A mechanical adjustment in a camera that moves the imaging device relative to the lens to compensate for different focal lengths of lenses. This is important when a zoom lens is fitted.
Critical adjustment on located at rear of HD telephoto lens to ensure sharp focus.
When the lens is focused at infinity, the distance from the rear surface of the lens to the focal plane is called BACK FOCUS.
Cameras are focused by moving the image sensor in relationship with the lens, which enables differing back focal lengths for the lens. This adjustment is called Back Focus and is important when fitting a zoom.
When a lens does not hold focus at both ends of the zoom range, you may need to adjust the back focus. By adjusting the back focus, you are changing the distance of between the pick-up device and the rear element of the lens. Technically, it's the distance from the vertex of the rearmost element of the lens to the focal plane. In most cases, changing a lens will not require adjusting the back focus.
A fine mechanical adjustment in the camera which moves the CCD chip or the lens mount to ensure the chip is placed at the exact focal point of the lens
This is the alignment of the rear of the lens to the imaging device
A physical repositioning of the CCD, the camera element that translates light into electronic pulses for recording on videotape. The effect is to lengthen or shorten the distance between the lens and the CCD.
The distance from the rear-most portion of the lens element to the image plane. It is important to adjust the back focus correctly in order to obtain the best image. Certain lenses come with a back focus adjustment mechanism, while others do not. Also, most of the cameras incorporate back focus adjustment, if it is not available on the lens side.
The mechanical aligning of the imaging device with the focal point of the lens. Most important on zoom lenses to ensure the image stays in focus throughout the zoom range.
Adjusting the distance between the back of a lens and the camera target to attain the sharpest image possible of an object at infinity. Back focus adjustment determines whether a zoom lens will stay in focus when moved through its focal length range.
The mechanical adjustment on a camera that varies the relative distance between the imaging device and the rear lens element. This is an important adjustment that needs to be set correctly when lens is first fitted to a camera, it is particularly important when a zoom lens is fitted.
A situation where the lens is actually focused behind the main subject, resulting in a slight softness of that subject. Back focus is a common problem when there is another object behind the main subject and the autofocus locks onto it instead.
Distance between the back surface of the lens and the image plane, when the lens is focused at infinity.
Back focus is a term used to describe the relationship of the distance of the lens to the image device. This distance is critical to maintain the proper depth of field through changing focal lengths and varying light conditions. The correct back focus is normally achieved by adjusting the image pick-up device on the camera itself.