Resources

A

B

C

D

E

F

G

I

L

M

R

V

Z

A

Angle of view

In case focusing to far, Angle of view means the angle for imaging of the horizontal and vertical in image size. W=2tan-1(Φ/2*f)

Aspherical Lens

In theory, spherical lens never focus into one point on optic axis. By improving the geometry of spherical lens , Aspherical lens realize to focus into one point.

B

Back Focus

The length from vertex of last lens to focal point. In case too short of bach focus raise to interfere filter in camera.

C

Close-up lens

As M.O.D. of the ordinary zoom lens is over 1m, in case the demanded object distance is under 1m, close-up lens solve the problem.

Coating

Coating is for contoling of reflection of ray at surface of lens. Under vaccum, MgF2 is heated up by electric beam and coat on the lens.

C-Mount

The flange back is 17.526 mm

Cromatic Aberration

The refractive index is different from according to the wave length. The Chromatic aberration occur by it.

There are 2 kinds of the cromatic aberration, one is Longitudinal chromatic aberration, other is Lateral chromatic aberration.

CS-Mount

The flange back is 12.5 mm

D

Diffraction

Ray has the characteristic features that sneak aroud to behind of Iris. Then blurring occurs when the iris become to small.

Distortion

real image point is off from the ideal image point because of aberration. The budget means distortion.

DC-IRIS

One of the way of Auto-Iris. Best bightness will be kept automatically by Iris control signal from camera.

Day & Night lens

The focal point of visible ray and IR ray are not same position. Therefore even if adjustment focus under visible ray, the focal point dose shift under IR ray.

Depth of field

Even if under out of focus, in range that it is not found as out of focus, it is regarded in focus. Such this range means Depth of field.

E

ED Glass

Extra low Dispersion Glass. Ordinary glass disperse its color according to the wave length but ED Glass can inhibit to the dispersion.

Extender

Extender is one of rear conversion lens. It makes the focal length of master lens long. In case of 2 x Extender, the focal length become 2 times but F No. drops 2 stops. It means that the brightness become 1/4.

F

F number

F NO. means the brightness of the lens. Small F NO. is bright lens. F NO. = f/D

Fish eye Lens

The lens which angle of view is 180 degrees. Like fish eye is called Fisheye Lens. There is shading at the corner of monitor.

Focal point

When palallel ray is entered into lens, there is a point that the ray gather into one point on optical axis.

It means focal point.

Focal length

The distance from center of lens to the focal point.

Focus shifting

Phonomenon that becoming out of focus under IR ray although focused under visible ray. Because of the difference focus point under visible ray and IR ray.

Flange Back

The length from reference point of mounting lens to focal point.

Focus

Function of lens that bring into focus.

G

Ghost

Ray reflect inside lens or on face of sensor and the image that is different from fact appear on the monitor.

I

IR Cut Filter

IR Cut Filter shadow IR light.

Iris

Diaphragm of lens. Mechanism for adjustment for brightness of image.

Iris Control

For adjustment for brightness, Iris be controled into open or close.

Image Size

The image formation of lens is circle. 1": 12.8 x 9.6 mm (16φ), 2/3": 8.8 x 6.6 mm (11φ), 1/2": 6.4 x 4.8 mm (8φ), 1/3": 4.8 x 3.6 mm (6φ)

L

Lateral chromatic aberration

Refractive index is different from by wave length and in case of becoming longitudinal chromatic aberration big,

the image of color blur.

Longitudinal chromatic aberration

IR Cut Filter shadow IR light.

Light Distribution

The rate of brightness of corner compared with center means vignetting.

M

M.O.D.

Minimum Object distance. Within M.O.D., the focus cannot adjust.

MTF

Modulation Transfer Function. The recall rate of contrast.

Mount

The part which fix with lens and camera.

Megapixel

lens

Ordinary lens is designed its resolution for 400,000 pixel sensor. Megapixel lens is designed for over 1,000,000 pixel cameras. The resolution is quite diferent.

R

Resolution

Resolution is one of performance of image formation. When imaging test chart, confirming how lens resolution can perform.

Refractive

index

After ray enter lens, the angle of pass means Refraction index.

R

Vari Focal

Lens

Vari Focal Lens is a small and conpetitive lens and able to adjust its focal length. But every time focal length is changed, focus adjustment should be neccesarry.

Video Iris

One of the way of Auto-Iris. There is an electric eye circuit board inside lens and be supplied video signal from camera, best bightness should be keeped automatically.

Z

Zoom

Zoom is able to keep the focus during changing the focal length.

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