Friday, September 25, 2009

Leave your Camera Attached!

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 probably not the equipment. The blame falls squarely on the above focusing method.

Here's why.

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 due to the great variance in how 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.

© 2009 Mike McDowell


  1. I suppose the trick is that if you are going to mix then just assume that your camera sees focus differently to your eye and focus accordingly.

    this will obviously be the case if you happen to pick up a vagrant on the mudflats and need to get a verification shot.

    interesting, as always,

  2. Dale,

    Correct. And sometimes, though rarely, I'll do something like that. However, if the "action" is fast, the camera stays on. I have a greater chance of getting the shot by leaving the camera attached to my spotting scope.

    Mike M.

  3. Your identity/description of digiscopers is too narrow. I am amongst a group of biologist/researchers who use their optics primarily for field observation, searching for marked birds, noting aspects of plumage and age, etc. and leaving a camera attached would be a severe handicap, thus we practice your frowned upon behavior, but are certainly aware of the focusing issues. In this regard, using the viewfinder vs. the LCD screen might ensure better focus, since the latter is often dimmer in harsh light, as occurs in open habitats. Another caution is to beware of objects (grass & twigs) appearing in the foreground of any composed subject as cameras tend to auto focus on these when the shutter is triggered. This will not be apparent until images are downloaded for processing. The remedy is to seek a field of view offering an unobstructed view of the subject or be absolutely certain the focus field is exclusively on the subject and does not include objects mere inches in front of a subject.

  4. Oystercatcher,

    Using a view finder is not an option for the vast majority of point-and-shoot digital cameras. However, that capability would be available to afocally coupled DSLRs.

    There are a number of focusing techniques once you have your camera attached to the eyepiece.

    The purpose of this article was to point out a particular assumption with regard to focus that is often made by novice digiscopers.

    As an employee of Eagle Optics, I field calls and emails regarding digiscoping everyday, so I'm aware that this is a problem for many digiscopers. Since the overwhelming majority of digiscopers are birders, and not professional biologists, I believe my advice is catering to a far broader audience than a narrower one.

    If your particular methodology works for you, then that's what you go with. For those interested in beautiful bird portraiture, I believe my results more than compliment the techniques I advocate on my website.


    Mike M.