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The method of parameter type selecting of camera lens
From;    Author:Stand originally
If compare camera,be the person's eye, camera lens is just like is eyeball, it matters to inspect to see the far and near of the object, limits and effect directly. Of camera lens choose Lv of take an examination when:

1) camera lens dimension should is equal to or be more than camera to become measure resembling an area. For example: 1/3 ″ camera is optional 1 ″ of 1/3 ″ ~ is whole the camera lens inside limits, but the size of horizontal perspective is same. Just use the camera lens that is more than 1/3 ″ to be able to use take shape morely, more accurate smooth road of camera lens center, can raise picture quality and resolution so.

2) choose right camera lens focus. Focus is bigger, inspect sees a space further, horizontal perspective is less, surveillant range is narrower; Focal length is smaller, inspect sees a space closer, horizontal perspective is bigger, surveillant range is wider. Camera lens focal length but according to the following and formulary estimation.

F=A × L/H
(F- - camera lens focal length; A- - camera CCD hangs down to dimension; L- - the object that be photographed is apart from to camera lens; H- - height of the object that be photographed)

  of   of case   type 2/3 of 1 inch of   inch   1/2 inch   1/3 inch 1/4 inch

CCD hangs down to dimension   6.6 ㎜ of   of 9.6 ㎜   4.8 ㎜ of     3.6 ㎜ of     2.7 ㎜ of      

3) the change that considers ambient light line. The radial collection to image is worn since the effect very main effect. Generally speaking, to the environment with radial not apparent change, we often choose a hand to use aperture camera lens, after comparing aperture hand attune good numerical value to, can not move; If radial change is bigger, if 24 hours of inspect outdoor look, should choose automatic aperture, can change according to radial light and shade the size that self-adjusting aperture is worth, assure picture quality. But those who require an attention is, if radial intensity of illumination is inhomogenous, monitor especially when target and contrast of bias light compensation are bigger, use effect of automatic aperture camera lens not ideal.

4) consider optimal inspect to treat range. Because camera lens focal length and horizontal perspective become inverse ratio, because this wants to look far already, want to look again expanse and clarity, this cannot come true at the same time. The camera lens of every focal length can achieve first-rate inspect to see the effect inside certain limits only, so if inspect looks the distance is further and range is bigger, had better be the amount that increases camera, or use dynamoelectric scorch camera lens to cooperate cloud stage installation.

5) camera lens interface and camera interface should agree. Present camera and camera lens are CS interface normally, CS camera can be mixed CS, C camera lens deserves to receive, but receive with C camera lens when matching, must add between camera lens and camera receive match annulus, touch bad CCD possibly to protect glass into what resemble an area otherwise, cause the damage of CCD camera. C camera cannot deserve to receive with CS camera lens.
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