Adapters Probably the most difficult aspect of digiscoping is 'connecting' the camera to spotting scope. Precise alignment of camera lens to eyepiece is critical for vignette-free, uniform illumination, and sharp focus. Many options are available and much has been discussed. Check out Andy Bright's Digiscoping Forum for user reviews and discussions of the many options that include:
You can forgo an adapter and just press the camera against the eyepiece and take a picture. This is hit and miss, and very difficult, and not considered a reliable option...
Commercial Adapters Today's spotting scope manufacturers have developed digiscoping adapters for their scopes. If you have a Swarovski, Leica, Kowa, Zeiss or Vortex spotting scope this is an option for connecting your camera to your scope. Be careful, however, since not all adapters are compatible w/ every eyepiece or camera, so talk to the scope manufacturer to make sure before buying. These adapters tend to be expensive. For your particular scope/camera combination consider contacting Eagle Optics, Andy Bright's Digiscoping Forum, or Yahoo's Digiscoping Forum for answers. I've recently begun using the new Digidapter™ digiscoping adapter for the Zeiss Vario 20-75X Zoom Eyepiece and love it!
Homemade Adapters. I'm cheap. So I make my own digiscoping adapters using plumbing supplies (PVC pipe) or household items, like pesto jar lids or plastic tubes. Check out my articles for specific adapters for specific cameras and eyepieces.
Optional accessories include cable releases, battery paks for longer camera usage, and viewfinder adapters. The latter is probably most important since the viewfinder can be difficult to impossible to see in bright sunlight. Hoodman makes an Extend-A-View makes an adapter that clips onto the back of most cameras and allow a glare-free view of the viewfinder. I've made a viewfinder using a jeweler's loop wrapped with electrical tape and velcroed to the back of the camera. It provides a magnified image of the viewfinder and shades from glare.