Digital Cameras A Computer with a Lens
Photographic Goals: Cost Comparisons
Instead of buying film: Take pictures. Transfer to Computer. Reuse same storage device. Immediate results. Easy use of image-editing software. Many options for display and storage. Initial investment. Time in learning how to use equipment & software. Financial investment. The better the quality desired the more money required for camera, printer, other equipment. Advantages & Disadvantages
24 exposure roll of color film = $5.00 Development & Printing 4”x6” Prints = $5.52 ($0.23 ea.) Average price per print including film, developing & printing = $0.44 each. Scanning Service Photo CD = $2.82 Digital Images presented on Memory Device: 4”x6” Prints = $0.22 each (50 or more = $0.19 each) 24 Prints = $5.28 Photo CD = $2.82 One Hour Processing Time: Traditional with Scanning. Digital Images Printed. Cameras: Traditionalverse Digital Commercial Processing Costs
Filmless Cameras: • Operate essentially in the same way as conventional cameras. • The lens contains a variable-aperture diaphragm. • The camera has a shutter. • Many have an optical viewfinder. • Some digital camera models are built around existing camera bodies and lens systems.
The Core of a Digital Camera:The Imaging Device: CCD(Charge-Coupled Device) The sensor sits where the film ordinarily would. • The sensor’s surface is packed tight with microscopic light-gathering cells known as Pixels (picture elements). • Similar to silver-halide crystals in a film emulsion-larger pixels increase camera’s speed-decrease resolution. • In general, the more pixels a digital camera has, the more expensive it is.
The technical quality of a digital image is determined by the number of pixels & the amount of information each pixel holds. • The greater the number of pixels: (pixels per inch or ppi) • The greater the amount of detail that is recorded. • The more information per pixel: (bit depth or # of bits per pixel) • The smoother the gradation from one pixel to another. • Other factors also affect quality: • Enlargement • Quality of printer (dots per inch or dpi)
Resolution and File Size:Digital cameras are often described by their resolution. (the number of pixels they can use for an image) The examples above use 200 ppi, which provides a large enough file for adequate reproduction with most desktop inkjet printers. 300 ppi provides even better quality. In the first row, for example: 8” x 200ppi = 1600 pixels, 10” x 200ppi = 2000 pixels. Pixel by Pixel dimension = 1600 x 2000. Now multiply 1600 times 2000. 3.2 million pixels is another way of describing resolution. Each Pixel consists of 3 color values--red,green,blue—multiply the number of megapixels by 3. A 3.2 megapixel camera will yield a file size of approx. 9.6 megabytes for a good quality 8”x10” image
Picture Storage: Most digital cameras store their images on removable memory cards. • “Film” for a digital camera. • Several competing types. • Different camera brands use different types. • Capacities range from 128MB to 4GB. • Not all cameras have removable cards. • When a card is filled, you need to transfer its contents to your computer
Choosing the quality you need: • Too much of a good thing! • The bigger the file, the more space it occupies on the memory card. • Tradeoffs-quality versus amount of memory. • Achieving smaller digital files. • Use fewer pixels to take a picture. • Compress image files. • Combination of each. • Digital cameras let you choose. • High Quality – uses the most pixels and/or compresses the least. • How good is good enough?
Picture Format:Refers to a software scheme that saves the information needed to create the image. • How do you squeeze a large picture file into a smaller space? • Eliminate redundant information - Compression. • “Lossless” – A TIFF format is an example. • “Lossy” – A JPEG format is an example. (Saving an image repeatedly in JPEG format will eventually degrade its quality). • You can downsize a high-quality file for the Web, but you can’t make a large, beautiful print by expanding a low-quality file. • After transferring an image to the computer – always make a copy and work with that. Thus, preserving the original at its highest quality.
Original: 960 pixels x 1280 pixels @ 96 ppi = 3.52 M 10 inches x 13.3 inches Original: 480 pixels x 640 pixels @ 72 ppi = 900 K 6.7 inches x 8.9 inches
The Lens:All photographic lenses do the same basic job. • A CCD sensor is much smaller than a frame of 35mm film. • The most important way lenses differ is in their focal length. • Focal length controls: • Magnification • Angle of view • Depth of field 50mm lens on 35mm film-based camera 50mm lens on equivalent-size digital camera
Zoom Lenses:Combine a range of focal lengths into one lens. • Optical Zoom:Magnifies the image by the use of glass elements inside the lens. • Digital Zoom:Magnifies the image through the use of electronics by enlarging the pixels in the image. • As usual – Quality is the issue.
