What does the circle on the camera lens mean? What do gold, red and blue mean? Beginners please give me more advice.

The red circle is the professional L lens, the gold circle represents the USM ultrasonic motor, and the blue circle represents the technical verification lens.

In Canon's lens system, all Canon's L lenses represent the highest optical quality. L The lens has a red circle in front of the lens barrel. On the model, the red circle head also has an L, such as EF-S 18-200mm F3.5-5.6 and EF 24-70mm2.8L USM, which is the red circle head. Therefore, Canon's red circle head is easy to identify.

Extended data

According to the performance and shape of the lens, there are P-type, E-type, L-type and auto-zoom lenses. ? Automatic positioning lens, its pupil focal length has been adjusted, and it is necessary to check whether the definition from maximum magnification to minimum magnification is consistent and clear.

L-shaped lenses are common industrial lenses, and the pupil focal length needs to be adjusted manually. After the machine is installed, manually adjust the maximum magnification and minimum magnification, and the image is also clear. Those whose sharpness cannot be adjusted are regarded as defective products, and those with unstable factors such as jitter after adjustment are also regarded as defective products.

Baidu encyclopedia-red circle lens