(week 4)
An interesting class today. Even with my previous amount of experience and exposure to all this kind of thing, i was pleased with how much i learnt from Brian's class today.
He even helped me to finally understand what the popular film "The Matrix" is all about - something i have always stubbled with till now, so cheers Brian!
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| a binary matrix made up of bits and pieces ;) |
Computer Basics
It's all to do with "BITS" or otherwise known as Binary Digit.
Bit - the smallest unit of binary number having a value of 0 or 1. This is represented in a computer by an electrical current being on or off - or the direction of a magnetic polarity. Another way i like to think about it is like an electrical circuit, it is either an open (on) or closed (off) circuit. It can also be represented optically on media such as CD's and DVD's.
Considering a bit is either on or off, this equates to a bit having a value of 2:1. From a BIT comes a BYTE.
Byte - is a group of 8 bits - this can represent 256 values. Remember 1 bit has a value of 2 so if you multiply 2x2x2x2x2x2x2x2 you end up with 256. The following image explains this in a visual way.
A byte is then measured in a similar way to most other things. The following is an example of this:
Kilobyte - 1,024 bytes (rounded down to 1000 for the general public)
Megabyte - 1,048,576 bytes (again rounded off to 1,000,000)
Gigabyte - 1,073,741,824 bytes (or 1,000,000,000)
Terabyte & Petabyte - even bigger again !
So in other words this equates to the storage devices we use to store our digital computer files. Simple when you break it down in this way i think. Not to get this confused with RAM.
So.. how does that all translate visually?
Well images we see on screen are made up of PIXELS and displayed by an RGB (Red, Green & Blue) light source.
Pixels share a similarity to that of the printing industry. If you look closely at a printed photograph with a magnifying glass you will notice it is made up of lots and lots of coloured dots of CMYK (Cyan, Magenta, Yellow & Black) in a number of positions or patterns to create the impact of what we see as a recognisable image. So, pixels do much the same thing only in a different medium - they are screen-based. If you hold a magnifying glass up to your computer screen you can clearly see the RGB configuration.
Digital cameras sensors record the light passing through the lens in RGB.
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| the basic principals of how a digital camera records light |
One of the big selling points of a digital camera is how many megapixels it is. A megapixel is 1000 pixels. To explain this in relation to image size an example would be that an "18 megapixel digital camera" has an image size of 18,000 pixels. Broken down in a two dimensional sense that equates to 6000 pixels (wide) x 3000 pixels (high). A simple multiplication of the two figures will give you the amount of overall pixels the digital sensor is able to handle. The exact figure is likely to be a little more than 18,000,000 pixels, but the camera manufacturers will round it off to a nice round figure to make it less confusing for the general public.
However, don't be confused, because the amount of megapixels a digital camera has is different to the actual file size it can produce. Remember that the digital sensor records three colours of light (RGB) as seen in the above diagram. So this means each colour channel will record the 18,000 pixels and total them together and considering a pixel is basically a byte this means that in a RAW digital negative file the total will equate to 54,000 - so a 54MB file. That's big, hence why a photographer needs a quality computer to handle and process images of this size with easy and reliabilty.
Something i must now start to do as a professional photographer is think in Pixels per Inch (ppi) instead of Millimetres or Centimetres when referring to image size because those i will no doubt work with in the printing industry speak in inches (dpi - dots per inch) and (lpi - lines per inch) - so it's all relevant when you think about it.
D.
