Optical apparatus

An optical apparatus comprising:

• a signal generator which extracts signals in a plurality of frequency bands from an output from an image-pickup part and generates focus signals from the extracted signals;
• and
• a controller which performs auto-focus control such that each of the focus signals approaches the highest value,
• wherein the controller uses a first focus signal and a second focus signal in the auto-focus control, and
• wherein the second focus signal is a synthesis signal formed by synthesizing at least two of a focus signal in a first frequency band and a focus signal in a second frequency band lower than the first frequency band, and the first focus signal is a synthesis signal formed by synthesizing focus signals in plural frequency bands,
• wherein a ratio of the focus signal in the first frequency band synthesized in the second focus signal to the entire second focus signal is higher than that a ratio of the focus signal in the first frequency band in the first focus signal to the entire first focus signal,
• wherein the controller performs, when a resolution of an image signal obtained by the image-pickup part is a first resolution, the auto-focus control with the first focus signal, and
• wherein the controller performs, when the resolution of the image signal is a second resolution higher than the first resolution, the auto-focus control with the first focus signal and then performs the auto-focus control with the second focus signal.