Security surveillance lens field
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Serial number
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Item
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Value
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1
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EFL
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3.6
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2
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F/NO.
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2
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3
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FOV
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160°
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4
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TTL
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22.18
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5
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Sensor Size
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1/2.5”
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3.6mm short focal length security high-definition surveillance lens, 5 million pixel high-quality images, the first choice for high-definition surveillance and driving recorders. The lens of choice for China's top brands.
The above picture shows the intuitive understanding of the field of view of the long and short focal length lenses
EFL(effective focal length)
Relational formula: 1/u+1/v=1/f
Object distance: u Image distance: v Focal length: f
That is, the reciprocal of the object distance plus the reciprocal of the image distance equals the reciprocal of the focal length.
TTL(Total Track Length)
The total length of the lens is divided into total length of optics
and total length of mechanism.
Optical total length: refers to the distance from the first surface of the lens in the lens to the image surface. Shown as above picture, the TTL is 11.75mm
Total length of mechanism: refers to the distance from the end face of the lens barrel to the image plane.
MJOPTC can customize, research & develop related security surveillance lenses or provide OEM/ODM cooperation according to customer’s needs.
Four major factors that determine the imaging effect of the camera:
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Lens
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Aperture
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Image sensor
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Fill light
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Lens slide
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Resolution
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lamp
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Transmittance of light
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Light intake
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Pixel size
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Type
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Sensitivity
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Quantity Power
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Hardware
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Influence
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Ability symbol
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Lens
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Determines the rate of attenuation of light passing through the lens slide
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Light transmittance
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Aperture
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Determines the amount of luminous flux received by the camera at the same time
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Light entry capability
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Image sensor
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The larger the image sensor, the larger the pixels, and the stronger the photosensitive performance.
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Sensitivity
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Fill light lamp
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The type and number of fill lights determine the type of camera
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Fill light ability
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The first two parts of the above effects are determined by the lens
Note: The effect of the image is also closely related to the ISP tuning capability and the rationality of lens collocation
The commonly used working distance is about 50 times the focal length, so it is necessary to ensure that this distance has good aberration quality.
F/NO
Generally, the sensitivity of security cameras is relatively low. In the case of indoor lighting, the aperture of the lens can basically meet the requirements when used for F1.6~F3.8. Outdoor lighting is generally between F3.5~F10. Due to limited indoor space, lenses with focal lengths above 20mm are rarely used. From this point of view, for the lens within 20mm, it is very necessary to first ensure that the aperture around F1.6~F3.5 has better image quality.
For the lens with a focal length of more than 50 mm, It should first ensure that it has better image quality within the F8 aperture due to it is often used for outdoor daylight photography, otherwise, the F-number should even reach F1.0. because its lens mainly used for long-distance monitoring at night, Therefore, it is necessary to have good image quality under the condition of large relative aperture.
For day and night lenses, it is required to ensure image quality within a wider aperture range.
MJOPTC can customize, research & develop related security surveillance lenses or provide OEM/ODM cooperation according to customer needs.