Ads
related to: focal length and image distance calculator driving directions
Search results
Results From The WOW.Com Content Network
To render closer objects in sharp focus, the lens must be adjusted to increase the distance between the rear principal plane and the film, to put the film at the image plane. The focal length f, the distance from the front principal plane to the object to photograph s 1, and the distance from the rear principal plane to the image plane s 2 are ...
The original application called for placing the chart at a distance 26 times the focal length of the imaging lens used. The bars above and to the left are in sequence, separated by approximately the square root of two (12, 17, 24, etc.), while the bars below and to the left have the same separation but a different starting point (14, 20, 28, etc.)
The distance between an object and a lens. Real object Virtual object s i: The distance between an image and a lens. Real image Virtual image f: The focal length of a lens. Converging lens Diverging lens y o: The height of an object from the optical axis. Erect object Inverted object y i: The height of an image from the optical axis Erect image ...
For a given lens with the focal length f, the minimum distance between an object and the real image is 4f (S 1 = S 2 = 2f). This is derived by letting L = S 1 + S 2 , expressing S 2 in terms of S 1 by the lens equation (or expressing S 1 in terms of S 2 ), and equating the derivative of L with respect to S 1 (or S 2 ) to zero.
If the medium surrounding an optical system has a refractive index of 1 (e.g., air or vacuum), then the distance from each principal plane to the corresponding focal point is just the focal length of the system. In the more general case, the distance to the foci is the focal length multiplied by the index of refraction of the medium.
The effective focal length is nearly equal to the stated focal length of the lens (F), except in macro photography where the lens-to-object distance is comparable to the focal length. In this case, the absolute transverse magnification factor ( m ) ( m = S 2 / S 1 {\displaystyle m=S_{2}/S_{1}} ) must be taken into account:
The parameters = and = represent focal length in terms of pixels, where and are the inverses of the width and height of a pixel on the projection plane and is the focal length in terms of distance. [ 1 ] γ {\displaystyle \gamma } represents the skew coefficient between the x and the y axis, and is often 0.
where t is the total depth of focus, N is the lens f-number, c is the circle of confusion, v is the image distance, and f is the lens focal length. In most cases, the image distance (not to be confused with subject distance) is not easily determined; the depth of focus can also be given in terms of magnification m: = (+).