In an automatic focus adjustment apparatus, a setting unit sets, on an image sensor, a first range in which defocus information is detected using a phase difference detection and a second range in which a focus state is detected using a contrast detection. The second range is set so as to include the first range. In a case where the second range is detected by the contrast detection as being in an in-focus state, a control unit changes a control mode into a predetermined control mode in which the driving of the focus lens is limited according to the defocus information in the first range detected by the phase difference detection.

In an automatic focus adjustment apparatus, a setting unit sets, on an image sensor, a first range in which defocus information is detected using a phase difference detection and a second range in which a focus state is detected using a contrast detection. The second range is set so as to include the first range. In a case where the second range is detected by the contrast detection as being in an in-focus state, a control unit changes a control mode into a predetermined control mode in which the driving of the focus lens is limited according to the defocus information in the first range detected by the phase difference detection.

A cell observation apparatus includes an imaging device capable of imaging a vessel containing cells while varying a focal position, an illuminating device for irradiating the vessel with illuminating light; and a controller for controlling the imaging device. The controller includes: a z-stack imaging controller for causing the imaging device to take a plurality of z-stack images while varying the focal position; a variance value calculation part for calculating a variance value of pixels values for each of the z-stack images; an edge index value calculation part for calculating an edge index value indicative of edge strength for each of the z-stack images; a focus evaluation value calculation part for calculating a focus evaluation value having a minimum value in an in-focus position, based on the variance value and the edge index value; and an in-focus position estimation part for calculating the focal position where the focus evaluation value has a minimum value to estimate the in-focus position. This achieves the estimation of the in-focus position with high precision while suppressing the increase in the number of images taken for z-stack imaging.

An error is reduced in phase difference detection of an imaging element including a phase difference pixel with an on-chip lens in common for a pair of pixels. The imaging element includes a pixel, an individual on-chip lens, a plurality of phase difference pixels, a common on-chip lens, and a pixel circuit. The individual on-chip lens individually collects incident light for each pixel. The phase difference pixels are arranged adjacent to each other to detect a phase difference. The common on-chip lens is arranged in common for the plurality of phase difference pixels and collects incident light in common. The pixel circuit is formed in a semiconductor substrate and generates an image signal on the basis of a transferred charge. Charge transfer units of the plurality of phase difference pixels are in a region between the common on-chip lens and the individual on-chip lens.

A focus detection unit to adjust a focal point of an image, of an object, formed by an optical system includes a first output section, a second output section, and a projection optical system. The first output section includes a first light modulation element configured to generate a first pattern image based on incident light and is configured to output the generated first pattern image. The second output section includes a second light modulation element configured to generate a second pattern image based on incident light and is configured to output the generated second pattern image. The projection optical system is configured to project the output first pattern image and the output second pattern image such that the output first pattern image and the output second pattern image have a predetermined positional relationship at an in-focus position of the optical system.

A focus detection unit to adjust a focal point of an image, of an object, formed by an optical system includes a first output section, a second output section, and a projection optical system. The first output section includes a first light modulation element configured to generate a first pattern image based on incident light and is configured to output the generated first pattern image. The second output section includes a second light modulation element configured to generate a second pattern image based on incident light and is configured to output the generated second pattern image. The projection optical system is configured to project the output first pattern image and the output second pattern image such that the output first pattern image and the output second pattern image have a predetermined positional relationship at an in-focus position of the optical system.

An image pickup apparatus is equipped with a distance information calculator, a high frequency signal extractor, a focus assist signal generator, and a signal synthesizer. The distance information calculator calculates distance information of a video signal and generates an in-focus range signal from current focus information and the distance information. The high frequency signal extractor extracts a high frequency signal of the video signal. The focus assist signal generator generates a focus assist signal representing a focused region by using the high frequency signal and the in-focus range signal. The signal synthesizer synthesizes the focus assist signal with the video signal to generate a focus-assist-signal-added video signal.

An image pickup apparatus is equipped with a distance information calculator, a high frequency signal extractor, a focus assist signal generator, and a signal synthesizer. The distance information calculator calculates distance information of a video signal and generates an in-focus range signal from current focus information and the distance information. The high frequency signal extractor extracts a high frequency signal of the video signal. The focus assist signal generator generates a focus assist signal representing a focused region by using the high frequency signal and the in-focus range signal. The signal synthesizer synthesizes the focus assist signal with the video signal to generate a focus-assist-signal-added video signal.

A camera auto-focus apparatus includes a lens scan control circuit, a lens position compensation circuit, and a lens position decision circuit. During an auto-focus procedure, the lens scan control circuit controls movement of a lens according to a plurality of lens positions, and obtains a plurality of focus values corresponding to the lens positions respectively. The lens position compensation circuit determines a position compensation value according to the movement of the lens. The lens position decision circuit determines a focused lens position according to the position compensation value, the lens positions and the focus values.

A camera auto-focus apparatus includes a lens scan control circuit, a lens position compensation circuit, and a lens position decision circuit. During an auto-focus procedure, the lens scan control circuit controls movement of a lens according to a plurality of lens positions, and obtains a plurality of focus values corresponding to the lens positions respectively. The lens position compensation circuit determines a position compensation value according to the movement of the lens. The lens position decision circuit determines a focused lens position according to the position compensation value, the lens positions and the focus values.