Describe the difference between AF-S and AF-C and give scenarios for each.

• A. AF-C locks focus on press and release; ideal for still subjects
• B. AF-S continuously adjusts focus as the subject moves
• C. AF-S locks focus on press and release; ideal for still subjects
• D. AF-C locks focus when you half-press; ideal for macro

Answer: (C)

Focus behavior is what separates AF-S from AF-C. AF-S (single servo) focuses once when you half-press the shutter and then locks that focus distance, so anything after that point won’t drift if the subject isn’t moving. That makes it ideal for still subjects or scenes where the distance to the subject won’t change before you shoot—think posed portraits, still life, or landscapes where you aren’t tracking motion.

AF-C (continuous servo) keeps adjusting focus as the subject moves while you maintain the half-press. It’s designed for moving subjects, so you can track action and keep the subject sharp even as distance changes—like a running athlete, a bird in flight, or a child playing.

In practice, you’d use AF-S for still subjects and AF-C for moving subjects. The scenario examples help illustrate: a stationary portrait or product shot benefits from AF-S, while sports or wildlife photography benefits from AF-C.