david e. pitts digital cameras 101 digital cameras by david e. pitts march 27, 2012 copyright 2012

David E. Pitts

Digital Cameras 101Digital Cameras 101

Digital Cameras

by David E. Pitts

March 27, 2012Copyright 2012

David E. Pitts


3 Types of Digital Cameras

Consumer - Point and shoot ($100 - $400)

Prosumer - Serious amateur photographers (≈ $800)

Professional - Large expensive cameras (≥ $1,000)

David E. Pitts


• Instead of film an array of silicon chips is used.

• Typical 5 megapixel sensor is a 5 x 7 mm silicon array of chips (35 mm cameras have an image area of 24 x 36 mm)

• Each number in the Array represents one Picture Element (Pixel).

One Pixel

David E. Pitts


http://en.wikipedia.org/wiki/Full_frame_digital_SLR

David E. Pitts


• Each pixel on the silicon array has a blue, red, or green filter over it.

• Interpolation is used to obtain all 3 colors for each pixel.

• Green is used more because it is near the peak of the solar spectrum.

David E. Pitts


http://cameras.about.com/gi/dynamic/offsite.htm

David E. Pitts


Digital Image

• Each pixel is saved as 3 colors (Red, Green, and Blue)

• The grey level range in each color pixel is usually 8 bits (256 grey levels). This gives 16 million hues of color; the range of the human eye.

David E. Pitts


Moire Patterns can be generated when photographing patterns with low cost digital cameras.

David E. Pitts


Advantages of digital cameras

• Convenience - No film needed. Your photos are free so take a lot of photos and toss the bad ones.

• Cost - You will save on film and developing. This will quickly pay for the cost of the camera.

Film cost per photo = 20 cents

Developing/printing cost per film photo = 20 cents

A $200 camera is paid for after 500 photos.

David E. Pitts


Advantages of digital cameras continued

• Flexibility - See your images on the LCD. Take the photo again if you want to. However, detailed quality cannot be assessed on the small LCD on the back of the camera.

• Color – The color gamut is greater for digital cameras than for film. This means that the colors are brighter and have a greater range.

David E. Pitts


• CIE Chromaticity Diagram showing the Gamut of a CRT

David E. Pitts


Disadvantages of digital cameras

• Quality - The best digital cameras match the resolution of film, but are expensive. (≥ $2,000)

• Shutter lag - Most inexpensive digital cameras take a few seconds to store each image. This makes them unsuitable for action photography (children).

• Back lighting is a serious problem– You must be careful to not compose a photo with a bright window next to the subject since the subject will be underexposed

• Don’t use digital zoom

David E. Pitts


http://cameras.about.com/gi/dynamic/offsite.htm

David E. Pitts


• Resolution - Generally, you'll pay more for higher resolution cameras.

• Capacity The size of the memory chip you purchased determines the number of photos you can store. 1 gigabyte chip will hold about 800 photos at 3.2 megapixel (Cost ≈ $25.00). Keep a couple of chips handy.

• Optics. Most consumer cameras (≥ $200) have zoom lenses that range from wide-angle to short telephoto. More expensive cameras have better optics.

• Most digital cameras come with a built-in automatic flash.

• Use jpg (jpeg) compression format unless you are a professional photographer.

David E. Pitts


• Film Cameras

• 35 mm film image is equal to 30 - 40 megabytes

• Image on the film is 24 x 36 mm

• Film is sensitive from 0.3 to 0.9 µm

• Digital Cameras are sensitive into near infrared 1.1 µm. However, these wavelengths are only used on special scientific cameras.

David E. Pitts


Professional Digital Cameras

• Most digital cameras have CCD sensors that are smaller than 35 mm slides (24 x 36 mm). This necessitates a conversion factor when calculating the f stop for a particular lens setting.

• Large raw files can result from the professional digital cameraswhich match 35 mm film resolution.

• Professional digital cameras often have 12 bit resolution for each color.

• Can shoot photos quickly like expensive film cameras.

David E. Pitts


DIGITAL CAMERAS•Foveon Inc. has created a new CMOS CCD which has 3 detectors for each pixel on a single chip.•Current single chip cameras require adjacent detectors for each color, thereby requiring interpolation.•Camera using the X3 chip is available now, 10 megapixels Sigma SD10, $1,350.00, http://www.sigma-photo.com/Html/Cameras_sd10.htm

David E. Pitts


Print capability versus camera resolution

• 3.2 megapixels produces quality 4 x 6 inch prints

• 8 megapixels produces quality 30 x 40 inch prints

David E. Pitts


Archiving your digital photos

Prints• http://www.shutterfly.com/

• http://photo.walgreens.com/howitworks

• Walmart, Sams Club, etc

• PictBridge capability allows direct connection to a printer without a computer

David E. Pitts


Archiving your digital photos continued

CD’s and DVD’s

• Optical Media Dye layer in plastic substrate (lifetime 2 to 5 years)

• CD SINGLE SIDED 700 megabytes

• DVD (Digital Video Disc) Single layer 4.7 Gigabytes, dual layer 9 Gigabytes

David E. Pitts


Archiving your digital photos

Film is the best media for preserving data more than 5 years.

First permanent photographic images

• 1834 Henry Fox Talbot • 1837: Louis Daguerre

• Photos which have been kept in a cool, dry, dark environment have survived from the time of the United States Civil War.

• Video tape only last 2 to 5 years.

• Sharing photos - http://www.flickr.com/photos/iright/

david e. pitts digital cameras 101 digital cameras by david e. pitts march 27, 2012 copyright 2012

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