A = Control
As visual communicators, there is a lot of things we need to know. Among the top of the list is #1 – the mind’s eye goes to light and bright and #2 – the mind’s eye goes to sharpness. The focus on the subject and the depth of focus around that subject (also known as depth of field) is often what determines what lens I’m going to shoot with and the aperture desired. This all has to do with #2, grabbing the attention of the mind’s eye. The rest of the elements in the photograph tell the story, but subject is the same as a noun in a sentence and it has to be sharp. It’s what the whole photo is all about and we use sharpness to take your to the subject first thing. With that said, my camera’s are nearly always in Aperture Priority, were I control the DoF with the aperture and the camera sets the shutter speed. I want to control where the mind’s eye goes in the photo so I set the Aperture. This is the first reason I feel Aperture Priority is a photographer’s best friend.
The second reason Aperture Priority is your best friend is speed. The camera’s computer can come up and recommend the best shutter speed much faster than we can permitting us to keep our attention on the subject. Of course, you must use exposure compensation to use exposure to express the emotion you want to convey. And with that input from you the camera is lightning fast. Keep in mind that in Aperture Priority, the shutter speeds are stepless. If you don’t know that term, you need to learn it because it puts accuracy with speed in your back pocket. Sure, there are times when Manual Exposure modes might help you, but I’ve never understood why folks spend thousands of dollars on a computer just to turn it all off. Every time you can remove any variable in making a photograph so you only concentrate on the subject, your photographs will improve. It is up to you what tools work best for your photography in this pursuit, but keep an open mind. You might find that giving exposure control to your camera actually gives you more control over the photograph.