KEY FEATURES
How binoculars work
Learn how binoculars work, how to adjust focus and how to take care of them.
Two types of binoculars
- Porro prism binoculars provide better depth perception and a sharper image but are usually larger, like our Eterna Marine and Eterna Navigator marine binoculars.
- Roof prism binoculars are more compact and lightweight, like the Expert 8x32, Pocket series, Epic 10, and Scenic 8.
Beyond prism type, several factors influence image quality and user experience.
Magnification and light transmission
Binoculars are labeled with a number, such as 8x32, which means they have 8x magnification and an objective lens diameter of 32 mm. Higher magnification brings objects closer, while a larger objective lens allows more light in, resulting in a brighter image—especially important in low-light conditions.
Field of view and sharpness
The field of view indicates how wide an area you can see at a distance of 1,000 meters. A wider field of view makes it easier to track moving objects, such as birds and wildlife. Close focus measures how near you can focus on an object, which is particularly useful for butterfly and insect watching, where fine details matter. Binoculars come with either central focus, adjusted with a focus wheel, or individual focus, where each eyepiece is adjusted separately. Central focus is ideal for varying distances, such as birdwatching or general outdoor use, while individual focus is more suitable for marine use or stationary observation, where the distance remains constant.
Image quality and comfort
BaK-4 prisms provide superior image sharpness and brightness. ED glass (Extra-low Dispersion) reduces chromatic aberration (colour fringing) and enhances colour accuracy. The exit pupil determines how bright the image appears—larger exit pupils perform better in low-light conditions. Eye relief (Exit pupil distance) refers to the distance between the eyepiece and your eye, where longer eye relief ensures a more comfortable viewing experience, especially for glasses wearers.
Magnification and light transmission
Binoculars are labeled with a number, such as 8x32, which means they have 8x magnification and an objective lens diameter of 32 mm. Higher magnification brings objects closer, while a larger objective lens allows more light in, resulting in a brighter image—especially important in low-light conditions.
Field of view and sharpness
The field of view indicates how wide an area you can see at a distance of 1,000 meters. A wider field of view makes it easier to track moving objects, such as birds and wildlife. Close focus measures how near you can focus on an object, which is particularly useful for butterfly and insect watching, where fine details matter. Binoculars come with either central focus, adjusted with a focus wheel, or individual focus, where each eyepiece is adjusted separately. Central focus is ideal for varying distances, such as birdwatching or general outdoor use, while individual focus is more suitable for marine use or stationary observation, where the distance remains constant.
Image quality and comfort
BaK-4 prisms provide superior image sharpness and brightness. ED glass (Extra-low Dispersion) reduces chromatic aberration (colour fringing) and enhances colour accuracy. The exit pupil determines how bright the image appears—larger exit pupils perform better in low-light conditions. Eye relief (Exit pupil distance) refers to the distance between the eyepiece and your eye, where longer eye relief ensures a more comfortable viewing experience, especially for glasses wearers.
How to use your binoculars
Follow these steps for optimal focus and clarity:
Adjust interpupillary distance (IPD)
Fold or extend the barrels until you see a single, circular image.
Set the focus
Close your right eye and adjust the central focus for the left eye. Then, close your left eye and adjust the right eyepiece (diopter) until the image is sharp.
Binoculars with individual focus
For binoculars with individual focus, adjust each eyepiece separately—no central focus knob needed.
Adjust the rubber eyecups:
If you wear glasses, push the eyecups in; otherwise, keep them extended.
Never look directly at the sun!
Never look directly at the sun with binoculars or the naked eye—it can cause permanent eye damage!
Taking Care of Your Binoculars
Proper maintenance ensures your binoculars last for years.
- Protect the lenses: Always store the binoculars with lens covers on.
- Clean gently: Use a microfiber cloth or a soft cloth.
- Avoid moisture: Store them in a dry, cool place.
-Do not disassemble: If needed, take them to a professional for repairs or cleaning.
From compact binoculars to waterproof marine binoculars, we offer models for all types of adventures.
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