Every digital point and shoot camera has Live View so what’s the big deal with having this same feature on a digital SLR? On SLRs with optical viewfinder (and not mirrorless cameras) Live View utilizes a second image sensor that’s mounted in the viewfinder’s optical path to transfer the image to the LCD. Because this second sensor is placed after a half transmissive mirror, the view via the optical viewfinder is still available. Live View is made possible by moving the mirror upwards and displaying the image on the LCD at the back of the camera as the image sensor “sees” it. Depending on how this feature is implemented both automatic and manual focusing modes can be supported. For autofocus, the mirror is flipped down momentarily and then—after the AF sensor which sits behind the mirror has taken its reading—back up again.
There are some situations where Live View provides the best way to capture an image. Live View makes it possible to check the results of exposure correction before taking the picture, permitting you to confirm any corrections, allowing you to exploit the advantages of SLR shooting in low and mixed lighting conditions. It will allow you to make adjustments more quickly while viewing the LCD , without having to check the just-captured image after every shot.
• Precise composition: Live View’s real advantage to pros, especially wedding photographers, is in its real-time monitoring of white balance. Shooting hand held outside the Café Berlin in Old San Juan, I waited until cars were coming down the narrow street before pushing the shutter release to get light trails from the headlights driving past the front of the café in the shot.
• Color correction. I made a series of photographs inside Old San Juan’s Cathedral of San Juan Bautista with the Olympus E-3 in Auto White Balance mode and got the kind of “golden” church photographs so beloved of wedding photographers in the days of film but I wanted more so I shifted the E-3 into Live View mode so I could see color balance options and how they affected the image’s color in real time. Shot with Digital Zuiko 7-14mm lens at 7mm.
• Macro photography: Some Live View cameras allow you to lock the mirror in the up position making it especially helpful for focusing on macro subjects and providing the freedom of manual focus control. Most Live View SLRs also allow you to enlarge a selected section by up to 10x to ensure focusing accuracy that is so critical in macro photography.