Aperture Priority

Manual mode can sound a little intimidating to many new camera users.  One way to make the transition from always shooting in automatic to manual is through aperture priority and shutter priority.  There are also occasions when you might decide to shoot in these modes even if you are comfortable with manual features.  

As a quick re-cap:

Shutter speed is how quickly your shutter opens when taking a photograph

ISO is how well your camera absorbs the available light

Aperture is how wide your shutter opens when taking a photograph and controls both the light and the depth of field in a photograph.  

Shutter Priority:

In shutter priority the camera gives you control over the shutter speed, but adjusts the ISO and aperture to get a correctly exposure photograph.  One time you might use this is if you wanted to achieve a 'movement effect' in you photograph.

In this photograph I wanted to capture the movement of the sign.  By adjusting my shutter speed to be slower than the spinning sign I created movement in the photograph.  I allowed the camera to adjust the aperture and ISO to correctly expose.  Other situations where you might use this would capturing water movement (waterfalls, taps, rain etc) and to create a sense of hurried movement (the classic is on a busy street or train station).

Aperture Priority:

I use aperture priority more often than shutter priority and it is often the easiest way to step from automatic to manual.  Aperture priorty allows you to set the aperature while the camera will adjust the ISO and shutter speed to correctly expose the picture.

Here, I was interested in capturing only the details of the XXX  so I set my aperture to f/XX.  The camera adjusted my shutter speed and ISO to correctly expose my picture.

In this photograph of the landscape I wanted the opposite to happen so I set the camera to a small aperture.

Remember to pay attention to what shutter speed the camera selects.  The camera will not know if you are using a tripod or have shaky hands. If the camera has selected a shutter speed that is too slow for you, you will need to adjust your aperture or ISO.  Which one you choose will depend on the photo. Mostly I try to adjust my ISO first and then aperture.

Aperture priority is pretty great.  In fact, for a long time I wondered why you would bother with manual mode at all.  Next week I'll tell you why.