A digital camera includes a shutter button. An optimal compression ratio of an image signal fetched in response to a photographing instruction from the shutter button is predicted prior to the photographing instruction. More specifically, an image signal fetched before application of the photographing instruction is compressed by a JPEG codec, and the optimal compression ratio is predicted based on a size of a compressed image signal thus obtained. An image signal fetched in response to the photographing instruction is compressed on the basis of the optimal compression ratio, and a compressed image signal thus obtained is recorded onto a recording medium.
1. A digital camera that periodically creates, until a recording Instruction is issued, a first still image corresponding to an object scene in such a manner as a real time display is omitted, and creates, when the recording instruction is issued, a second still image corresponding to the object scene so as to record the second still image into a recording medium in a compressed state, comprising:
a calculator for calculating a specific compression ratio coefficient capable of compressing the first still image to a specific size;
a compressor for compressing the second still image by use of the specific compression ratio coefficient;
a corrector for correcting the specific compression ratio coefficient when a compressed second still image created by said compressor fails to satisfy a size condition including the specific size; and
a recorder for recording the compressed second still image satisfying the size condition into said recording medium, wherein the first still image and the second still image have the same resolution with each other.
2. A digital camera according to claim 1 , wherein said calculator includes a first still image compressor for compressing the first still image, and a calculation executor for calculating the specific compression ratio coefficient on the basis of a compressed first still image created by said first still image compressor.
3. A digital camera according to claim 1 , wherein said recorder records a newest compressed second still image into said recording medium when the number of compressing operations directed to the second still image reaches a threshold value.
4. A digital camera according to claim 1 , further comprising a shutter button to issue the recording instruction.