How is an image recorded with Digital Photography?
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3 Responses to “How is an image recorded with Digital Photography?”
I’ll assume you know how an ordinary film camera works.
In digital photography, the film is replace by an electronic image sensor. The surface of the sensor is divided up into millions of separate little light-sensitive areas. The signal from each area is converted into a number. The numbers (actually sets of three numbers, one each for red, green and blue) vary according to how bright or dark or what colour that tiny bit of image is. And all these millions of numbers are recorded on a memory card when you press the button.
So your digital picture is just a great long list of numbers that describe the exact colour of each little element of the picture. These little elements are called pixels (short for picture cells).
Your computer can read these numbers and use them to re-create the image on a screen or send it to a printer, which uses the numbers to work out how much of each ink to ****** on to the paper at each point.
In a way, it’s all a lot simpler than using film. And certainly much quicker!
The digital image is not recorded as a “picture”. Instead the digital image file consists of coding that allows computer image hardware (monitors and printers) to re-assemble and present the picture.
The details of the image file vary with the file type (JPEG, TIFF, BITMAP, etc.), but generally consist of:
. An overall description section that has dimensions, pic type, dates, camera settings, etc.
. A pixel by pixel listing describing the color of each pixel. Most cameras use 24 computer bits (8 each for Red, Blue & Green) for each pixel. (You can make any projected color from some combination of Red/Blue/Green.)
So that is 3 bytes per pixel times the number of camera megapixels, plus a few hundred bytes general overhead. For example a 5 MP camera generates 3 x 5 MP = about a 15 MB file before compression. Most digicams use the JPEG file type, which provides compression down to about 2.5 MB.
March 26th, 2009 at 6:05 pm
I’ll assume you know how an ordinary film camera works.
In digital photography, the film is replace by an electronic image sensor. The surface of the sensor is divided up into millions of separate little light-sensitive areas. The signal from each area is converted into a number. The numbers (actually sets of three numbers, one each for red, green and blue) vary according to how bright or dark or what colour that tiny bit of image is. And all these millions of numbers are recorded on a memory card when you press the button.
So your digital picture is just a great long list of numbers that describe the exact colour of each little element of the picture. These little elements are called pixels (short for picture cells).
Your computer can read these numbers and use them to re-create the image on a screen or send it to a printer, which uses the numbers to work out how much of each ink to ****** on to the paper at each point.
In a way, it’s all a lot simpler than using film. And certainly much quicker!
March 29th, 2009 at 9:13 pm
The digital image is not recorded as a “picture”. Instead the digital image file consists of coding that allows computer image hardware (monitors and printers) to re-assemble and present the picture.
The details of the image file vary with the file type (JPEG, TIFF, BITMAP, etc.), but generally consist of:
. An overall description section that has dimensions, pic type, dates, camera settings, etc.
. A pixel by pixel listing describing the color of each pixel. Most cameras use 24 computer bits (8 each for Red, Blue & Green) for each pixel. (You can make any projected color from some combination of Red/Blue/Green.)
So that is 3 bytes per pixel times the number of camera megapixels, plus a few hundred bytes general overhead. For example a 5 MP camera generates 3 x 5 MP = about a 15 MB file before compression. Most digicams use the JPEG file type, which provides compression down to about 2.5 MB.
Good Luck
March 30th, 2009 at 7:32 pm
I recommand you a Free Online Photography Course
it include ten lessons on Photography.
Lesson 1: Composition And Impact - It’s A Beautiful Photograph, But Do You Know WHY It’s Beautiful?
Lesson Two: Aperture And Shutter Speed - How They Work Together
Lesson 3: The lens - choosing camera optics.
Lesson 4: ISO, Grain, Transparency vs. Negative, Specialty Films
Lesson 5: Fun Effects - Camera Filters, Soft Focus, Zooming And Panning
Lesson 6: Landscape, Nature and Travel Photography
Lesson 7: Portraits And Studio Lighting
Lesson 8: Studio Lighting - Still Life and Product Photography
Lesson 9: Tying It All Together
Lesson 10: Special Requests
good luck !