Digiscoping
From Wikipedia, the free encyclopedia
Digiscoping is a method of obtaining photos using a digital camera through a telescope or, less often, binoculars. Afocal projection is a method of astrophotography in which photographs are taken by holding or mounting the camera over the telescope eyepiece, with the camera taking the place of your eye. Afocal projection is the method most commonly associated with digiscoping.
Contents |
[edit] Benefits
- Cost-effectiveness — Reasonable to good results can be achieved using digital cameras (and even old webcams), attached to a telescope removes the need for a large expensive telephoto lens. Not having to use telephoto lens also allow the users to upgrade the camera, buying another brand because the telescope is compatible with wider range of models/brands of camera compared to telephoto lens.
- Compact — For birders and nature watchers that are already carrying a scope, the additional size and weight of a few adapters and a small compact digital camera is fairly insignificant.
- Extremely high effective magnifications — High effective magnification, often more than any commonly available telephoto lenses. Focal lengths equivalent to 2000mm and more on a 35mm film camera are common.
- No camera vibration — The compact cameras typically used do not suffer from the image degrading vibration and noise caused by the moving reflex mirrors of SLR type cameras.
- Preview and recapture — digital cameras provide a preview on the LCD viewer while aiming, or after capturing. User can delete and re-take the picture if she is not satisfied with the earlier attempt.
- Digital image format — images are already in digital format, and thus can be easily modified and enhanced as necessary using digital image editing software.
- Autofocus — Camera based contrast detect autofocus is often still functional to assist in fine-tuning final image focus.
For the best possible results, it is crucial that the optical axis of both the camera and the telescope are aligned. The distance between the camera objective and the telescope eyepiece is also important and typically is adjusted by trial and error. Originally, attaching the camera to the telescope would greatly depend upon the craftsmanship of the photographer, though there are now many commercial adapters available. The quality of the telescope and eyepiece are critical factors. Scopes that use objectives with special refractive elements and scopes that use a reflex or catadioptric design yield the best results because they control chromatic aberrations well.
[edit] Astronomy
Digiscoping is a modern form of the telescope photography long practiced by astronomers. Telescope photography is a technique of combining a camera with a telescope to capture images, a standard practice among astronomers. Historically the 35mm SLR or large format film cameras would be used for this purpose. The advent of the digital camera has introduced a new set of issues, with many advantages but a few key disadvantages.
Astronomers tend to take long-exposure photographs of celestial objects and because of this astronomers originally found digital cameras somewhat problematic due to their high inherent sensor noise. This noise limits their usefulness for long-exposures, especially since point-objects, such as stars, can be obscured by even one "hot" pixel. Continuing advancements in digital camera and image manipulation has somewhat overcome this limitation and digiscoping astronomy has become more popular. In daylight situations where long-exposure times are not required, such as birdwatching, the sensor noise issue is not a problem.
Other than the above, for digiscoping astronomy, a proper telescope mounting and tracking mechanism is also essential due to the movement of stars, and long exposure required to capture distant, low light stars.
[edit] Bird Watching
This technique is also practiced by birdwatchers. Birdwatchers found the digital camera to be a particularly effective addition to their field telescopes and quickly adopted the digiscoping technique. This technique is called digiscope birding. For this variety of digiscoping, fast shutter speed and minimal shutter delay are more essential due to bird movement.
When not birding, some birdwatchers enjoy using their digiscoping equipment to photograph plants (for example, wild orchids growing in the canopy of a jungle), insects (for example, wild bees near their beehive), other shy or dangerous wild animals, or details in old buildings (for example, statues/gargoyles on the roof of old churches/castles).
[edit] Other Variants
A recent variant of digiscoping using a camera phone in place of a digital camera is known as phonescoping. The advantage of phonescoping is that one can, for example, send an MMS directly to another birdwatcher to aid or confirm identification.
