Depth of field controlling by focus point

Abstract

A camera having a depth of field which can be modified to produce desired photographic effects. The camera determines the depth of field for a subject when the subject is focused upon. A modification to the depth of field is determined based upon the distance to the subject, and the depth of field is modified to produce the desired photographic effect. In one embodiment, the depth of field is reduced, while, in another embodiment, the depth of field is shifted to place the subject slightly out of focus and to alter the focus of the background.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional side view of a generic digital camera constructed according to the principles of the present invention;

FIG. 2 is a perspective view of a mobile telephone that can be used in the implementation of the present invention;

FIG. 3 is a schematic representation of the telephone circuitry of the mobile telephone of FIG. 2;

FIG. 4 is a flow diagram showing a generic process for the implementation of the present invention;

FIG. 5 is a flow diagram showing a process utilized by one embodiment for modifying the depth of field;

FIG. 6A is an illustration the standard depth of field;

FIG. 6B is an illustration of a reduced or shallow depth of field in accordance with the principles of the present invention; and

FIG. 6C is an illustration of a shifted depth of field in accordance with the principles of the present invention.

Claims

1. A method for controlling depth of field of a camera having a memory unit, comprising: ascertaining a distance from the camera to a subject;automatically determining a change for modifying the depth of field with respect to the subject; andimplementing the determined change for modifying the depth of field, wherein the depth of field is modified as a result of the implemented change.

2. The method of claim 1, wherein the change comprises refocusing at a point other than the subject, wherein the depth of field moves with regard to the subject.

3. The method of claim 2, wherein the moving the focus point comprises placing the subject ⅓ from a front of the depth of field.

4. The method of claim 1, wherein the change comprises altering the size of the depth of field.

5. The method of claim 1, further comprising determining whether the camera is in a “modify depth of field” mode, and wherein the determining and the implementing of the change occurs only if the camera is in the modify depth of field mode.

6. The method of claim 1, further comprising, prior to ascertaining the distance from the camera to the subject, focusing on the subject.

7. The method of claim 6, further comprising locking the lens position to prevent subsequent refocusing on the subject following the implementation of the change in the field of depth.

8. The method of claim 2, further comprising, prior to capturing an image of the subject and after the depth of field is modified, providing an image preview of the subject.

9. The method of claim 1, wherein the automatically determination of the change involves the use of a look-up-table.

10. The method of claim 9, wherein the look-up table is stored in the memory unit.

11. The method of claim 1, wherein the distance associated with an image is determined using position sensors associated with a lens system

12. The method of claim 11, wherein a value determined for the distance is stored in the memory unit.

13. A computer program product for controlling depth of field of a camera, comprising: computer code for determining the depth of field for a subject;computer code determining via a look-up-table, which is stored in the memory unit, a change for modifying the depth of field with respect to the subject; andcomputer code for implementing the determined change for modifying the depth of field.

14. The computer program product of claim 13, wherein the change comprises moving the focus point to a point other than the subject wherein the depth moves with regard to the subject.

15. The computer program product of claim 14, wherein the moving the focus point comprises placing the subject ⅓ from a front of the depth of field.

16. The computer program product of claim 13, further comprising computer code for determining whether the camera is in a “modify depth of field” mode, and wherein the determining and the implementing of the change occurs only if the camera is in the modify depth of field mode.

17. The computer program product of claim 13, wherein the change comprises altering the size of the depth of field.

18. The computer program product of claim 14, further comprising computer code for, prior to ascertaining a distance from the camera to the subject, focusing on the subject and computer code for locking the lens position to prevent subsequent refocusing on the subject following the implementation of the change in the field of depth.

19. The computer program product of claim 14, further comprising computer code for storing in the memory unit the distance associated with an image.

20. An electronic device, comprising: a processor for processing information;a memory unit operatively connected to the processor; anda digital camera,wherein the memory unit includes: computer code for ascertaining a distance from the camera to a subject;computer code for determining via a look-up-table, which is stored in the memory unit, a change for modifying the depth of field with respect to the subject; andcomputer code for implementing the determined change for modifying the depth of field.

21. The electronic device of claim 20, wherein the electronic device includes a digital camera comprising part of a camera-phone.

22. The electronic device of claim 21, wherein the digital camera comprises a charge coupled device.

23. The electronic device of claim 21, wherein the memory unit further comprises computer code for refocusing at a point other than the subject wherein the depth moves with regard to the subject.

24. The electronic device of claim 21, wherein the memory unit further comprises computer code for altering the size of the depth of field.

25. The electronic device of claim 21, wherein the memory unit further comprises computer code for, prior to ascertaining the distance from the camera to the subject, focusing on the subject and computer code for locking the lens position to prevent subsequent refocusing on the subject following the implementation of the change in the field of depth.