Sensor CCD

In a digital camera it's the sensor CCD who collects the information concerning the image (those this are passed on by the light passing in transit by the objective).

It's this sensor (which is big as the nail of the little finger) which takes care to transform these light signals into digital signals.

A sensor is constituted by sensitive cells called photodiodes which contain themselves pixels (thus not to confuse photodiodes and pixels, as we shall it afterward).

The more there's of photodiodes and the more you're entitled to wait for photos of better quality. But it is not the main argument : the quality of the objective is also essential.

Photodiodes are quite various (indeed, if they were the quite same, they'd react to the light in a positive or negative way, of or a state 1 or 0, that is black or white).

There're thus photodiodes with red, green and blue filters, each of these colours being digitalised on 256 levels of luminosity or luminance:
What thus wants to say 256 levels of green, 256 of the red and 256 of the blue, all these combinations of colours put together give us:
256 x 256 x 256 = 16.7 million possible colours.

The surface of a sensor contains generally more photodiodes green than blue and red, this's in fact to adapt itself the most possible for the human eye which is more sensitive to the green than to two other colours.
A sensor can restore up to 16.7 million colours, but do you know that the human eye discerns it only on 2500, the compression of the images is based on this peculiarity.

Internal Software and A/N processor.

The CCD cannot regrettably treat alone the quantity of information relative to the image to him alone, one thus has appeal to a software of treatment (don't confuse with the software of retouch) to calculate the data to constitute a digital picture.
This software is internal in the device.

It's thus the work of the CCD and the software of treatment that "make" a digital picture.
This peculiarity is one of the inconveniences of the digital photo.
Who says said treatment time: indeed the handled data are put in a memory "plug" which stores what is already made by waiting to receive the continuation, the more the memory "plug" of the device is important and the more the treatment is accelerated.

But there's another important factor, the speed of the internal software which is variable according to the builder.
This fact makes that the digital device works very slow as regards the mode photo in squall.
According to the resolution and the device, one can have times of treatment going 5 seconds.
Builders try to minimize this trouble by increasing the buffer.

Storage
The image so reconstituted is sent to the internal memory in the device (on certain devices entry of range), on a card memory (so called flash memory), on floppy disk or even on mini hard disk.
Sony suggests, as for him, storing photos directly in a CD-Rom