The Portland Metro Photographic News

(Or What's This Little Dial Next To My Viewfinder?)

by Tom Hubbard

Probably not. But your camera may need adjusting to "see" as you "see".

Unfortunately, not everyone has 20/20 vision. Everyone's eyes have their own unique focusing characteristics. If your DSLR isn't adjusted to the focusing capability of your eyes, less than sharp images will likely result. For regular eyeglass wearers or those requiring reading glasses, you already know that there is probably a difference between your eyes and standard factory viewfinder settings. This eye-versus-camera vision discrepancy even comes into play when you rely on autofocus mode.

There is a simple solution built in to most DSLRs -- a solution and adjustment that should be checked frequently.

Diopter adjustment control on a Nikon D200

A small, and often under used control dial, located next to your camera's viewfinder adjusts the diopter settings of the camera. This simple control plays a critical role in adjusting the camera's viewfinder to your eye's characteristics. Making the diopter adjustment is easy and quick:

• 1. Find a large piece of plain cardboard. Any light color will do. (OR find a well-lit blank wall.)
• 2. Turn OFF your camera's auto focus. Use manual focus. Set the lens focusing ring to infinity. We want the lens to be WAY out of focus.
• 3. Point your camera's lens at the cardboard or blank wall. Get close enough to the cardboard or wall to completely fill your viewfinder. Don't focus on the cardboard. Leave the focus set at infinity.
• 4. Look through the viewfinder and (in the case of this Nikon camera) you will see eleven small boxes in the viewfinder. Other cameras may use a different focus target scheme, but you will see similar targets when you look through the viewfinder of your camera:

Shown above are the boxes seen in a Nikon D200 before starting diopter adjustment.

Notice that the boxes are soft or out of focus.

• 5. Concentrate on the boxes. Turn the camera's diopter adjustment in either direction until the boxes become very sharp (in focus). If the boxes become even more out of focus, turn the knob in the opposite direction. Eventually you will find a knob position where the boxes are sharp.

Turning the diopter adjustment brings the target boxes into focus.

• 6. That's it!  Your camera's viewfinder is now customized to your eye.

Once the boxes are sharp, your viewfinder is adjusted to your specific vision. Check this adjustment frequently because it is possible for the diopter control knob to be accidentally moved during normal camera handling. Since the process only takes seconds and can be done anywhere, it's well worth the time invested.

This adjustment has NO impact on the automatic focusing feature of your camera which will continue to work as before.The danger in not adjusting the viewfinder to your vision is that you may think the auto focus mechanism has incorrectly focused your camera causing you to incorrectly override the suggested focus setting. Or the camera may have selected the wrong object as its focus point, and you may not be able to "see" this inaccuracy and make the necessary correction.

Even if you have perfect vision,there is always the chance that the diopter control knob has moved during normal camera use (e.g., while taking the camera in and out of the camera bag, while changing other camera dial settings, etc.) It's best to synchronize all these visual picture taking components -- your eye, the camera's viewfinder and the autofocus system. And that's the function of the diopter adjustment control knob.

Occassionally, photographers want to check their diopter setting in the field. Since most photographers don't normally carry a large cardboard or blank wall into the field, they will substitute a blank area of the (blue or overcast) sky. The procedure is exactly the same.

It's not rocket science, but this simple viewfinder calibration procedure will help to get your photography off the ground.