Picture taking apparatus having focusing device

Abstract

A plurality of distance measuring points in a picture can be correctly and rapidly focused on. Images at a plurality of distance measuring points in the picture can be detected through a photographing lens by means of an image pickup element. These detected distance measuring points can be displayed on a monitor screen. Finally, a photographing lens can be controlled with respect to the displayed distance measuring points so as to cause the output from the image pickup element to reach its highest contrast.

1 . A picture taking apparatus capable of focusing on one of a plurality of distance measuring points in a picture for photography, comprising: 
 a focus detecting device capable of obtaining distance information of each of the plurality of distance measuring points;    a control section for controlling a photographing operation of the apparatus to select one distance measuring point from the plurality of distance measuring points by using the distance information obtained by the focus detecting device and to display the selected distance measuring point on a display member; and    a focusing device capable of focusing a subject lying at the selected distance measuring point to maximize the contrast of an image of the subject.    
     
     
         2 . A focusing method for use with a picture taking apparatus capable of focusing on one of a plurality of distance measuring points in a picture for photography, comprising: 
 selecting one distance measuring point from the plurality of distance measuring points by using an image signal of a subject or distance information on the subject;    displaying an indicator of the selected distance measuring point in such a manner as to superimpose the indicator on a subject image;    accepting an input change signal for changing the distance measuring point;    changing the displayed distance measuring point to another distance measuring point in response to the change signal; and    focusing a subject lying at the other distance measuring point to maximize the contrast of an image of the subject, wherein the steps of accepting an input change signal and changing the displayed distance measuring point are performed before any focusing on the initially selected distance measuring point.    
     
     
         3 . A picture taking apparatus comprising: 
 a photographing lens;    an image pickup section including an image pickup element for acquiring an image signal representative of a subject through the photographing lens;    a selecting section for selecting one distance measuring point from a plurality of distance measuring points in a picture for photography in accordance with a first manipulation of a release switch;    a display section having a display screen for displaying an image of a subject and an indicator of the distance measuring point selected by the selecting section;    a change instructing member;    a changing section for changing the distance measuring point selected by the selecting section to another distance measuring point in response to a manipulation of the change instructing member;    a control section for detecting a contrast value of a subject image lying at the distance measuring point determined by the selecting section or the other distance measuring point changed to by the changing section in response to a second manipulation of a release switch;    an auto-focus section for controlling a focus state of the photographing lens based on a contrast value detected by the control section; and    an exposure section for recording an image signal output from the image pickup section.    
     
     
         4 . A picture taking apparatus having an auto-focusing device recited in  claim 3 , wherein the selecting section includes a main subject determining section for determining a main subject based on the image signal output from the image pickup section, wherein the distance measuring point is selected based on the determined main subject.  
     
     
         5 . A picture taking apparatus recited in  claim 4 , wherein the main subject determining section determines the main subject from at least one of color information and pattern information of areas corresponding to the plurality of distance measuring points of the image signal output from the image pickup section.  
     
     
         6 . A picture taking apparatus recited in  claim 3 , wherein the selecting section includes a distance detecting device for detecting subject distances of the plurality of distance measuring points, respectively, wherein the distance measuring point is selected based on a detected subject distance.  
     
     
         7 . A picture taking apparatus recited in  claim 3 , wherein the display section changes a display position of the indicator on the display screen based on a changing manipulation of the change instructing member.  
     
     
         8 . A picture taking apparatus recited in  claim 3 , wherein the auto focus section includes a hill-climbing auto-focus type of focusing device.  
     
     
         9 . A picture taking apparatus recited in  claim 3 , wherein the display section includes a magnifying display section for displaying at a magnified scale an area corresponding to the distance measuring point after a focusing operation has been performed by the auto focus section.  
     
     
         10 . A picture taking apparatus comprising: 
 a photographing lens;    an image pickup element for picking up a subject image through the photographing lens and outputting an image signal;    a photographing lens driving mechanism for driving the photographing lens;    a determining unit for determining contrast values of the subject image in a plurality of areas on the image pickup element that correspond to a plurality of distance measuring points in a picture for photography;    a changing switch for outputting a change signal indicative of an input to change a distance measuring point; and    a controller which, at a first timing, selects one distance measuring point from among the plurality of distance measuring points, and when the controller receives the change signal, changes the distance measuring point selected at the first timing, and, at a second timing, controls a focusing operation of the photographing lens based on an output from the determining circuit for an area corresponding to the selected or changed distance measuring point.    
     
     
         11 . A picture taking apparatus recited in  claim 10 , further comprising a display capable of displaying the image signal and an indicator of the distance measuring point.  
     
     
         12 . A picture taking apparatus recited in  claim 11 , wherein the display is controllable to display at a magnified scale an area corresponding to the distance measuring point.  
     
     
         13 . A picture taking apparatus recited in  claim 10 , wherein the first timing is an input timing for a first release signal responding to a partial depression of a release switch, and the second timing is an input timing for a second release signal responding to a further depression of the release switch.  
     
     
         14 . A picture taking apparatus comprising: 
 means for acquiring an image of a subject and outputting an image signal;    means for determining, at a first time a main subject in a picture for photography from the image signal representative of the image acquired by the image pickup means and for selectively determining a distance measuring point based on a position where the main subject exists;    display means for displaying the image acquired by the means for acquiring and an indicator of the distance measuring point selected by the means for determining;    means for changing the distance measuring point selected by the means for determining to another distance measuring point based on an external instruction; and    means for detecting, at a second time, a contrast value of an area corresponding to the distance measuring point that is determined in the image signal acquired by the means for acquiring, by the means for determining or by the means for changing, and for controlling focusing of the apparatus based on a detected result.    
     
