Can I keep a moving subject in auto focus when shooting a movie? (EOS 70D)

Article ID: ART142077 | Date published: 05/13/2015 | Date last updated: 11/04/2015


Can I keep a moving subject in auto focus when shooting a movie? (EOS 70D)


Using the Movie Servo AF function will allow you to keep a moving subject in auto focus. During movie shooting, the camera focuses the subject continuously. The default setting is [Enable].
Icons used on this page:
[ ]: Movie shooting tab 1 / [ ]: Custom Functions Tab / <>: Movie shooting switch / < >: Live View shooting switch / [ ]: Servo AF / <>: Flash button / <>: Playback button

Setting [Movie Servo AF]

1. Set the cameras power switch to <ON>.

2. Set the Live View shooting/ Movie shooting switch to <>.

3. Press the <MENU> button to display the menu screen.

4. Select [Movie Servo AF] from the [ ] tab, then press <>.

5. Select [Enable], then press <>.

When Movie Servo AF is set to [Enable]:
  • The camera focuses the subject continuously even when you are not pressing the shutter button halfway.
  • Since this drives the lens continuously, it will consume battery power and shorten the movie shooting time
  • With certain lenses, the lens operation noise during focusing may be recorded. To reduce the recording of the lens operation noise, use a commercially-available external microphone. With EF-S18- 55mm f/3.5-5.6 IS STM or EF-S18-135mm f/3.5-5.6 IS STM lens, the lens operation noise is less prone to be recorded.
  • If you want to set the lens focus mode switch to <MF> during Movie Servo AF, first set the Live View shooting/Movie shooting switch to <>.
  • If you want to keep the focus at a specific point or you do not want the lens operation noise to be recorded, you can temporarily stop Movie Servo AF as follows. When you stop Movie Servo AF, the AF point will turn gray. When you perform the same steps below, Movie Servo AF will resume.
- Tap the [ ] icon on the lower left of the screen.
- Press the < > button.
- Under [ C.Fn III-4: Custom controls], if a button is assigned with [AF stop], you can pause the Movie Servo AF while holding down that button. When you let go of the button, Movie Servo AF will resume.
  • While Movie Servo AF is paused, pressing the <MENU> or < > button, changing the AF method, or other operation will have Movie Servo AF resume when you resume movie shooting.
When [Disable] is set:
  • Press the shutter button halfway (only before you start movie shooting) or press the <AF-ON> button to focus.
Cautions When [Movie Servo AF] is Set to [Enable]
  • Movie Servo AF will pause during zooming or magnified view.
  • Movie Servo AF will not work during movie digital zooming.
  • During movie shooting, if a subject approaches or moves away or if the camera is moved vertically or horizontally (panning), the recorded movie image may momentarily expand or contract (change in image magnification).
Shooting Conditions that Make Focusing Difficult
  • A fast-moving subject approaching or moving away from the camera.
  • A subject moving at a close distance in front of the camera.
  • Low-contrast subjects such as the blue sky, solid-color flat surfaces or when highlight or shadow details are lost.
  • Subjects in low light.
  • Stripes and other patterns where there is contrast only in the horizontal direction.
  • Subjects with repetitive patterns (skyscraper windows, computer keyboards, etc.).
  • Fine lines and subject outlines.
  • Under a light source whose brightness, color, or pattern keeps changing.
  • Night scenes or points of light.
  • Under fluorescent or LED light sources and when the image flickers.
  • Extremely small subjects.
  • Subjects at the edge of the picture.
  • Subjects strongly reflecting light.
  • The AF point covers near and distant subjects (such as an animal in a cage).
  • Subjects that keep moving within the AF point and cannot keep still due to camera shake or subject blur.
  • A subject approaching or moving away from the camera.
  • Autofocusing while the subject is very far out of focus.
  • Soft focus effect is applied with a soft focus lens.
  • A special effect filter is used.
  • Noise (spots, banding, etc.) appears on the screen during AF.



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