On: Mon, 17 Nov 2003 Matt wrote:- > Regarding Dig and ASA, I was always told that a chip has a fixed > sensitivity of around 12.5 ASA and the rest was done by amplifying the > signal off the chip. Its a bit like turning up the volume on yer HI-Fi but > you can only give it so much Gain before distortion sets in i.e. Noise etc . > This is why top end dig back makers tend to avoid it as a feature.
The definition of an electrical amplifier is "a piece of wire with gain" and an analogy with hi-fi is a close one. Analog hi-fi to be precise. Chips record fluctuating light levels as electrical signals along with random analog signal noise. A high signal to noise ratio means an optically clean image without artifacts. Actually, chips will record beyond 10-12 stops, only they are clipped to make something useable as a signal. Colour is not actually colour as with film, but a heavily treated electrical signal that conforms to a mathematical model of colour, commonly called a colourspace. I am amused at the recent proliferation of RAW-file 'treatments' software to process what are simply data-dumps off a chip. Seems that different manufacturers have different ideas as to what constitutes good colour with on-board software. Firmware updates are an admission of failure. Yes, a raw-feed straight off the chip would be very useful (as a standard high-end feature in 2005 please) I mean, when you buy a decent electric guitar, the first thing everybody does is to replace the pickups and strings. Make sure it goes up to eleven. Anyway, mass produced water-cooled chips are going to be with us very soon. Pause for thought......how many of us 'high-end' digital practioners have ever seen true fidelity colour in either capture and/or in reproduction? I say this as a lot of what is said about high-end capture is wishful hearsay. In fact, with a bit of lateral thinking about post-signal processing it is possible for anyone on a low-to-no budget to achieve really excellent fidelity of colour and tonality with lo-fi digital capture. I kid you not. William Curwen =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
