VCSEL or LED IR Torch for Digital Night Vision? A UK Foxing and Ratting Guide

What an IR torch actually does. Your eyes cannot see near-infrared light, but a digital scope's sensor can. The torch floods the area with infrared, the light bounces off the ground and the animal, and some of it comes back through the scope's lens to the sensor. Two things follow. First, the light reaching the target falls quickly with distance: twice as far means roughly a quarter of the light. Second, what comes back depends on the target. Pale, dry, smooth surfaces bounce a lot back. Dark, wet or furry surfaces bounce much less. A fox in damp grass is a harder target than a white board, which is why the same torch seems to reach further on one night than another.

What a VCSEL changes. A VCSEL emits in a much narrower band of wavelengths than an LED. Makers of VCSEL modules describe them as giving more optical power with a narrower spectral width than comparable infrared LEDs, and in practice there are four consequences. First, the wavelength on the label is closer to what the torch really emits, whereas an LED rated at one wavelength spills either side of it; an 850 nm LED can show a faint red glow at the emitter for the same reason. Second, many VCSEL torches give an even, compact beam, although the beam shape comes mainly from the lens and reflector, not the emitter. Third, VCSELs are generally efficient, so more of the battery goes into infrared and less into heat. Fourth, a VCSEL is a laser emitter, which brings the safety point below.

Eye safety. You cannot see infrared, so your eyes do not squint or look away from a bright infrared source the way they do from a white torch. Treat every IR torch as something not to point at a person's face or to look into at close range, whether it uses an LED or a VCSEL. At least one major maker of LED illuminators says it uses LEDs partly because they are gentler on the eye than most laser-diode designs. Whichever you buy, read the manufacturer's safety notes, and do not assume that an invisible beam is a harmless one.

What really sets range. Five things matter, and the emitter type is only one input to the first. One, total output: makers' figures are not measured the same way, so a number on one box cannot be compared with a number on another. Two, beam angle and focus: a narrower beam puts more light on each part of the picture, but it must still cover what the scope sees. Three, wavelength against sensor: digital night vision sensors are generally most sensitive in the 850 nm region, so a 940 nm torch of the same output gives a weaker picture in exchange for being much harder for people and animals to notice. Four, the air and the ground: mist, drizzle and frost scatter infrared back towards the scope as haze. Five, the scope itself: lens aperture, sensor quality and how far you zoom, because digital zoom adds noise.

This is why we do not quote a range for any torch here. A claim of several hundred metres describes a bright, reflective target on a clear night. It does not describe a rat on a damp stable floor or a fox in long grass, and it says nothing about whether you can identify the animal and see what is behind it.

Match the beam to the field of view. A digital scope's field of view narrows as you zoom in. At low zoom it is wide, and a wide, soft beam fills it with even light. At high zoom the scope looks at a small patch, and a tight beam puts all its light there. A torch that cannot change its beam either wastes light at high zoom or leaves the edges dark at low zoom. A focusable torch lets you set the beam to the zoom you use most. A fixed beam is fine if its width matches your usual working distance. The very bright centre of a hot beam can also overexpose nearby ground, so a torch with adjustable output is better for close work.

Mounting and weight. Fit the torch on a bracket close to the scope, and line the beam up so its centre falls where the scope is looking. Check it on a post or a pale target at the distance you actually shoot, not just against a nearby wall. A big torch head, a bracket and a spare battery add weight at the front of the rifle. On a light air rifle that weight changes the balance and the way the rifle settles on a rest, so try the rifle with the torch on it before you commit. Cold weather shortens battery life, so carry a spare and use the maker's runtime figure at the output setting you will really use.

How to compare two torches fairly. Pick a dark, dry night away from lights. Use the same scope, the same settings and the same mounting position for each torch. Set out markers at distances you have measured, such as 50, 100 and 150 yards, in different materials: a white board, a piece of brown cardboard and a dark coat or bag, because a fox is closer to the cardboard than to the white board. Record a short clip from the scope at the same zoom for each torch and compare them on the same screen. Test at close range too, to see how the beam overexposes the foreground. Repeat once in damp weather. If you cannot test, buy from a dealer who will let you return the torch.

Which one for which job. For ratting around buildings with a sub-12 ft-lb air rifle, the shots are short, often 15 to 40 yards. A modest torch with a wide, soft beam is enough, and extra output is wasted. For foxing with a rimfire or centrefire rifle on open ground, beam control and output matter more, and a focusable VCSEL torch is a sensible choice. For both, never confuse the ability to see an animal with permission to shoot it. Identify the target, check the backstop, and shoot only within your rifle's proper range.

Law. Shooting at night needs the landowner's permission and has to comply with the law for the firearm and the quarry. Our UK night vision and thermal law guide covers the ground. This is not legal advice.