How did Sony developed the DSC-HX1, a 20x zoom camera with a built-in lens? We delved into the development process of the camera.
Why did it come so late?
Many engineers are interested to know why Sony fell way behind Casio Computer Co Ltd in commercialization of high-speed camera. Casio released the EX-F1, which incorporates the first-generation product (pixel pitch: 2.5μm) of Sony's ultra high-speed CMOS sensor, one year ago.
There are several reasons for the delay, but the largest factor is a decision made by Sony's digital camera division, which considered that "the specifications of the first-generation product are not sufficient to develop a good seller and Sony should wait the release of the second-generation product (pixel pitch: 1.7μm)."
The gross sensor resolution of the first-generation CMOS sensor is 6.6 Mpixels. In Japan, there are distributors that are good at explaining products to customers, such as Yodobashi Camera Ltd and Big Camera Co Ltd, so cameras equipped with the first-generation CMOS sensor may sell well.
However, in the US market, for example, where the majority of distributors use only a single label (ie, a small point-of-purchase display) for sales promotion, it is difficult to sell cameras that offer fewer pixels than the lowest priced cameras, yet are far more expensive.
In addition, Sony's product planning strategy contributed to the delay of the commercialization. Naturally, Sony wants to prop up the average unit price of compact cameras, which has been on the decline, by introducing a model equipped with an ultra high-speed CMOS sensor. And, as a matter of course, the company pinned its hope on a high zoom camera considering that consumers who want this function are likely to pay for the new functions provided by the ultra high-speed CMOS sensor.
However, high zoom cameras are currently competing for higher zoom levels. Cameras with less than 20x zoom might be regarded as "lacking" by distributors and customers. Then, what if 20x zoom was realized by using the first-generation product and without too much cost for the lens? The lens unit might be extended too long when the camera shoots a picture, though this has not been confirmed with Sony.
The parameter that most significantly influences the length of the lens unit is the size of the image sensor. The size of the first-generation product is as large as 1/1.8 inch (the diagonal line of the chip surface where pixels are embedded is 8.9mm). Meanwhile, that of the second-generation product is 1/2.33 inch (7.63mm diagonal line), which is equivalent to the CCDs in other manufacturers' high zoom cameras.
Furthermore, Sony's digital camera division thought that the first-generation product has some problems in terms of image quality. It has a pixel pitch as large as 2.5μm, but the noise is not substantially low compared with smaller pitched CCDs used in other manufacturers' high zoom cameras. Therefore, "a very clear image," a selling point that can be easily understood by consumers, was not attained.
The noise level of the second-generation product (pixel pitch: 1.7μm) is lower than that of CCDs with the same pitch, according to Sony. CCDs incorporated in other manufacturers' high zoom cameras have a pixel pitch of about 1.5μm.
In the final part of the story, technological information, including the composition of the image processing LSI, will be reported in the form of a Q&A session.