In an earlier article we discussed aperture, shutter speed and ISO as they relate to the exposure triangle. This article looks to go into more detail about aperture priority and manual, two of your dSLR’s most popular manual shooting modes.
Aperture priority (A or Av)
As the name implies, aperture priority makes aperture the focus of your photo. You set your aperture and your camera will automatically set the shutter speed and ISO to give an optimally exposed image.
Why use aperture priority? Aperture priority allows you to focus on one aspect of the exposure triangle while your camera takes care of the other two. By focusing on aperture you are prioritizing the depth of field (DoF).
Why does DoF matter? DoF allows you to control how much of your image is in focus. In landscape photographs you typically want your entire image in focus so you’ll have an f-stop of f/8 or greater. Whereas in portrait photos you may chose to blur your background by creating a shallower depth of field. In this case a lower f-stop somewhere between f/2-f/5.6 would be suitable.
By choosing aperture priority you are essentially saying that you want to focus on your aperture / DoF as you have sufficient light to maintain a low ISO and there is nothing moving so the shutter speed also doesn’t matter.
Aperture Priority is one of the most commonly used settings on dSLR cameras so take the time to explore this mode.
In manual you have control of all three aspects of the exposure triangle. There are lots of ways to achieve an optimally exposed image but one or two aspects of the exposure triangle may be more important.
Why use manual? You’ll need to use manual if you want to control TWO or more components of your exposure triangle. You may need an aperture in a certain range to get adequate DoF while also having your shutter speed in a certain range to capture motion. Depending on the light you may also need to increase your ISO to keep the other two, more important values, in range. This is where manual provides you the ultimate control and small adjustments can make significant differences to your image. Just remember to keep an eye on your exposure compensation scale to ensure you have optimum exposure.
For example, in the seascape example below a 0.5-1 second shutter speed was the priority as it slows the ocean down but it doesn’t flatten the ocean into a cotton wool effect. An aperture that kept the entire image in focus was also important. The image was taken at sunset and the issue was too much light so keeping the ISO low was a win /win. The final image was an aperture of f/11, shutter speed of 0.5 seconds, and ISO 200.
While manual may seem overwhelming at first, the more time you spend using manual the sooner you’ll start to understand how aperture, shutter speed, and ISO settings can alter your final image.
While learning, make it a priority to spend some time with your camera in manual. Do it at a time where your photos aren’t time critical and make sure you review your images after each shot so that you can understand how any changes you made changed your image.