What Is a Digital Teleconverter?

A digital teleconverter is a type of lens that attaches between a single lens reflex (SLR) camera and an additional photographic lens. This lens enhances zoom capability by focusing in on the central part of an image and enlarging it. Not only does this draw distant objects closer into a photographic frame, but it also enhances the image's resolution and quality. Typically designed for snap-in attachment to a camera face, this lens processes an image obtained by an objective lens — whatever main lens is being used. By adopting this smaller component, photographers can increase their shooting range without expensive telephoto lenses.

There are two types of camera zoom: optical and digital. Optical zoom relies on mechanically shifting lenses to affect detail or depth of field. Digital zoom manipulates images at the pixel level by enlarging them and cropping the edges. This can result in detail loss and stairstep effects. Using a digital teleconverter offers an intermediate stage between simple digital enlargements and high-cost precision optics.

The circle of illumination refers to the light captured by the objective lens in the main area of focus. A digital teleconverter enlarges that image portion and delivers it to the camera. An individual lens performs according to its specifications. Typical ranges are 1.4x and 2x. In addition, 1.7x and 3x are also commonly available.

Essentially, these numbers refer to how many times a camera's focal length is increased. A digital teleconverter greatly enhances the camera's ability to catch more vivid detail far away. This can mean the difference between shooting the color of the grass stains on a football player's uniform on the far end of the field, or the color of the grass in his teeth.

Once achieved with a costly telephoto or zoom lens, this technology multiplies the zoom effect in balance with other camera and lens setting factors. That's why a digital teleconverter is sometimes called a multiplier. This capability, however, also carries certain costs.

Channeling an image through this component decreases resolution and light intensity. In addition to camera heft, image shake and focusing speed begin to weigh in. This component might also magnify an image aberration or interfere with a camera's autofocus. For the cost savings, experimentation to balance out these factors might be well worth an avid photographer's time.

Having a digital teleconverter in the camera case empowers a photographer with much more versatility when it comes to capturing images. Not all digital teleconverter products, however, are compatible with all brands of camera or other lenses. By using the right device, a shutterbug may find that catching vivid detail in elusive objects, like the lens itself, becomes a snap.