The ISO Auto mode on digital cameras gives you additional flexibility by letting the camera adjust the ISO speed to achieve the correct exposure—so different from film cameras where the ISO speed is fixed! But it could cause your shutter speed to slow, increasing the chances of camera shake and subject blur especially when shooting moving subjects handheld. Don’t fret: there’s a “hidden” setting found on enthusiast and advanced Canon cameras that will help prevent unwanted blurring. Read on to find out more! (Reported by: Fuka Kamata, Digital Camera Magazine/ Models: Hitomi Yamaguchi, Kino Yamaguchi)

EOS R6/ RF24-70mm f/2.8L IS USM/ FL: 46mm/ Aperture-priority AE (f/5, 1/1000 sec, EV +0.7)/ ISO 320/ WB: 4,800K

 

ISO Auto with Av/P mode: What happens if shutter speed becomes too slow?

A bit of movement can give a portrait extra life. For the image above, I got the mother and daughter to walk and run around so that the shot would look more dynamic.

But when I shot in Aperture-priority AE mode without doing anything to the ISO Auto menu settings, the shutter speed became 1/100th of a second. This was not only slower than I wanted but also resulted in subject blur.

Av mode, ISO Auto, no minimum shutter speed: 1/100 sec

Close up of the area in red. At 1/100 seconds, there is subject blur.

 

The solution: ‘Minimum shutter speed during ISO Auto’

Easier than switching to Manual mode!

The slowdown in shutter speed occurs in the exposure modes where the shutter speed is automatically set by the camera, such as Aperture-priority AE mode, Program AE mode, or Flexible-priority AE mode with both ISO speed and shutter speed set to "Auto". But you don't have to forgo the convenience of these modes if you have an enthusiast or advanced EOS camera such as the EOS M6 Mark II, EOS 90D and above, or the EOS R system. These models offer an easy solution: the manual 'Minimum shutter speed during ISO Auto setting*.

How to set the ‘Minimum shutter speed during ISO Auto’

1. Press the MENU button.

2. On the SHOOT menu, look for and select the following item:

3. Select ‘Min. shutter spd.’

4. Select “Manual” and choose the minimum shutter speed you require for your subject*.

Once you have set this, as long as you are in Av or P mode and using ISO Auto, the camera will set an ISO speed that prevents the shutter speed from becoming slower than the value you selected.

*Available shutter speeds depend on the camera.

With this minimum shutter speed setting, you can rest assured that the shutter speed will never go slower than what you intended. No more failed shots due to camera shake and subject blur! 

 

Bonus tip: Make sure you are using Servo AF

The first step to getting any subject sharp is to make sure that it is in focus. When photographing moving subjects such as children, make sure that you are in Servo AF mode (or AI Servo AF mode if you are shooting with the optical viewfinder (OVF) on a DSLR). In this mode, you just need to establish focus once, and the camera will keep tracking the subject even when it moves around.

Tip:
- During Live View/ EVF shooting, when Servo AF is active, the AF frame is blue. If the frame is green, you are in One Shot AF mode.
- Set the AF mode to ‘Face Detection + Subject Tracking Priority’ mode to keep focus on the face. If your camera supports Eye Detection AF during Servo AF, make sure that it's enabled!

For more cool ideas and useful techniques for portrait photography, check out:
Portrait Relighting: Your In-Camera Lighting Crew
2 Instant Techniques to Liven Up Your Outdoor Portraits
3 Ways To Capture Adorable Sibling Photos
Shoot Beautiful Night Portraits with No Tripod, No Flash
[Flash Technique] Creating a Pop Art-inspired Night Portrait
 

 

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