Whitby Gear 8x21 Compact Binocular

Magnification: 8 x 21mm refers to two key features of the monocular:

1. 8x: This means the monocular magnifies objects by 8 times. For example, an object 80 meters away will appear as if it’s only 10 meters away through the monocular.

2. 21mm: This refers to the diameter of the objective lens (the lens at the front of the monocular). A 21mm lens is relatively small, which contributes to the monocular’s compact size. While a larger lens can gather more light and offer brighter images, the 21mm size strikes a balance between portability and image quality for most casual outdoor activities like bird watching or plane spotting.

In short, this monocular offers 8x magnification through a compact 21mm lens.

Prism: Roof (K9) refers to the type of prism system used in the monocular and the material of the prism.

1. Roof Prism: This is a design used in many compact optical devices, where the prisms are aligned in a straight line, allowing for a more streamlined, compact form factor. It keeps the monocular slim and easy to carry, though it can sometimes result in a slightly narrower field of view compared to other prism types.

2. K9: This refers to the material used for the prisms, which is a type of optical glass. K9 prisms are a lower-cost option than higher-end materials like BAK4, but they still provide decent performance in terms of light transmission and image clarity. K9 prisms are commonly used in budget-friendly optics like monoculars and binoculars.

So, Roof (K9) means the monocular uses roof prisms made from K9 optical glass, offering a compact design with reasonable performance at a lower price point.

Lens Coating: FMC stands for Fully Multi-Coated, which refers to the type of coating applied to the lenses of the monocular.

1. Fully means that every lens in the monocular is coated.
2. Multi-Coated indicates that multiple layers of coatings have been applied to the lenses.

FMC coatings are designed to improve light transmission, reduce reflections, and enhance image clarity. This results in brighter, sharper images with better contrast, especially in low light conditions. The coatings also help minimize glare and improve color accuracy, making FMC-coated lenses a great feature for a high-quality optical experience.

If you're looking at an object 1,000 meters away, the monocular lets you see a 101-meter wide section of the landscape. This measurement helps you understand how wide the view is through the monocular at a given distance. A wider field of view is especially useful for spotting moving objects, like birds or planes, and gives you a broader perspective of the surroundings.

Exit Pupil: 2.6mm refers to the diameter of the beam of light that exits the monocular and reaches your eye. It's calculated by dividing the diameter of the objective lens (21mm) by the magnification (8x).

In this case:

• Exit Pupil = 21mm ÷ 8 = 2.6mm

The exit pupil is important because it determines how much light is transmitted to your eye. A larger exit pupil generally means a brighter image, especially in low-light conditions.

For example, an exit pupil of 2.6mm would work well in daylight, but in dimmer conditions, you may notice a slight reduction in brightness compared to monoculars with larger exit pupils. This measurement helps determine the quality of the viewing experience in various lighting conditions.

Eye Relief: 10mm refers to the distance between your eye and the monocular’s eyepiece where you can still see the full image clearly, without any dark edges or vignetting.

In this case, if you hold the monocular 10mm away from your eye, you will have a clear, full view through the lens. This is important for people who wear glasses, as they may need more eye relief to avoid the lens touching their glasses. A 10mm eye relief is relatively short, so it might not be the most comfortable for glasses wearers compared to monoculars with longer eye relief. However, it’s fine for people without glasses or those who can hold the monocular a little further from their eyes.

Close Focus: 5m refers to the minimum distance at which the monocular can focus on an object and still provide a clear, sharp image.

In this case, 5 meters is the closest distance the monocular can focus on an object. If you try to focus on something closer than 5 meters, the image may appear blurry or out of focus. This feature is particularly useful when you're observing things like plants, insects, or other nearby subjects while out in nature. The shorter the close focus distance, the closer you can get to your subject and still get a clear view.