Before you start to use a new pair of binoculars, you should check them for alignment and adjust the focus for your eyes.
All quality binoculars provide independent focus adjustment of each eyepiece. The actual procedure varies from one pair or manufacturer to the next. In general the process is something like this.
The center focus knob is used to focus in on specific, distant object. It is the prime focus for the binoculars and one of the eyepieces.
The other eyepiece will have a further adjustment to compensate for focus differences between your eyes. Check the user manual for your binoculars to determine which eyepiece has the additional adjustment and where it is located. The adjustment is often right on the eyepiece, but can be located above or below the central focus knob.
To set the focus adjustment:
1. Select a distance object on which to focus
2. Focus on the object using the center focus knob.
3. Close the eye that is viewing through the eyepiece with the fine adjustment, and refocus on the object as needed.
4. Close the other eye and look through the eyepiece with the fine adjustment. Make any focus adjustments needed with the fine adjustment for that eyepiece.
That's it! Your binoculars are now calibrated. Some binoculars have a scale on the eyepiece with the fine adjustment. This can be used as a quick reference for checking the focus.
Binoculars that are not properly aligned can make focusing difficult and result in a headache after long use. You should check the binoculars for alignment before purchase, if possible, or immediately after receiving them. You can check the alignment with the following steps.
1. Adjust the binocular focus using the steps above.
2. Focus on a distant , horizontal straight line. The top of a home or building works fine.
3. Holding the binoculars as steady as possible (use a tripod if possible), position the binoculars about 8 in. in front of your eyes.
4. Alternately loo...
A good pair of binoculars is your most important tool in identifying a variety of birds. If you have never used good binoculars for this purpose, you will be amazed at the detail and color you will see. You will be exposed to a whole new world of fascinating observation.
There are several characteristics shared by all binoculars that are well suited for bird watching. Your old pair of opera glasses does not have any of them. (Well, I guess they are light weight.).
We elicited the assistance of Sharon Stitler ( aka the Bird Chick ) for information on binocular selection.
For ready reference, here are some of the items covered by Sharon.
The first number, the 7, 8, or 10, is the "power" or magnification of the binocular. Objects seen through a 7x binocular will appear 7 times closer than they really are. Objects seen through a 10x binocular will appear 10 times closer than they really are.
Beginning birders sometimes think that high powered binoculars (such as 12x or more) sound better, but most bird watchers prefer a 7x or 8x binocular. Lower powers do not provide enough magnification, and higher powers have a narrower field of view (making it harder to locate a bird using the binoculars) and can be difficult to hold steady.
The diameter of the objective lens has an effect on the "light gathering" or image brightness of the binoculars. In general, the larger the diameter, the brighter the image will be. More specifically, the diameter of the objective lens divided by the magnification provides a good indication of the potential light gathering capability of the binocular. The higher the number the better, in terms of a bright image.