Shutter Priority Mode

Shutter Priority Mode

Aperture settings allow great control over depth of field but shutter speed is sometimes more important and can make or break an image.

My first camera was Manual exposure only. The layout of controls led me to use it in the spirit of Shutter Priority. I'll explain. The shutter speed was set on a dial on the top plate. Generally, and we're talking about starting out, a shutter speed was chosen in order to avoid camera shake spoiling the image. The instructions also leant towards this. The metering button would be pressed and the idea was to align a neddle with a zero in the viewfinder, most easily achieved by adjusting the aperture ring. If the lens couldn't go any wider, then the shutter speed would be adjusted to suit.

One reason Shutter Priority was less popular in automatic exposure cameras was because it required more complex linkages between camera and lens in order for the camera to control the aperture. It was easier to produce a shutter that was controlled in response to the aperture set. Lenses at the time were much simpler in terms of what they communicated to the camera. A sliding contact linked to the aperture control adjusted an electrical signal. This could be used to adjust the electronics controlling the shutter. To control the aperture, extra mechanical (or electrical) linkages were required and correspondingly new lenses. The same issue meant Program mode was a rarity. Fully electronic linkages developed but that still meant redesigned lenses. For a long while now we've taken this situation for granted.



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Different people have different ways of working. Shutter Priority is, on the face of it, ideally suited to anything movement based, be that Formula One or wildlife. However, I tend to stick with Aperture Priority and just turn the control wheel until I get a shutter speed I want. It is, in effect, the same as using the same control wheel to scan through the shutter speed list. For example, choosing 1/2000 for a flypast of a Typhoon then 1/250 for a Spitfire in order to get some propeller blur. I guess how I get there is immaterial, it's the shutter speed that's important in terms of final results that matters. In many ways aperture is less of an issue in that the difference between f/4 and f/8 at 500 mm isn't going to have much effect on depth of field in the way it would at 50 mm. Faster speeds will help enormously especially as the subjects photographed with long lenses tend to be the ones where high shutter speeds are most useful. So you would tend to favour setting a fast shutter speed and not worry about aperture.



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Landscapes with flowing water are another area here shutter speed can have a big effect, from freezing movement to total blur. Take your choice.

Choosing Shutter Priority in order to keep a high enough speed to avoid camera movement (and indeed subject movement) spoiling an image is fine but you may 'run out' of corresponding apertures. Once you get to your lens's maximum aperture it won't get any wider so you'll run into underexposure. That's the aspect of shutter priority that keeps me using aperture priority in a lot of situations.

There is a proviso, and I don't know how many current cameras this applies to, but some can be set to override the set shutter speed to avoid exposure issues. Canon, for example, called this Safety Shift. So you wouldn't get underexposure but you need to keep an eye on the shutter speed as it may drop too low o stop action. The opposite is also true where the camera can increase shutter speed if overexposure is a risk.



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Even if you rarely or never use Shutter Priority remember that for some images shutter speed is the important consideration.

Next time I'll look at Program mode.


All text and images © Keith Rowley 2021