1. Field of the Invention
The present invention relates to a camera system, a digital camera, and a method for controlling a digital camera and, more particularly, to a camera system that makes backup data of image data obtained by photographing by a digital camera, a digital camera which can transfer image data obtained by photographing to the outside, and a method for controlling a digital camera.
2. Description of the Related Art
In recent years, digital cameras such as digital still cameras or digital video cameras have become popular. Such cameras pick the image of an object by using a solid-state image pickup element such as a CCD (Charge Coupled Device) that records digital image data indicating the object image obtained by the image pickup on a mobile recording medium such as a smart medium or a compact flash.
In these kinds of digital cameras, as a method for protecting image data recorded on the recording media, the following two methods are employed.                1. Pieces of image data to be protected are selected by a user one by one to give a read-only attribute to each selected image data.        2. Read-only attributes are given to all pieces of recorded image data at once.        
Examples of the protect methods of the two types will be described below in detail. With reference to FIGS. 15A to 15D, a method for giving a read-only attribute to each selected piece of image data will be described below.
A user depresses a menu/execution switch (not shown) prepared for displaying a menu on an image monitor 40 constituted by a liquid crystal display or the like arranged on a digital camera. In accordance with this operation, a menu screen shown in FIG. 15A is displayed on the image monitor 40 of the digital camera.
The user selects a protect menu indicated by a key-shaped mark from the menu screen such that an operation switch (not shown) on which an arrow key indicating four moving directions, e.g., upper, lower, left, and right directions in a display area of the image monitor 40 is operated. In this manner, a protect menu shown in FIG. 15B is displayed on the image monitor 40 of the digital camera. Therefore, the user designates “1 frame set” of the protect menu by operating the operation switch. In accordance with this, on the image monitor 40 of the digital camera, an image indicated by image data recorded on a recording medium by photographing in advance is displayed as a thumbnail. For this reason, the user designates an image to be protected from the thumbnail by operating the operation switch. In accordance with the designation, a screen is displayed on the image monitor 40 of the digital camera. That screen urges the user to perform re-confirmation, as shown in FIG. 15C. When image data corresponding to a designated image is to be protected, the user depresses the menu/execution switch. When the image data are to be canceled, the user depresses a cancel/return switch (not shown).
When the user depresses the menu/execution switch, a read-only attribute is set with respect to image data corresponding to an image designated by the user in the digital camera to protect the image data, and a key-shaped mark is displayed at the upper right portion of the display area of the image monitor 40 as shown in FIG. 15D.
A method for giving read-only attributes to all pieces of recorded image data at once will be described below with reference to FIGS. 16A to 16C.
First, the user depresses the menu/execution switch. In accordance with this, a menu screen shown in FIG. 16A is displayed on the image monitor 40 of the digital camera.
The user selects a protect menu from the menu screen by operating the operation switch in the same manner as described above. In this manner, a protect menu shown in FIG. 16B is displayed on the image monitor 40 of the digital camera. In this state, the user designates “all frame set” of the protect menu by operating the operation switch. In accordance with this, a screen, which urges the user to perform re-confirmation shown in FIG. 16C, is displayed on the image monitor 40 of the digital camera. When all the pieces of recorded image data are protected at once, the user depresses the menu/execution switch. When the protection is canceled, the user depresses the cancel/return switch.
When the user depresses the menu/execution switch, in the digital camera, read-only attributes are set for all the pieces of recorded image data to protect the image data.
Even though a read-only attribute is given to the image data recorded on the recording medium to protect the image data by these methods, when the digital camera is connected to an external storage device such as a hard disk drive or an information terminal device such as a personal computer including a storage device to store the image data recorded on the recording medium of the digital camera in the external storage device or the storage device arranged in the information terminal device as backup data, the image data is expected to be erased from the recording medium in many cases.
However, in the conventional digital camera, it is very complicated to cancel a read-only attribute, which is set once, because the same troublesome procedure for setting protection described in FIGS. 15A to 15D and FIGS. 16A to 16C must be performed. Therefore, it is also complicated to erase image data, to which a read-only attribute is set, from a recording medium.