Stop drive control device, operation method of stop drive control device, operation program of stop drive control device, and imaging apparatus

1 . A stop drive control device comprising:

a processor,

wherein the processor is configured to:

perform drive control of a stop opening degree adjustment mechanism that adjusts an opening degree of a stop, based on opening degree history information stored in a storage unit and comprising a plurality of records, each record including a target opening degree of the stop and a current opening degree of the stop, the drive control being in accordance with a fluctuation of a focal length of a zoom lens during operation of the zoom lens; and

for each frame sequentially output by an imaging element, store in the storage unit a record associating the target opening degree with the current opening degree as part of the opening degree history information.

2 . The stop drive control device according to claim 1 ,

wherein the target opening degree is determined in accordance with focal length information obtained during operation of the zoom lens, and

the processor is configured to:

perform the drive control during operation of the zoom lens based on the opening degree history information.

3 . The stop drive control device according to claim 1 ,

wherein the processor is configured to:

in a case where records for frames set in advance tracing back from a current frame are not stored in the opening degree history information, perform the drive control based on the target opening degree and the current opening degree derived in the current frame; and

in a case where records for frames set in advance tracing back from a current frame are stored in the opening degree history information, perform the drive control based on the opening degree history information.

4 . The stop drive control device according to claim 3 ,

wherein the processor is configured to:

in a case where there is a difference between the target opening degree and the current opening degree of the records for frames set in advance tracing back from the current frame and there is no change in the target opening degree of the records for frames set in advance tracing back from the current frame,

suppress the drive of the stop opening degree adjustment mechanism.

5 . The stop drive control device according to claim 3 ,

wherein the processor is configured to:

in a case where there is a difference, which is equal to or less than a first threshold value set in advance, between the target opening degree and the current opening degree of the records for frames set in advance tracing back from the current frame and there is a change in the target opening degree of the records for frames set in advance tracing back from the current frame by a change amount equal to or less than a second threshold value set in advance,

increase driving force applied to the stop from the stop opening degree adjustment mechanism.

6 . The stop drive control device according to claim 3 ,

wherein the processor is configured to:

in a case where there is a difference, which is equal to or larger than a third threshold value set in advance, between the target opening degree and the current opening degree of the records for frames set in advance tracing back from the current frame and a difference between the target opening degree and the current opening degree of the record of a previous frame of the current frame is reversed in sign with a difference between the target opening degree and the current opening degree of the record of the current frame,

decrease driving force applied to the stop from the stop opening degree adjustment mechanism.

7 . The stop drive control device according to claim 3 ,

wherein the processor is configured to:

derive a predicted value of a difference between the target opening degree and the current opening degree of a frame next to the current frame based on the opening degree history information.

8 . The stop drive control device according to claim 7 ,

wherein the processor is configured to:

in a case where there is a change in the target opening degree of the records for frames set in advance tracing back from the current frame by a change amount equal to or less than a fourth threshold value set in advance and a difference between the target opening degree and the current opening degree of the record of the current frame is not reversed in sign with the predicted value,

increase driving force applied to the stop from the stop opening degree adjustment mechanism.

9 . The stop drive control device according to claim 7 ,

wherein the processor is configured to:

in a case where there is a change in the target opening degree of the records for frames set in advance tracing back from the current frame by a change amount equal to or less than a fifth threshold value set in advance and a difference between the target opening degree and the current opening degree of the record of the current frame is reversed in sign with the predicted value,

decrease driving force applied to the stop from the stop opening degree adjustment mechanism.

10 . The stop drive control device according to claim 7 ,

wherein the processor is configured to:

in a case where a difference between the target opening degree and a current opening degree is equal to or larger than a sixth threshold value set in advance, drive the stop opening degree adjustment mechanism to set the current opening degree to the target opening degree; and

in a case where the difference is less than the sixth threshold value, maintain the current opening degree without driving the stop opening degree adjustment mechanism.

11 . The stop drive control device according to claim 7 ,

wherein the processor is configured to:

change driving force applied to the stop from the stop opening degree adjustment mechanism according to an operation speed of the zoom lens.

12 . An imaging apparatus comprising:

the stop drive control device according to claim 1 .

13 . An operation method of a stop drive control device comprising:

for each frame sequentially output by an imaging element, storing, in a storage unit, a record associating a target opening degree of a stop with a current opening degree of the stop as part of opening degree history information comprising a plurality of records; and

performing drive control of a stop opening degree adjustment mechanism that adjusts an opening degree of a stop, based on the opening degree history information, the drive control being in accordance with a fluctuation of a focal length of a zoom lens during operation of the zoom lens.

14 . A non-transitory computer-readable storage medium storing an operation program of a stop drive control device causing a computer to execute a process comprising:

for each frame sequentially output by an imaging element, storing, in a storage unit, a record associating a target opening degree of a stop with a current opening degree of the stop as part of opening degree history information comprising a plurality of records; and

performing drive control of a stop opening degree adjustment mechanism that adjusts an opening degree of a stop, based on the opening degree history information, the drive control being in accordance with a fluctuation of a focal length of a zoom lens during operation of the zoom lens.