Taking good digiscoping images requires high-quality equipment and a high level of familiarity with its use.
Preventing vignetting
Use the zoom lens on the camera to zoom in and see if you can eliminate the black areas around the edge. Remain within the optical zoom range and do not use the camera’s digital zoom! Using the digital zoom will result in a loss of image quality.
Avoiding blurring
There are a number of reasons why digiscoping images may be out of focus. You should bear the following in mind when digiscoping:
1. Ensure that the telescope is focused properly
The camera can only capture the image that passes through the telescope. The better the telescope is focused on the subject, the better the result.
2. Select the right camera settings
When digiscoping, the aperture size, exposure time (or shutter speed) and ISO sensitivity have a large influence on image sharpness. The high level of magnification created through the combination of telescope and camera results in a high risk of blurring. The aperture is the opening through which light passes in order to reach the camera’s sensor (CCD).
The size of the aperture (referred to as an f-number, e.g. f2.4 or f5.6), determines the size of the aperture opening and, therefore, the amount of light that is admitted into the camera. To ensure that images are exposed correctly, higher f-numbers (e.g. f7) and the correspondingly small aperture openings require longer exposure times. If the f-number is higher, the aperture opening is larger which can reduce the exposure time.
The following applies in principle: the shorter the exposure time, the lower the risk of camera shake that would result in blurring.
We therefore recommend that you use your camera’s automatic ’Speed‘, ’Sport‘ or ’S‘ exposure mode (if available). This means that your camera will select the shortest possible exposure when the shutter release is triggered.
The camera will select the most suitable ISO sensitivity for the prevailing lighting conditions automatically, although you can also change this manually.
Low ISO numbers, such as ISO 100 and 200, are intended for use in good lighting conditions. If the environment is darker or has poor lighting, you should select a higher ISO number such as ISO 400 or 800.
In other words, you are unlikely to go wrong if you select the most suitable level of ISO sensitivity (the automatically selected sensitivity is usually correct) and use the ‘Speed‘ programme setting. At most, you may need to change the ISO number if the light becomes weaker or you want to photograph fast-moving subjects.
3. Use your camera’s self-timer or remote control
Rule number one: avoid all unnecessary movement! Even the pressure of your finger on the shutter release button can often be enough to cause camera shake. The camera’s self-timer is ideal for overcoming this problem. You have two options: use either the camera’s in-built self-timer or a remote control (not available for all cameras). The camera itself provides the first option; the second enables you to trigger the shutter release without needing to touch the camera. However, there are a decreasing number of camera models on the market which feature an electronic (remote control) or mechanical (cable) remote shutter release.
4. Ensure your equipment is stable (tripod)
Ensure that the telescope and camera are highly stable when taking the image and that they are not subject to any movement. A tripod is essential for sharp, high-contrast images when taking photographs, much more so than when observing. Optimal stability makes a considerable contribution to image quality.
Keep the tripod legs and centre column as low as possible when shooting to allow them to dampen vibrations more efficiently.
It is particularly important that the telescope, eyepiece, adapter and camera are all perfectly balanced on the tripod. The telescope rail for Swarovski Optik telescopes allows this to be done quickly and easily according to your specific requirements. If the tripod head is not fixed, aim to position the entire setup on the telescope rail in a way that ensures a horizontal balance. This will prevent the setup from shaking or moving when you move from your observation position to take photographs.
5. High-quality optics
High-quality optical and mechanical materials, the lowest tolerance limits, 100% quality control – just some of the parameters for outstanding optical performance. Be sure to seek out the best quality when choosing your camera, telescope and eyepiece. High definition (HD) lenses in particular help ensure that the images reproduced are bright with lifelike colours.