| 摘要 |
PURPOSE:To economize storage capacity without damaging accuracy by calculating an arithmetic coefficient from the data of a focusing distance and next calculating the moving amount of a focusing lens group from this arithmetic coefficient and the data of an object distance. CONSTITUTION:A focusing distance detecting means 4 detects the position of a magnification lens group 1 by using an encoder or the like and sends the output value of the focusing distance corresponding to this position to a first arithmetic means 5. The first arithmetic means 5 calculates two arithmetic coefficients by using two secondary expressions concerning the output value of the focusing distance and sends these two coefficients to a second arithmetic means 6. A distance measuring means 3 measures the object distance by using infrared rays, for example, and sends the value of the inverse to the second arithmetic means 6. The second arithmetic means 6 calculates the required moving amount of a focusing lens group 2 by using a secondary expression concerning the inverse value of the object distance and sends this moving amount to a focusing lens group driving means 7. |
