How do I choose between aperture-priority, shutter-priority, and manual exposure?

Start by asking: Which setting do I need to keep under my control for this shot?

Use this quick selection chart:

• Aperture-priority (often A or Av): Choose this when you want to set the aperture, including for its depth-of-field effect. The camera selects shutter speed. [S1]
• Shutter-priority (often S or Tv): Choose this when you want to set shutter speed. The camera adjusts aperture. [S2]
• Manual (often M): Choose this when you want to set both aperture and shutter speed yourself. Check other settings, especially whether ISO is automatic. [S3]

For example, if the background’s appearance is your main concern, start with aperture-priority. If you need to choose a particular shutter speed, try shutter-priority. If you want to hold both aperture and shutter speed at chosen values, consider Manual. These are starting points, not rules: the right choice depends on your intended result and how your camera is configured.

No. In aperture-priority, you select the f-number and the camera selects a shutter speed for the exposure. [S1] This makes the mode a useful starting point when you want to choose the aperture for its depth-of-field effect while leaving shutter speed to the camera.

Still, pay attention to the shutter speed it selects: it remains part of the exposure, and you may decide it doesn’t suit your picture. Canon’s explanation supports this general mode description, but exact controls and behavior can differ by camera. Check your model’s instructions if its display or controls don’t match.

Try shutter-priority when your first decision is shutter speed. On the Canon EOS Rebel T7, Tv is shutter-priority AE, and the camera adjusts aperture to maintain exposure. [S2]

The camera has limits on how far it can adjust. Canon says that on this model, if it reaches its aperture limit, it may not be able to achieve exposure at the selected shutter speed. Its guidance is to adjust shutter speed or ISO. [S2] This is model-specific, not a guarantee of identical behavior on other cameras. If you see an exposure warning, consult your camera’s instructions and consider which setting you can change without losing the intended result.

Use Manual when you want to choose both aperture and shutter speed instead of asking the camera to select one of them. But the mode name alone does not tell you whether ISO is also under your control. Canon’s EOS R specifications list Auto ISO ranges in Manual as well as in other exposure modes. That shows Auto ISO can be available in Manual on that particular camera; it does not establish the same behavior for other models. [S3]

Worked choice: Suppose you want to choose the aperture but are willing to let the camera select shutter speed. Start with aperture-priority. If you instead need to choose a particular shutter speed, try shutter-priority and check the camera’s exposure indication. If you want to choose both aperture and shutter speed, try Manual and separately check whether ISO is fixed or automatic. These examples help you select a mode; they do not guarantee a particular exposure result.

A quick routine is to name the setting that matters most, choose the matching mode, check what the camera is adjusting, and review the exposure information. For Manual, verify the ISO configuration too. If your camera behaves differently from these descriptions, follow its model-specific instructions.