How to Use Movie Digital Zoom on a Canon EOS 70D
Using digital zoom on your Canon EOS 70D enables you to capture a movie using a smaller area of the image sensor than normal. The result is a movie that gives you a smaller angle of view, as if you zoomed to a longer focal length to record the scene — or, to put it another way, as if you shot the movie using the whole sensor and then cropped away the perimeter of each frame.
The best way to understand the feature is to try it:
Set the movie size to one of the 1920 x 1080 resolution settings.
This is the only resolution that permits digital zooming. You adjust the setting via the Quick Control screen or Movie Menu 2.
Enable Digital Zoom from via the Quick Control screen, as shown in the following.Digital zoom records the movie using just the central portion of the image sensor, creating the illusion that you shot the footage with a zoom lens.
You also can turn on the feature via Movie Menu 2. Either way, select the Approx. 3-10x (zoom) option. The preview updates to show you the new framing area, as shown on the right in the above figure.
Press the Multi-controller up to zoom in; press down to zoom out.
You also can tap the zoom icon in the lower right of the screen, labeled in the figure below. The current zoom ratio appears above the little movie camera icon, as labeled in the figure.
If autofocusing, press the shutter button halfway or press the AF-ON button to set focus.
The camera automatically uses the FlexiZone-Single AF mode, using the center focus point as the focusing target.
If focusing manually, set focus by turning the lens focusing ring.
Press the Start/Stop button to start and then stop recording as usual.
To return to regular shooting, disable digital zoom via the menu or Quick Control screen.
Because you’re not making use of the full image sensor, the resulting movie quality may not appear as finely rendered as without digital zoom. Also note these other caveats:
You can’t take a still photo during recording when digital zoom is enabled.
The maximum ISO speed when using digital zoom is ISO 6400.
Autofocusing may be slower than usual because the camera has to use a different type of autofocusing than when digital zoom is turned off.
Perhaps most critically, continuous autofocusing doesn't work when digital zoom is enabled, even if the Movie Servo AF feature is turned on.