TELEPHOTOGRAPHY
with compact digital cameras and camcorders
CLICK HERE for information on telephotography with SLR & D-SLR cameras
Overview
The nature of image capture with digital compact cameras and camcorders means Opticron telescopes can be used as high magnification telephoto lenses for wildlife photography and filming. There are however limitations to these applications namely due to the high magnifications involved and the fact that telescope eyepieces are not designed (mechanically or optically) to transmit light into the camera/camcorder lenses.
The vast majority of compact prismatic telescopes are designed for use with viewing eyepieces ranging in magnification from 20x to 60x. Using a telescope fitted with a 20x eyepiece in combination with a camera/camcorder with an optical zoom of between 0.6x and 20x, it is possible to take some very high magnification images of wildlife, but the small effective apertures, fields of view and depth of focus put a limit on the quality of the final image and one’s ability to successfully frame a shot.
In addition it is often difficult for the viewing eyepiece to project a large enough dia. path of light into the camera lens and onto the CCD within. This results in a partial image being created in the camera and a condition known as vignetting or circular image within the available rectangular image frame. Vignetting can be 'cropped out' of the final image using photo editing software but the final image will be equivalent to using a very narrow field eyepiece.
To get the best results;
Choose a low magnification wide angle eyepiece for your telescope when using it for telephotography. As a general rule, the following eyepieces provide the best overall images with a wide range of different compact digital cameras. To help they have been graded according to particular requirement.
- Overall image quality: 40810 HDF T or HR 40812
- Flexibility across the widest range of different magnifications: 40935 SDL zoom or 40862 HDF T zoom
- Taking pictures at lower magnifications: 40937 HDF T or 40929 DTL
Choose a camera/camcorder with a small lens diameter. The smaller the lens diameter the more of its' surface area will be covered by light exiting from the telescope eyepiece. Commonly camera lenses of diameter less than 20mm give best results and camera lenses over 30mm in diameter will require at least 3x optical zoom to attain a 'full frame' image.
Use the optical zoom on the camera/camcorder to effectively reduce the aperture of the lens to 'match up' with light exiting from the eyepiece. Remember the higher the optical zoom setting, the higher the magnification of the final image. E.g. 20x eyepiece plus 3x optical zoom = 60x (assuming the default magnification on the camera = 1x.)
Important note. In addition to eyepiece magnification and camera lens diameter, variables such as eyepiece eyerelief and field of view plus individual camera zoom-lens mechanisms all play an important role in achieving the best overall 'set-up' for this type of telephotography. There is therefore no substitute for individual testing.
