Adjusting Your Binoculars
Whether out hunting, birdwatching, stargazing, or simply taking time out for a brief stroll, one should be able to rely on a pair of binoculars to produce crystal-clear views and images at a moments’ notice. One of the great things about modern binoculars is the range of adjustments that can be made with them to adapt them to weather conditions, light availability and the immediate situation. Everything from focus and magnification to interpupillary distance can be fiddled with, changed and customized to suit the users’ exact needs and specifications.
However, by fiddling without knowing what you are doing you may end up actually eliciting a sub-par performance from your binocs. Always make sure before you set out that the binoculars are set how you want them, that the neck strap is comfortable and secure, and that you know roughly what weather to expect in case you need to make raid changes to your binocular settings.
Learn to use your binoculars’ different focusing mechanisms. Most binoculars that are especially geared towards birdwatchers have two special focusing mechanisms – a central wheel used for focusing the lenses, and a diopter adjuster, designed to compensate for the differences between your right and left eyes. Unless you have perfect 20/20 vision, your eyes are going to have slight differences in the way they focus, perceive distance, and sharpen images. Make sure that both parts of the binocular are correctly focused before use, and ensure that they are correctly-spaced for your eyes. Focus on an object in the distance, and use the central wheel to bring it in to clear view. Next, close one eye, and use the diopter setting to sharpen the view. Repeat for the other eye.
The other important thing to remember when adjusting your binoculars is a little measurement known as interpupillary distance, or IPD. This term means two different things –it is both the distance between the pupils of the user’s eyes, AND the distance between the exit holes of the binoculars’ eyepiece. Most binoculars on the market fall in the 60-75mm bracket, which should be more than sufficient for the average adult. However, if set up incorrectly adjustable, hinged binoculars may not align properly with the users’ eyes, and if this alignment is not checked properly then it can result in obstruction of the target image, a big black blob appearing in the middle of the users’ vision (caused by the overlap of the users’ eyes’ visual picture) or bad, out-of-focus images.
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