Image pickup apparatus for varying filter characteristics for focus adjustment

Claim 2

An image pickup apparatus comprising: image pickup means; filter means for extracting, from an image signal outputted from said image pickup means, a high-frequency component which varies according to a state of focusing as a focus evaluating value; luminance detecting means for detecting a luminance level different from the high-frequency component in the image signal; and control means for varying a frequency passband of said filter means according to the luminance level detected by said luminance detecting means.

Claim 3

An image pickup apparatus according to claim 1 , wherein said control means is arranged to vary a high cut-off frequency of said filter means.

Claim 4

An image pickup apparatus according to claim 2 , wherein said control means is arranged to shift the high cut-off frequency of said filter means to a higher frequency when the luminance level is found to be high indicating a high luminance object.

Claim 5

An image pickup apparatus according to claim 3 , wherein said filter means has a low-pass filtering characteristic.

Claim 6

An image pickup apparatus according to claim 1 , wherein said filter means is composed of a plurality of filters, which have different frequency passbands and include a high-pass filter and a low-pass filter.

Claim 7

An interchangeable lens type camera comprising: image pickup means; filter means for extracting, from an image signal outputted from said image pickup means, a high-frequency component which varies according to a state of focusing; luminance detecting means for detecting information on a luminance level in the video signal; and control means for transmitting an output of said filter means and an output of said luminance detecting means to a lens unit, and for varying a characteristic of said filter means according to predetermined information supplied from said lens unit.

Claim 8

An interchangeable lens type camera comprising: image pickup means; filter means for extracting, from an image signal outputted from said image pickup means, a high-frequency component which varies according to a state of focusing; luminance detecting means for detecting information on a luminance level in the video signal; and control means for transmitting an output of said filter means and an output of said luminance detecting means to a lens unit, and for varying a characteristic of said filter means according to predetermined information supplied from said lens unit.

Claim 9

An interchangeable lens type camera according to claim 6 , wherein said control means is arranged to shift the high cut-off frequency of said filter means to a higher frequency when the luminance level is found to be high indicating a high luminance object.

Claim 10

An interchangeable lens type camera according to claim 7 , wherein said filter means is a low-pass filter.

Claim 11

A lens unit detachably mountable on a camera body, comprising: focus detecting means for detecting a state of focusing by receiving, from said camera body, information on a high-frequency component extracted from a video signal by filter means disposed at said camera body; and filter control means for transmitting, to said camera body, a filter control signal for varying a characteristic of said filter means of said camera body, on the basis of information on a luminance level received from said camera body.

Claim 12

A lens unit detachably mountable on a camera body, comprising: focus detecting means for detecting a state of focusing by receiving, from said camera body, information on a high-frequency component extracted from a video signal by filter means disposed at said camera body; and filter control means for transmitting, to said camera body, a filter control signal for varying a characteristic of said filter means of said camera body, on the basis of information on a luminance level received from said camera body.

Claim 13

A lens unit according to claim 9 , wherein said filter control means is arranged to shift the high cut-off frequency of said filter means to a higher frequency when the luminance level is found to be high indicating a high luminance object.

Claim 14

A lens unit according to claim 10 , wherein said filter means is a low-pass filter.

Claim 15

A focus detecting method, comprising: extracting step of extracting by filter means, from an image signal outputted from image pickup means, a high-frequency component which varies according to a state of focusing as a focus evaluating value; luminance detecting step of detecting a luminance level different from the high-frequency component in the image signal; and control step of varying a frequency passband of said filter means according to the luminance level detected in said luminance detecting step.

Claim 16

A focus detecting method, comprising: extracting step of extracting by filter means, from an image signal outputted from image pickup means, a high-frequency component which varies according to a state of focusing as a focus evaluating value; luminance detecting step of detecting a luminance level different from the high-frequency component in the image signal; and control step of varying a frequency passband of said filter means according to the luminance level detected in said luminance detecting step.

Claim 17

A method according to claim 12 , wherein said control step is arranged to vary a high cut-off frequency of said filter means.

Claim 18

A method according to claim 13 , wherein said control step is arranged to shift the high cut-off frequency of said filter means to a higher frequency when the luminance level is found to be high indicating a high luminance object.

Claim 19

A method according to claim 14 , wherein said filter means is a low-pass filter.

Claim 20

A method according to claim 12 , wherein said filter means is composed of a plurality of filters, which have different frequency passbands and include a high-pass filter and a low-pass filter.