I’m sure you’ve seen the following digiscoping practice in the field. Using a spotting scope, a birder scans terrain and habitat when something of interest grabs his attention. Perhaps it’s a shy Sora that has sauntered into the open from thick marsh grasses, or maybe a beautiful Magnolia Warbler has perched on a bare branch. Now the birder turns digiscoper, swings his scope around, focuses the eyepiece on the bird, removes his digital camera from a pouch or coat pocket, brings its lens up against the eyepiece, and proceeds to take photographs without refocusing the spotting scope’s eyepiece.
One of the most common complaints from digiscopers, novice and experienced alike, is that their images often appear out of focus. Well, it’s not the equipment. The blame falls squarely on the above focusing method.
Consider the fact that when you’re sharing your spotting scope with another birder, they’ll often need to refocus the image after you’ve finished looking through it. This is because there are lots of different ways our eyes are uniquely imperfect:
Unless you happen to have exactly the same vision as the other birder, you’ll generally disagree what the spotting scope’s perfect focus is. Even subtle structural differences in your eyeball will account for the disagreement in focus. The problem with the above focusing method becomes clearer when you consider that the digital camera acts like another person’s eyeball. There’s no guarantee that what the camera “sees” as a perfectly focused image is the same for you, or another birder. Hence, if when digiscoping you focus through the eyepiece of a spotting scope and then hold the camera to the eyepiece without refocusing, there’s a pretty good chance the image will be out of focus, even when an auto-focus is applied.
The majority of world-class digiscopers I know tend to leave their digital camera attached to their spotting scope for the duration of their digiscoping session. I’m no exception. However, when I first began digiscoping over 8 years ago, I fiddled around with several different focusing techniques before settling on just one. Today I have a tendency to divide my outdoor excursions into two categories: Birding or Digiscoping and seldom mix the two activities. When I choose to go birding, I generally won’t carry my spotting scope along. On those particular days I desire to enjoy birds as an observer and documenter. However, on digiscoping days I configure my spotting scope for digital photography before I go out in the field. The camera’s turned on. I’m ready. I use my binoculars to scan for potential subjects, and then carry my rig to the spot. In preparing to take a photograph of a bird, I locate, view, and focus the image via the camera’s LCD monitor. Whatever your personal vision is, what’s in focus for you on the monitor should be in focus for everybody else.