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Well, digital image capture is getting better, the resolution of the high street 6Mpx camera is as good as 35 mm 100 ISO film and much better than the usual high street 400 ISO film. However digital cannot touch a 4x5 inch camera as far as image quality as most medium format films are far better than digital. Digital is popular because of its convenience and the low cost of its disposable frames.
I use digital because of its convenience and low cost.
As far as sound is concerned, the fundamental problem is quantum noise. This is due to the finite number of amplitude levels that may be captured. The same is true of digital image capture. The gray scale digitization process makes 256 levels represented by an 8 bit binary number and is only sampled where the pixel element sits. Similarly sound is captured by a series of samples taken at twice the highest frequency of the sound and then this amplitude is quantised into a large number of discrete amplitude steps and each is represented by a binary number (I think they use 16 bits to represent sound levels). Amplitudes in between the samples are not represented and levels outside one of the quantised steps is taken to be at the nearest step.
This sampling process gives rise to noise. Grain and finite quntisation in image capture is a well known failing and in sound the sampling frequency limits the upper frequency that can be captured, the quantisation noise is heard as a hiss.
However the cheaper and greater reliability and ease of use of digital outweighs these fundamental problems. Future refinement in terms of sampling frequency and an increase in the number of quantum levels will reduce these problems to a level that that human sense organs cannot detect.
One major advantage of digital is the recovery of a sound or image trace distorted by media aging or by transmission. This is made possible by the digital nature of the storage. If a number can be read, even though it may be damaged, then it can be accurately transmitted. The use of a “gray code” and multiple repeats single samples helps this process. CD sound recordings can have the same sample repeated three times and if there is one disagreement it is eliminated. Some schemes can recover the sound by carrying on with a prior sequence if there is a hole in the disk. However if digital sound goes wrong, like in the addressing of the sample, then it really does go wrong, it is not just distortion it is just random garble.
However, the future is digital.
Chris. Get more from the Web. FREE MSN Explorer download : http://explorer.msn.com |
