Image pickup apparatus with focus condition determination
In a case where an in-focus threshold value is set based on an F number, when a zoom or a focus is changed, the threshold value will change, so that an in-focus indication happens to be switched to an out-of-focus indication. To solve the problem, an image pickup apparatus has an image pickup unit that picks up an optical image formed through an optical system, wherein the optical system has a zoom function and F number thereof varies within a predetermined range according to a plurality of zoom conditions, a determination unit that determines an in-focus condition when a defocus amount of an object is smaller than predetermined first threshold value, wherein the first threshold value is determined by a minimum F number within the predetermined range, and a focus indication unit that indicates a first in-focus indication when the focus condition is in-focus condition.
1. An image pickup apparatus comprising:
an image pickup unit configured to pick up an optical image formed through an optical system, wherein the optical system has a zoom function and F number thereof varies within a predetermined range according to a plurality of zoom conditions;
one or more processors; and
a memory storing instructions which, when the instructions are executed by the one or more processors, cause the image pickup apparatus to function as:
a determination unit configured to determine a first in-focus condition in a case where a defocus amount of an object is smaller than a predetermined first threshold value, and to determine a second in-focus condition in a case where the defocus amount of the object is equal to or larger than the first threshold value and smaller than a second threshold value that is larger than the first threshold value, wherein the first threshold value is determined by a minimum F number within the predetermined range; and
a focus indication unit configured to indicate a first in-focus indication in a case where the determination unit determines that the focus condition is the first in-focus condition, and to indicate a second in-focus indication in a case where the determination unit determines that the focus condition is the second in-focus condition.
2. The image pickup apparatus according to claim 1 , wherein the optical system is included in a lens barrel that has an operation member for performing a focusing operation for focusing on an object by manually operating the optical system.
3. The image pickup apparatus according to claim 1 , wherein the optical system includes a zoom lens unit that can be detachably mounted to the image pickup apparatus, wherein the image pickup apparatus includes a communication unit for obtaining information on the minimum F number from the zoom lens unit.
4. The image pickup apparatus according to claim 1 , wherein the image pickup unit includes a defocus amount detection unit for detecting the defocus amount of the object by using a phase difference detection method.
5. The image pickup apparatus according to claim 1 , further comprising an autofocus unit configured to automatically perform a focusing operation.
6. The image pickup apparatus according to claim 5 , wherein the autofocus unit automatically performs the focusing operation if the focusing condition becomes an out-of-focus condition according to the change of the F number of the optical system after the determination unit determines the in-focus condition.
7. The image pickup apparatus according to claim 1 , further comprising another focus indication when the first in-focus indication or the second in-focus indication is not indicated.
8. The image pickup apparatus according to claim 7 , wherein a color of the first in-focus indication is the same as a color of the second in-focus indication, and is different from a color of said another focus indication.
9. The image pickup apparatus according to claim 1 , wherein the first threshold value is determined based on a product of a diameter of permissible circle of confusion δ and the F number.
10. The image pickup apparatus according to claim 9 , wherein the first threshold value is determined based on a product of an inverse number of a current F number and the minimum F number.
11. A non-transitory computer-readable recording medium storing a computer program for controlling an image pickup apparatus having an image pickup unit configured to pick up an optical image formed through an optical system, wherein the optical system has a zoom function and F number thereof varies within a predetermined range according to a plurality of zoom conditions, the computer program comprising:
a determination step for determining a first in-focus condition in a case where a defocus amount of an object is smaller than a predetermined first threshold value, and for determining a second in-focus condition in a case where the defocus amount of the object is equal to or larger than the first threshold value and smaller than a second threshold value that is larger than the first threshold value, wherein the first threshold value is determined by a minimum F number within the predetermined range; and
a focus indication step for indicating a first in-focus indication in a case where the determination step determines that the focus condition is the first in-focus condition, and for indicating a second in-focus indication in a case where the determination step determines that the focus condition is the second in-focus condition.