Important parameters of surveillance cameras

It is an index that measures the amount of light transmitted through the lens. The aperture value is represented by the F value. The smaller the F value, the greater the amount of light passing through, and the brighter the image formed by the lens. The F-number is inversely proportional to the lens aperture and directly proportional to the focal length.

The ratio formula is as follows:

F value = f / D (f: focal length, D = lens aperture) Depth of field refers to the range before and after the focus after the camera lens is focused. A clear image can be formed. This range of distances is called depth of field.

Aperture, lens, and distance from subject are important factors that affect depth of field:

1. The larger the aperture, the smaller the depth of field, and the smaller the aperture, the larger 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 is, the smaller the depth of field, and the farther the subject is, the greater the depth of field.

4. The near depth of field is greater than the far depth of field. The rear flange distance of the CS mount lens is 12.5mm, and the rear flange distance of the C mount lens is 17.5mm. CS mount lenses can only be matched with CS mount cameras, but C mount lenses can not only match C mount lenses, but can also be matched with CS mount cameras by adding a 5mm C to CS adapter ring.

Rear flange distance, back focus, mechanical back focus

The back flange distance refers to the distance from the lens interface to the camera sensor.

Back focal length refers to the distance from the center point of the last lens of the lens to the camera sensor.

Mechanical back focus refers to the distance from the front end of the lens interface to the camera sensor.

Comparison of non-IR lenses and IR lenses

Day and night cameras are generally used in near-infrared or infrared environments at night. If a lens without IR correction is used with a day-night camera, the camera will not be able to focus clearly when used at night. The EVETAR lens uses a glass lens with a special optical design and multi-layer coating to reduce light refraction to achieve optimal focus day and night. This way, the camera doesn't need to be refocused when used at night. CCD and CMOS image sensors utilize pixels arranged in a two-dimensional grid. These pixels convert optical images into electronic signals. The number of pixels on an image usually determines the resolution of the image, with more pixels meaning higher resolution. A megapixel means there are one million pixels. A megapixel camera is a camera that uses a megapixel sensor.

Matching a megapixel lens for a 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. Therefore, the quality of the optical image is a key factor affecting the overall image quality. The megapixel lens can provide high contrast, sharpness and sharpness to the entire image. Non-megapixel lenses, on the other hand, cannot fully express the high resolution of megapixel sensors, especially at the edges of the picture.