Part Three: Focal Length and Crop Factor
Click here to see Part Two: Auto and Manual Exposure Modes
The focal length of your lens is responsible for the camera’s “zoom.” More specifically, it represents the distance from the camera’s sensor to the point on the lens where the light converges and forms your image. Focal length indicates how much of the scene in front of you will be in your image and how small or large the objects in the scene will be. A longer focal length creates a smaller angle of view, which makes the subject of your image seem closer or more magnified. A shorter focal length creates a wider angle of view of the scene, capturing more of it and making its objects appear farther away.
The L16 has lenses with three different focal lengths: 28mm, 70mm, and 150mm. This allows the camera to take multiple images from different perspectives: the 28mm lenses take a more “zoomed out” photo, while the 70mm and 150mm lenses produce images that magnify the objects in the scene and capture a narrower view.
In digital cameras, the image sensor is what captures the light coming in through the lens and converts it to a photo. The size of the sensor dictates how much light it uses to produce the image. Full frame sensors found in today's high-end DSLRs are the equivalent size of film in older cameras—35mm film, specifically, became the prime reference point because of its popularity. When camera technology made the switch from film to digital, manufacturers introduced different-sized sensors, many of which were smaller than their full frame, 35mm film equivalents.
That introduced a problem: images appeared narrower. What was happening was the lens was projecting a full image circle, but the sensor was only recording a smaller part of it.
Focal length is supposed to indicate an image’s field of view, or essentially what is captured in it—and these smaller sensors were distorting this concept. “Crop factor” is used to counter this problem. It represents the ratio of camera’s sensor size to a 35mm film frame. Photographers use crop factor to calculate the correct focal length when their camera’s sensor is smaller than normal.
The L16 has a focal length range of 28mm to 150mm, which is equivalent to full frame or 35mm film focal lengths. Imagine a full frame DSLR with a fixed, 70mm prime lens. What you see through that lens is the same field of view as what you would see with the L16’s multiple modules at 70mm. Even though each of the L16’s sensors are small, when they are combined computationally with our lenses, they yield the same result as a full-frame camera—just in a much smaller, less cumbersome way.