technique - When to use shutter priority instead of aperture priority?

Under what circumstances would you use aperture priority vs. shutter priority and vice-versa?

I typically don’t use shutter priority (ever) and favor aperture priority to try to get a max aperture with the thinking that I’ll get more light and a better low light shot. But after getting almost all my shots being blurry and the help of a couple questions posted here I learned I should use faster shutter speeds to get clear shots.

What my question boils down to is me trying to get a firmer understanding when to use one over the other, and why.

Thanks all.

Answer

Shutter priority (Tv) gets used for a couple good reasons

You want to control the shutter speed (obviously) and don't care about the aperture. You'd use this to have creative control over the shutter speed which mostly involves motion blur. Some techniques that use this are 'dragging the shutter' with flash to create motion streaks and a final 'flash' to stop the motion. Or 'dragging the shutter' while tracking action where you move the camera to follow a subject and keep it sharp while blurring the surroundings.

You also use Tv with flash when you want to lock in a certain shutter speed (to avoid camera shake) while allowing the camera to control the aperture (and sometimes ISO). Useful when you're, say, shooting with a 85mm lens and you know you want to have at least 1/100th shutter speed to not blur the subject and let the flash/aperture handle the rest.