How to Synchronize Image Sensors

Flash sync freezes a moment in the appropriate light.

A picture has always been a world unto a single moment. In still photography, a camera's shutter opens and closes at a speed that exposes your shot to an image sensor. The shutter speed is the amount of time that the shutter must stay open for sufficient light to imprint the image sensor. Flash synchronization is the moment when a camera's flash goes off while the camera's shutter is open. The more natural light, the less flash is needed. In the digital age, synchronization makes easy work of a photographer's determination to deploy a camera's flash for optimum effect.

Things You'll Need

• Camera operator's manual

Instructions

1. Check "Specifications" in your operator's manual to determine the size of your camera's image sensor. Different sensor sizes influence shutter speeds. Check "Sensor Sizes" in References for more.

2. Locate the "Flash" indicator icon in your owner's manual. In cameras with LCD menus, this indicates that the camera's sensor is detecting enough light. Many cameras use a lightning bolt to indicate "flash."

3. If using a digital camera in automatic mode, frame a picture and press the picture button halfway while looking through the viewfinder. If the flash is needed, the icon will appear in the viewfinder. This means that the camera will use its flash when you take the picture.

4. If you're in manual mode, turn "on" the camera's flash (if necessary) by selecting its icon for display in your viewfinder.

5. Take the picture.

6. Confirm flash sync effectiveness by viewing the picture (if possible) on your camera's display screen.

7. Adjust flash sync according to one principle: the more you need a flash, the slower the shutter speed that is required.

Tips & Warnings

• Carefully consult your owner's manual for information on back-lit pictures, or bright lights in a dim setting. These can make flash sync a little more challenging.

• Familiarize yourself as soon as you acquire the camera. Flash sync is an acquired knowledge, so practice with various kinds of light exposures before taking "all-or-nothing" shots, such as a wedding.

• Don't be surprised if your camera automatically lowers a shutter speed when you select "flash synchronization" in manual mode. That is the fastest speed available, and many situations do not call for it.

• Don't freak out if your flash goes off once before the shutter opens, then again when you take the picture. This is the camera's way of bathing the shot in flash light.

References

• ShortCourses.com: Flash Sync and Shutter Speeds; Dennis P. Curtin.
• ShortCourses.com: Flash Sync (Animation); Dennis P. Curtin..
• Awaiba.com: Glossary (Sync/Image Sensors).
• Photography.com: Flash Sync Speed.
• Digital Photography Review.com: Sensor Sizes; Vincent Bockaert.
• Digital image sensors; Norman Koren.

Resources

• Photographic Society of America (PSA): Home Page.
• Namemedia.inc.: Digital Cameras - A Beginner's Guide; Bob Atkins.