With the replacement of the former top model, the A620, the Canon PowerShot A640 has gone straight to the top. The camera has 
been given a small facelift and has a larger LCD screen in addition to the increase in pixels. Fortunately, Canon has kept the tilting construction of the LCD screen. This part is and will remain to be a definite advantage. The Canon A640 has also been given the necessary updates such as support for the new SD platform, the SDHC (Secure Digital High Capacity) flash memory card. For the rest, this beautiful, black camera bears a close resemblance to its predecessor. Why change a winning combination?
The Canon PowerShot A640 has a 4x optical zoom lens which realises a focal distance of 35-140 mm (equivalent to a 35 mm). Despite the comparatively large zoom range, the Canon PowerShot A640 has been kept reasonably compact. The lens has 8 elements in 7 groups, including two aspherical elements to maximise sharpness over the entire picture. The camera doesn’t have an optical image stabiliser and has to rely on high ISO settings to achieve a short shutter speed in order to avoid movement blur. Of course, this model also has a fast image processor; de DIGIC II.
Canon PowerShot A640 Digital Camera Review