutter speed will tend to freeze the action preventing blur (example 1/500th second).

Sharpness counts

Starting to control your shutter speed is often about finding the best shutter speed that you can handle for a sharp result. So what is the lowest hand held shutter speed you can apply?

Actually, in practical terms, the slowest hand-held shutter speed is reliant on a number of factors…

• Physical fitness: If you are not strong enough for using your camera weight it is more difficult to hold it steady. Regular practice with your camera will help you build muscles to steady your hand and therefore shoot at lower shutter speeds.
• Focal length: Longer focal lengths tend to need higher shutter speeds. As you shoot further into the distance the angle of movement seen at the point of focus is more exaggerated.
• Optical stabilisation: If your lens is optically stabilised this means it will compensate for the tiny movements of your hands. This compensation will help you to reduce hand shake and therefore give you potentially longer shutter speeds.
• The picture you want to create: Obviously, the picture you want to produce is dependent on how much blur you want in it. So if you want no blur (for the sharpest result) you want a fast shutter speed.
• The amount of light: Brighter light allows you to have a shorter shutter speed. Knowing when to use a tripod instead of hand-held is the crucial issue here. Most people simply give up if a low shutter speed demands a tripod… For the accomplished photographer many of the best shots are found in low light situations. So shutter speed control is of crucial importance – as important as using a tripod at the right time.

Rule of thumb

Those factors aside here is a rule of thumb. In practice most people do not shoot with a steady enough hand to produce sharp hand-held shots below 1/60th second. Of course, optical stabilisation on the lens will help you get longer shutter speeds. But even then a practical limit of 1/30th of a second is about as low as you can go and be sharp. That is not a shutter speed I would suggest you work with regularly when hand-held.

Best guide to shutter speed

The shutter speed you need to work to is often related to the focal length you are working with. There is a reasonable rule that can help you get a good guide to picking the best shutter speed for your focal length. It is said that the longest shutter speed you can use hand-held for a lens or zoom setting is:

1 divided by the Focal length times 1.5

So, if your lens is a normal lens at 50mm it will have an effective lowest hand-held shutter speed of 1/(50 x 1.5) or 1/75. The nearest (rounded up) setting on your camera is likely to be 1/80th second.

If you are working at 200mm then, 1/(200 x 1.5) or 1/300th of a second will be your lowest working shutter speed. The nearest setting on most cameras will be 1/320th second.

These apply if you are not using optical stabilisation. You can of course work one or maybe two stops faster if you are using stabilisation. You will need to check that figure against your lens specification. Most optical stabilisation systems will give you between one and two stops extra control.

Shutter speed standard

shutter speed is standardized on a 2:1 scale. When you open the aperture on single aperture stop and at the same time reduce shutter speed by a single step the result will be an identical exposure. This table shows the shutter stop standard steps…

• 1/2000 sec
• 1/1000 sec
• 1/500 sec
• 1/250 sec
• 1/125 sec
• 1/60 sec
• 1/30 sec
• 1/15 sec
• 1/8 sec
• 1/4 sec
• 1/2 sec
• 1 sec

The scale extends up above these figures to very high shutter speeds. Up to date DSLRs may allow have shutter speeds of less than 1/5000ths of a second. Very fast indeed. While at the other end cameras will allow long shutter speeds of up to 30 seconds in manual modes (M mode; or Manual) and longer in “bulb mode”.

Each of the steps in the table above will be equal to a change of one stop of light up or down. A change of one stop of light will double the amount of light entering the camera.

As one stop of light is quite a large amount, cameras have become more sophisticated. Most are now marked off with thirds of a stop for ISO, aperture and shutter speed. So your calculations can be quite precise and lie between these values in the table above.

You can read more about stops of light here: Definition: f number; f stop; Stop

Doing it right

Gaining control over your camera is of importance if you want to become a creative master of its full potential. Learning about shutter speed and other aspects of exposure are critical to learning that control. You can have great fun creating bokeh and controlling movement blur. At the same time you can remove that other type of blur – ugly hand-held shake-blur.

Please leave questions and issues for us to discuss if you want to take this further…

By Damon Guy (author and Photokonnexion editor)

Damon Guy (Netkonnexion)

Damon is a writer-photog and editor of this site. He has run some major websites, a computing department and a digital image library. He started out as a trained teacher and now runs training for digital photographers.
See also: Editors ‘Bio’.

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