Choice of scenes to be considered a factor, the focal length
Lens focal length in millimeters of measurement units, it has been shot with the correlative observation angle. Small focal length lens with a large viewing angle, which has a long focal length lens with a long-term perspective and effect of the narrow observation angle. Usually eyes and observation angle lens similar to the standard known as the ordinary lens. COMPUTAR the slide rule is a focal length estimation, the object being to observe dimensions and tools to facilitate the perspective. In addition VM300 viewfinder is also used to select one of the focal length optical equipment.
2, camera specifications
Camera image sensor (CCD) Size also affects the viewing angle, using the same lens conditions, CCD smaller access angle smaller. On the specifications of the lens parameters of the request made it into images can image sensor (CCD) full coverage, such as : use the same specifications and the camera lens or camera specifications than the big shots. This is also thought to 1 / 3 of the camera specifications can be used 1/3-1 inches from the whole area of the lens, The camera matching 1 / 3 of 8mm camera with 2 / 3 of 8mm camera by the observation angle is the same. It is only because the use of the latter scenes as more use of more precise molding the lens optical center, So can provide better image quality and higher resolution.
3, the aperture value
Usually to the camera lens or aperture diameter value measurement, When fully opened when the lens is defined as the largest aperture (the smallest numerical aperture). lenses of the most effective caliber redeployment hours (not completely closed) for the definition of the smallest numerical aperture (maximum numerical aperture). Aperture value of the final image has many implications, a small numerical aperture, mean that the camera in a dark environment through more light, so that the camera can show a better image, in the high-brightness or reflection of the environment, with high numerical aperture of the lens will avoid Camera "whitening" Video stable level. All aperture automatically incorporated neutral opaque filter to increase the aperture value. Aperture value of depth of field has had a direct impact.
4, the depth of field
Observation of the region as a whole can be clearly within the scope of the imaging region has been defined as depth of field. Large depth of field from near the scene means that the observation of the target to the goal of Infinity observed in the overall region will be more regional - Xi imaging, the whole region is usually * close-ups from the observation of the infinite targets. Depth means that only a small part of the district can be less clear imaging. Depth of field size by many factors, usually wide-angle lenses than telephoto lenses with a greater depth of field. large aperture value with a large depth of field range. For automatic aperture lens, aperture constantly adjust the depth of field size also means that the corresponding changes All night automatic aperture is opened, the depth of field scope at this time to achieve its minimum, It also means clear during the day to observe the target this time is likely to become blurred.
5, automatic and manual aperture
Normally, we tend to change in light of the large outdoor use automatic aperture lenses, Ray remained in constant use in indoor places manual aperture lens. With the camera with an electronic shutter can conduct electronic compensation. can now also in the light of changes to use manual aperture lenses, But for such use some form of factors need to be considered, the numerical aperture settings has become more stringent, If the camera for night work can be opened to the largest aperture, depth of field will be made very small. even in the daytime to have difficulty obtaining clear images, although the camera can maintain output level of stability, but not corresponding to maintain the depth of field size. To increase the depth of field, if they locked small aperture, the camera in a dark environment performance will be much less.
6, video-drive and direct drive
Automatic aperture lens to control the aperture through the operation to achieve the best image results. Video-driven automatic aperture lens to enlarge -- intron rate, the camera can be converted video signal so as to control the aperture. Direct-drive automatic aperture of the lens, only with the galvanometers-aperture motors, the prices are cheaper video-driven, But they require the use of the cameras to be embedded amplifier. Choice of two automatic aperture lens it is based on the use of what the camera is automatic aperture driven forms, usually present circumstances with two cameras were driven form.
7, C-type interface and CS
The camera and lens are usually CS-type interface, CS-camera and can type C and CS-shot match Then, once the scene of the C-type matching, in the camera lens and then increase between 5 mm then assigned to the Central get a clear image. C-type interface with the camera not CS-shot match Next, because it is physically impossible to make shots close to the CCD image to get a clear