Thermal binoculars are optical devices which are used to amplify the available visible light and also to view the infrared light from the object. The visible light (7 colors which we see) is a small part of the electromagnetic spectrum. Human eyes are very much responsive to this visible light.
Without this visible light our eye can’t see any object in the dark. Apart from the visible spectrum there are also various other waves like radio waves, microwaves, alpha rays, gamma rays etc. An object always emits some of these waves at different rates.
As our eye captures the visible light from the object, thermal binoculars are devices which capture the IR rays from the objects. By using these IR rays visualizing the entire image of the scene is very much possible even in acute darkness. But, the entire scene shall seem to be a monochromatic image with a green hue.
Even though, these optical devices are primarily used in military and law enforcement they are also gradually conquering every field of science proving to be indispensable. Listed below are some of the factors which you need to consider before getting a thermal binocular.
A lens is an optical device which converges or diverge the light. The power of the lens is usually measured in dioptre. A good lens should provide a good vision of the scene in front of the device. The magnification of the lens is usually mentioned in terms of 2 numbers with a multiplication symbol between them. Say 7×35 for example.
Here the first number is the result obtained by dividing the focal length of the objective lens by the focal length of the eyepiece. In other words, it says that the binocular can produce 7 times larger image than the real one. The second number (i.e. 35) is the diameter of the objective lens. Larger the magnification, larger is the quality of the image.
A battery is an electrochemical device which supplies power to the entire system. The thermal binocular should not be very much power hungry. If it consumes more power, then frequent charging need to be done which can be annoying at times of emergency.
A binocular with the least usage of power can be of great use, especially when you go for a long hike. Moreover, the number of batteries required by the device should be as low as possible thereby minimizing the weight for the user. Checking for the updates for the usage of rechargeable batteries shall also help your cause.
3. All Weather
Thermal binoculars have been used by hunters, military, surveillance, firefighters, etc. All these situations are not confined to a particular weather. These unfortunate incidents may happen at times of heavy, rain or snow. So, the system should not prove to be a failure, even when it encounters different climatic conditions.
Moreover, it should be able work efficiently even when the sun is at its peak and when the device is dipped inside the water. For that, the binocular needs to be a waterproof device which can operate better at chaotic circumstances.
For any newly manufactured device, the foremost feature which needs to be sufficed is its portability. No individual in this world shall buy this expensive thermal gadget to sit at their couch and view their garden. It is mostly purchased for outdoor uses.
While packing for outdoors, the thermal binocular should not occupy more space inside the bag. Furthermore, binoculars which can be folded into a compact size are mostly preferred by the outdoor enthusiasts.
The next factor after portability is the weight of the device. We know that a thermal binocular is a device which is used to see the distant in a dark environment. If you have left your binocular hanging on your neck, its weight can cause sprains and burns around your neck.
Furthermore, it is installed on your hat, then it can pull your neck in front and so you have to keep your neck tight to keep your head straight which is really painful. Hence, the weight of the device should be carefully analyzed before you get one.
Photosensitivity is the minimum amount of light required by the device to operate effectively. At the light below, the photosensitivity of the device the binocular cannot produce the required image. The devices of various generations have different photosensitivity thereby making the 2nd generation binocular to operate well in minimum light comparing to the 1st generation device.
7. Image Quality
The quality of the image depends upon its resolution. The first generation thermal binoculars have a resolution below 1000, whereas the second, third generations have a resolution around 20000, 50000. Stabilization of the images should be high as the resolutions increases.
The effect of the shaking movements should be reduced even if it is not supported by a tripod stand thus enhancing the quality. Even though, the monochromatic green screen shows a clear image, clarity of the fine details of the image shall prove the quality of the image.
Thermal binoculars come in various sizes, colors, resolutions etc but holding it always in your hands is totally absurd. You need to perform various other duties also while going out for an expedition.
So, it is crucial to fetch a binocular which can be easily surmounted and dismantled from your hat. This way, you don’t have to repeatedly check your surroundings by holding the device in your hand.
Spectrum is the technical term which involves all the electromagnetic radiations with distinct features of wavelength, frequency, amplitude etc. Apart from the visible spectrum which lies from 400 to 750 nm, there are various other regions like ultraviolet region which expands from 100 to 400 nm, infrared region from 750 to 2500nm.
Since the infrared region occupies more regions, it is further divided into three divisions which include, near infrared, mid-infrared, thermal infrared regions. A worthwhile thermal binocular should be able to operate in all these regions proving it to be a sophisticated device.
10. Bright Light Exposure
Although thermal binocular are breathtaking optoelectronic devices, prolonged exposure of this device to the extreme bright light can cause damage as it is designed for the nocturnal activities.
There are reinforced thermal binoculars which close their shutters when they are exposed to extreme light. Moreover, automatic switch off mechanisms are also available in some branded devices to save it from bright light.