     
         15 . A picture taking apparatus comprising: 
 a photographing lens;    an image pickup element for acquiring an image of a subject through the photographing lens and outputting an image signal;    a photographing lens driving mechanism for driving the photographing lens;    a distance measuring unit for performing distance measurement at a plurality of distance measuring points in a picture for photography;    a determining unit capable of determining contrast values of the subject image in a plurality of areas on the image pickup element that correspond to a plurality of distance measuring points in a picture for photography;    a changing.switch for outputting a change signal indicative of an instruction to change a distance measuring point; and    a controller which, at a first time, selects one distance measuring point from among the plurality of distance measuring points based on an output from the distance measuring unit, and when the controller receives the change signal, changes the distance measuring point selected at the first time, and, at a second time,    controls a focusing operation of the photographing lens based on an output from the contrast determining unit for an area corresponding to the selected or changed distance measuring point.    
     
     
         16 . A picture taking apparatus recited in.  claim 15 , further comprising a display capable of displaying the subject image and a mark representative of the distance measuring point.  
     
     
         17 . A picture taking apparatus recited in  claim 16 , wherein the display is controllable to display at a magnified scale a subject lying in the plurality of areas.  
     
     
         18 . A picture taking apparatus recited in  claim 15 , wherein the first time is an input time for a first release signal responding to a partial depression of a release switch, and the second time is an input timing for a second release signal responding to a further depression of the release switch.  
     
     
         19 . A picture taking apparatus comprising: 
 means for acquiring an image signal;    means for performing distance measurement at a plurality of distance measuring points in a picture for photography;    means for selecting a distance measuring point where a main subject exists, at a first time based on an output from the means for performing;    means for displaying the image acquired by the means for acquiring and an indicator of the distance measuring point selected by the means for. selecting;    means for changing the distance measuring point selected by the means for selecting to another distance measuring point responsive to an external instruction; and    means for, at a second time, detecting a contrast value of an area corresponding to the distance measuring point that is determined by the means for selecting or by the means for changing by using the image signal acquired by the means for acquiring, and for controlling an focus state of the photographing lens based on a detected result.    
     
     
         20 . A focusing method comprising: 
 determining a main subject in picture for photography;    setting a position of the main subject as a distance measuring point;    displaying the set distance measuring point;    determining whether-the distance measuring point set-is to be changed; and    executing a hill-climbing auto-focusing operation, if it is determined that the distance measuring point set is not to be changed, on the distance measuring point set, and, if it is determined that the distance measuring point is to be changed, on the distance measuring point changed on the basis of a determined result.    
     
     
         21 . An auto-focusing device comprising: 
 means for detecting images at a plurality of points in a picture;    means for selecting one distance measuring point from the plurality of distance measuring points based on a result detected by the means for detecting, and for displaying an indicator associated with the selected distance measuring point; and    means for controlling a photographing lens to a subject corresponding to the distance measuring point displayed so as to cause an output from the means for detecting to reach its highest contrast.    
     
     
         22 . An auto-focusing device recited in  claim 21 , further comprising means for changing the distance measuring point responsive to a manual manipulation before or during an operation of the means for controlling.  
     
     
         23 . A picture taking apparatus comprising: 
 an image pickup section for detecting an image signal of a subject; and    a display section for displaying an image of the subject, the display section having a first display mode for a subject image detected by the image pickup section and an indicator of a position of a target to be focused, and a second display mode for displaying a magnified image of the target to be focused.    
     
     
         24 . A picture taking apparatus recited in  claim 23 , further comprising a photographing lens, wherein the display section performs its display operation in the first display mode before a focusing operation of the photographing lens, and performs its display operation in the second display mode after the focusing operation of the photographing lens.  
     
     
         25 . A picture taking apparatus comprising: 
 means for measuring distances of subjects respectively existing at a plurality of distance measuring points in a picture for photography, through an optical path different from a photographing lens;    means for acquiring an image signal representative of an image of a subject in the picture through the photographing lens;    means for focusing the photographing lens based on an output from the means for acquiring; and    means for controlling an operation displaying distance measuring points at which distances have respectively been measured by the distance means for measuring, in a viewfinder at a first time before photography, and for controlling the focusing of the photographing lens by the means for focusing by using image signals corresponding to the distance measuring points, at a second time different from the first time.    
     
     
         26 . A picture taking apparatus comprising: 
 a distance measuring unit for measuring distances at a plurality of points in a picture through an optical path different from a photographing optical path, and selecting one point from the plurality of points;    a display unit for displaying an indicator associated with the point selected by the distance measuring unit;    a changing switch for changing a position of the indicator displayed on the display;    a photographing lens;    an image pickup element for acquiring a subject image through the photographing lens and outputting a subject image signal;    a determining circuit for determining a contrast of the subject image signal outputted from the image pickup element; and    a control unit for focusing the photographing lens to a subject lying at the point displayed on the display screen, so as to cause an output from the image pickup element to reach its highest contrast.    
     
     
         27 . A picture taking apparatus comprising: 
 means for detecting images at a plurality of points in a picture for photography;    means for selecting one point from the plurality of points based on a result detected by the means for detecting;    means for controlling a photographing lens to focus the point selected by the means for selecting, so as to cause an output from the means for detecting to reach its highest contrast; and    means for displaying the selected point and an image surrounding the selected point, after an operation of the means for controlling.