Depth of field

Depth of field of CCTV lens means that after the camera lens is focused, a clear image can be formed in the range before and after the focus. This range of distance is called depth of field.
Aperture, lens, and subject distance are important factors affecting depth of field:
1. The larger the aperture, the smaller the depth of field, and the smaller the aperture, the greater the depth of field.
2. The longer the focal length of the lens, the smaller the depth of field, and vice versa.
3. The closer the subject, the smaller the depth of field, and the farther away the subject, the greater the depth of field.
4. The depth of field is greater than the depth of field.

Miniature object distance

The closest object distance of CCTV lens is the distance from the center of the lens at the forefront of the lens to the closest object that can be clearly imaged.

CS and C mounts

The rear flange distance of the CS interface lens is 12.5mm, and the rear flange distance of the C interface is 17.5mm. CS-mount CCTV lenses can only match CS-mount cameras, but C-mount lenses can match C-mount lenses by adding a 5mm C-to-CS adapter to match CS-mount cameras.
Back flange distance, back focus, mechanical back focus
The rear flange distance is the distance from the lens interface to the camera sensor.
Back focus is the distance from the center point of the last lens of the lens to the camera sensor.
The mechanical back focus is the distance from the front end of the lens interface to the camera sensor.

Comparison of non-IR lens and IR lens

Day and night cameras are generally used at night near infrared or infrared environment. If you use a lens without IR correction function to match the day and night camera, the camera will not be able to focus clearly when used at night. EVETAR lens uses glass lens supplemented by special optical design and multi-layer coating to reduce light refraction to achieve day and night confocal. This eliminates the need to refocus the camera when it is used at night.

Megapixel

CCD and CMOS image sensors use pixels arranged in a two-dimensional grid. These pixels convert optical images into electrical signals. The number of pixels in an image usually determines the resolution of the image. More pixels means higher resolution. A megapixel is one million pixels. Megapixel cameras are cameras that use megapixel sensors.
Match megapixel lens for megapixel camera

In order to get the best performance from a megapixel camera, it will be very important to use a high-quality megapixel lens, so the quality of the optical image is a key factor in the overall image quality of the film. Megapixel lenses provide high contrast, sharpness and sharpness for the entire image. A non-megapixel lens cannot fully represent the high resolution of a megapixel sensor, especially at the edges of a picture.

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