What is The Difference Between Low-light and Night Vision Binoculars？
When the light begins to fade, or during the early hours before dawn, activities such as nature observation, hunting, wildlife watching, and sailing into safe harbors require enhanced vision. This is where low light and night vision binoculars come into play. While they share similarities, there are distinct differences between the two types of binoculars. Let’s delve into these differences and explore what to look for in low light binoculars.
What Are Night Vision Binoculars?
Night vision binoculars build upon the technology used in low light binoculars by incorporating advanced features. They use electronic amplifiers to magnify ambient light and often emit infrared light that their optics can detect. Some models even utilize thermal imaging to identify heat signatures. These binoculars can function in total darkness but come with a higher price tag and more complex internal components. They are also heavier due to the onboard batteries needed to power the equipment.
What Are Low Light Binoculars?
Low light binoculars resemble regular binoculars but are designed to maximize the use of available natural light. They do not require a power source, relying instead on their internal components to enhance the light that enters the binoculars. These binoculars are most effective in conditions with some natural light, such as during dawn or when there is a full moon.
Key Features of Low Light Binoculars
Objective Lens
The objective lens, located at the end of the binoculars furthest from the user, is crucial for gathering light. A larger objective lens diameter allows more light to enter, illuminating the image seen through the binoculars. For low light conditions, a minimum diameter of 50 millimeters is recommended.
Field of View (FoV)
The field of view refers to the width of the image visible through the binoculars from left to right. A wide field of view is desirable as it allows you to see more. There is a direct relationship between the size of the objective lens, low magnification, and a wide field of view.
Magnification
Low light binoculars typically have lower magnification values. While it might seem counterintuitive, higher magnification can result in a blurrier image due to the natural shakiness of holding the binoculars. Magnification levels above 10x are generally not recommended for low light conditions.
Exit Pupil
The exit pupil is the diameter of the light beam that emerges from the binoculars and enters the user’s pupils. In low light, human pupils can dilate to about 7mm. Therefore, low light binoculars with an exit pupil of 7mm or greater are ideal for sufficient light transmission. The exit pupil can be calculated by dividing the objective lens diameter by the magnification. For example, a 10×50 binocular has an exit pupil of 5mm (50 ÷ 10 = 5).
Better Light Transmission
Improving light transmission is essential for low light binoculars. Key factors that enhance light transmission include:
Top Quality Glass: BAK-4 glass is preferred for binocular prisms due to its fewer imperfections.
High Quality Lens Coatings: Fully multi-coated lenses improve brightness, contrast, and light transmission.
Prism Type: Abbe Koenig prisms offer better light transmission for low light conditions, while Schmidt-Pechan prisms are suitable for daylight use.
ED Glass: Extra-low dispersion glass provides sharp images without color fringing, indicating high-quality optics.
Waterproof and Fog Proof Binoculars
Given the prevalence of moisture in many environments, investing in waterproof binoculars is wise. The industry uses an IPX code to rate waterproof items, with an IPX6 or higher rating indicating sufficient waterproofing for general use. Fog-proof binoculars have their internal air replaced with nitrogen or argon, preventing moisture-related fogging and protecting against dust and microbial contamination.
By understanding these features, you can make an informed choice when selecting low light binoculars for your outdoor activities.
