Camera

Abstract

A camera includes an imaging element that receives transmitted light of an imaging optical system, a calculator that calculates focus evaluation value responding to a focus status of the focus lens based upon an output of the imaging element, a scan driving that scans the focus lens in a single direction along an optical axis, a detector that detects an absolute position of the focus lens, a pitch determiner that determines a lens movement pitch deciding timing to obtain the focus evaluation value at a given interval in response to an output of the detector during the scan driving, a controller that obtains the focus evaluation value every time the focus lens moves by the determined lens movement pitch during the scan driving and a focusing adjuster that seeks a focus point by evaluating focus evaluation values obtained by the controller and drives the focus lens to the focus point.

What is claimed is:  
     
         1 . A camera comprising: 
 an imaging element that receives transmitted light of an imaging optical system including a focus lens,    a calculator that calculates focus evaluation value varying in response to a status of a focusing adjustment of the focus lens based upon an output of photoelectric conversion of the imaging element,    a scan driving that scans the focus lens in a single direction along an optical axis in obtaining a focus point,    a detector that detects an absolute position of the focus lens,    a pitch determiner that determines a lens movement pitch deciding timing to obtain the focus evaluation value at a given interval in response to a detection output of the detector during the scan driving,    a controller that obtains the focus evaluation value by activating the calculator every time the focus lens moves by the determined lens movement pitch during the scan driving and,    a focusing adjuster that seeks a focus point by evaluating a plurality of focus evaluation values obtained by the controller and drives the focus lens to the focus point.    
     
     
         2 . The camera set forth in  claim 1 , wherein, 
 in a case of the lens position detected by the detector being included in a given range, the pitch determiner makes the movement pitch small as compared to a case of the lens position being included in another range other than the given range.    
     
     
         3 . The camera set forth in  claim 2 , wherein 
 the given range is narrow in comparison to another range other than the given range.    
     
     
         4 . The camera set forth in  claim 2 , wherein 
 the given range is adjacent to a start or a finish point of the scan driving.    
     
     
         5 . The camera set forth in  claim 2 , wherein 
 the pitch determiner determines the movement pitch in response to the output of the detector and a focal length of the imaging optical system and the longer the focal length is, the smaller the movement pitch is made.    
     
     
         6 . The camera set forth in  claim 5 , wherein 
 the longer the focal length is, the narrower the given range is made.    
     
     
         7 . The camera set forth in  claim 2 , wherein 
 the pitch determiner determines the movement pitch in response to the output of the detector and f-number of the imaging optical system and the greater the f-number is, the larger the movement pitch is made.    
     
     
         8 . The camera set forth in  claim 7 , wherein 
 the greater the f-number is, the broader the given range is made.    
     
     
         9 . The camera set forth in  claim 1 , wherein, 
 in a case of the detected lens position being included in the given range, the pitch determiner makes the movement pitch large as compared to the case of the lens position being included in another range other than the given range.    
     
     
         10 . The camera set forth in  claim 1 , wherein 
 a close and long distance shooting modes are settable and    in the close distance shooting mode, in a case of the detected lens position being included in a given range at a close distance away, the pitch determiner makes the movement pitch small as compared to a case of the detected lens position being included in another range other than the given range at a close distance away and    in the long distance shooting mode, in a case of the detected lens position being included in a given range at a long distance away, the pitch determiner makes the movement pitch small as compared to a case of the detected lens position being included in another range other than the given range at a long distance away.    
     
     
         11 . The camera set forth in  claim 10 , wherein 
 the close distance mode includes a portrait and close-up shooting modes and the long distance mode includes a scenic and night scenery shooting modes.    
     
     
         12 . The camera set forth in  claim 1 , wherein 
 the scan driving scans the focus lens from either infinity end or a closest distance end to the other end.