I don't know whether the 303 you mentioned is the same model as NQ-502. If yes, you can refer to the following focusing methods:

Twelve: Focus, find the focus.

Nuoqing laser focusing flashlight can achieve the best thermal effect by adjusting the laser focus.

The laser adjusted by the lens of the flashlight head will form a focus at a certain position of the flashlight head.

Generally, the focusing range of laser is within 1 meter outside the light exit.

The best focus position is adjusted to the distance from the light outlet 10-20 cm, that is, the thermal effect is the strongest at the focus formed by the laser in this range.

How to find the focus of the laser through adjustment is very important for players who like to have something to play with.

Let's talk about one briefly.

When you start to touch the laser flashlight, you can hold down the laser switch with one hand, irradiate the laser in a slightly dark place, and then adjust the focus ring with the other hand, slowly and finely. While adjusting, observe the light within 20 cm from the torch mouth, and you will find that the light will change slightly with the adjustment, and it is the smallest at a certain point, so this point is the focus of this position.

With the constant adjustment, you will find that the thinnest point is moving slowly, which means that with the adjustment, the focus of the laser is moving.

Generally, the thermal efficiency of the focal point is the largest in the range from flashlight 10-40 cm.

If the light is not obvious, friends who smoke can spit a cigarette on the laser lamp, and they will obviously see that the light at a certain point is the thinnest, that is, the laser focus at this distance.

You can also let the laser hit an object, such as a keyboard or a match. The optimum distance is about 10-20cm.

Then, while adjusting the focusing ring, observe the size of the laser spot that hits the object. With the adjustment, the laser spot will change from large to small, or from small to large.

When it is observed that the laser spot hitting the object is the smallest, it is the focus of the laser at this distance.

It should be noted that the focal length should not be adjusted too close to the flashlight, for example, within 5 cm. In this case, if you point at an object at close range, the smoke emitted by the object may dirty the lens. Generally, it is best to set the focus position in the range of 10 cm -20 cm, where objects and smoke will not affect the lens.