Bud Black wrote:
Okay, here is one that should be easy for you hogs. What is the difference between choosing aperture or shutter preferred? And which is better? I am using a Canon G9X which features both choices. For instance, if I want to shoot a subject and have the complete screen in sharp focus, or if I want to aim at a subject and have it in sharp focus but blur.out the foreground and background. This may seem like a basic question, but humor me as I.am but a novice.
No auto exposure mode is "better". They each have their uses, depending upon what you're shooting and how you want the images to look.
Aperture Priority mode (Av in Canon cameras) is the one to use when depth of field is important for a particular shot.... either great depth of field, sharp from near to far with a small aperture... or shallow depth of field to blur down a background and make a subject stand out by using a large aperture.
Shutter Priority mode (Tv in Canon cameras) might be what you want to control how subject movement is rendered in images... fast shutter speeds to best freeze all movement OR slow shutter speeds to allow some deliberate motion blur and depict action in a still photo.
Other auto exposure modes include:
Program mode (P), where both shutter speed and aperture selection are left to the camera can be useful when none of the above matters and you need to work very quickly.
Manual + Auto ISO is actually another form of auto exposure... which can be useful when you want to control both shutter speed and aperture for the above reasons, yet still need auto exposure.
Flash is yet another mode.... It can be "fill flash" where it merely supplements ambient lighting conditions. Or it can be "full flash" where it's the primary, dominant or only light source. In the latter case, the flash itself acts like a faster shutter speed to freeze subject movement (most flash will give effect similar to 1/720 shutter speed) REGARDLESS of what shutter speed is set on the camera. The distance flash can reach is controlled primarily by aperture and ISO changes. Much flash is now done using a form of auto exposure, but there is also fully manual flash.
Some folks will try to tell you that pure manual mode is the best way to shoot... but that's simply not true. Sure, it's nice to lock down all the exposure factors precisely, when it's possible to do so. However, depending upon what you're shooting, ambient conditions and techniques you're using, some form of auto exposure can be the only way to "get the shot". So it really pays to know how to use all the different modes. There really is no such thing as a single "best" exposure mode. Buy the book "Understanding Exposure" by Bryan Peterson. Read it. Study it.