Today’s Post by Joe Farace
Most digital point and shoot cameras have optical zoom lenses that allow you to vary their focal length and change the size of an image being captured on the imaging chip.
In most camera advertising, zoom lenses are often described by the ratio of their longest to shortest focal lengths. A zoom lens with focal lengths ranging from 100-400 mm can be described as a 4:1 or alternatively 4X zoom, a specification I dislike because it ignores the starting and ending focal lengths that I think are much more important that just the ratio.
For an example of an extreme optical zoom camera, you can read my review of the Nikon Coolpix P1000 that has a 125x zoom ratio here.
Many cameras these day, even sophisticated mirrorless cameras, also offer a digital zoom feature that is produced by cropping the captured image in-camera and then interpolating (making it larger) to emulate the camera’s maximum resolution. This process always produces a lower quality photograph than that what would normally be captured with an optical zoom lens because you are tossing away parts of the original’s image resolution.
Question: Was this classic car at top cropped or was it photographed using a digital zoom and does it even matter?
Answer: It was cropped from the original photograph—after the fact.
You can achieve the same effect as a digital zoom by cropping the original file with even the least expensive image-editing program.
So what’s the big deal about digital zoom? It’s all about marketing not photography, so don’t be fooled when the manufacturer erroneously combines the ratios of both optical and digital zooms giving you double the amount of worthless information.
For more about cropping read my post “How I Crop My Drag Racing Photographs.”