Kodak DC240 – Lens Specifications:Optical quality glassMaximum Aperture [wide:F/2.8, telephoto:F/4.5] Zoom [6X:3X optical, 2X digital]Focal Length [39 to 117mm (equivalent to 35mm camera), 6 to 18mm (actual)Focus Distance [wide/telephoto: 1.6ft. to infinity, close-up:0.82ft. to 1.6ft.] 35mm Disposable Camera With optical quality plastic lens Approx. 35mm focal length. 6mm Focal Length (39mm equivalent focal length on 35mm camera) 18mm Focal Length (117mm equivalent focal length on 35mm camera)
Sony FD Mavica – Lens Specifications: 10X optical zoom lensf = 6.0 – 60.0mm (39 – 390mm when converted into a 35mm still camera)F = 2.8 35mm Disposable Camera With optical quality plastic lens Approx. 35mm focal length. 6mm Focal Length (39mm equivalent focal length on 35mm camera) 60mm Focal Length (390mm equivalent focal length on 35mm camera)
Sony FD Mavica – Lens Specifications: 10X zoom lensf = 60.0mm (39 – 390mm when converted into a 35mm still camera)The maximum zoom magnification is 20X (2X digital zoom) 35mm Disposable Camera With optical quality plastic lens Approx. 35mm focal length. 60mm Focal Length (390mm equivalent focal length on 35mm camera) Digital Zoom
Macro Feature: Lets you get an enlarged image by focusing very close to a subject. • Often achieved optically. • Best choice for sharp close-ups.
Monitors & Viewfinders:Seeing what you’ve got. Optical Viewfinder • Optical viewfinders – similar to conventional cameras. • Liquid Crystal Display (LCD) monitors. • Great for close-ups. • Hard to see in bright light or at certain angles. • Lets you see your pictures almost as soon as you take it. LCD Monitor Optical Viewfinder LCD Monitor TIP: An LCD monitor drains power, so use it when you need it, but your batteries will last longer if you turn it off when you don’t need it.
White Balance: • Images are susceptible to lighting conditions. • Normally, the camera will adjust automatically. • If the image appears in strange colors – change the white balance mode.
Choosing a Digital Camera:Many types of digital cameras are available, from completely automatic to full-function professional models. • Ideally-Look for a Camera with: • LCD monitor plus an optical viewfinder. • A lens capable of optical zooming. • A flash that you can turn off. • Image Quality- • Greater the resolution, the better the quality at a given size and the more it costs. • Reaction Time- • Length of delay between the time you press the shutter and the moment the camera takes the picture, followed by the delay while the image downloads.
Choosing a Digital Camera:Spend time thinking about your needs before buying one. • Type of Memory- • Having a large amount of memory available means more high-quality pictures before having to download. • USB and Firewire connections are desirable. • Batteries- • Rechargeable nickel-metal hydride (NiMH) or lithium batteries offer extra life and viewing time. • Creative Control- • Consider the standard features you want on a traditional camera – control over f-stops, shutter speeds, focus, etc.
Use a Digital Camera: • Get Started Today • Every digital camera is different • Read your manual carefully • Make sure your camera has fresh batteries • Rechargeable batteries offer extra life • AC adapters useful indoors • Have Fun! • Spend some quality time with your camera and imaging editing software.
Many manufacturer’s post manuals on-line. A printed copy of the manual for the Nikon D50 Digital Camera is provided each time the camera is checked out.
Digital Cameras: Your Path to Filmless Photography
Unlimited Resources: • http://www.prenhall.com/london • http://www.kodak.com/eknec/PageQuerier.jhtml?pq-path=2/3/9/19&pq-locale=en_US • http://www.nikonusa.com/usa_home/home.jsp • http://www.nikonusa.com/template.php?cat=1&grp=2 • http://support.nikontech.com/cgi-bin/nikonusa.cfg/php/enduser/std_adp.php?p_faqid=13644 • http://www.fixya.com/ProductSearch.aspx?_s=Camera+Manual • http://www.powershot.com/powershot2/home.html • http://www.sonystyle.com/is-bin/INTERSHOP.enfinity/eCS/Store/en/-/USD/SY_BrowseCatalog- Images and Excerpts were taken from the following texts for use in this presentation: Horenstein, Henry and Russell Hart, Photography. Upper Saddle River, NJ: Prentice Hall, 2001 London, Barbara and J. Upton, K. Kobre & B. Brill, Photography. 7th ed. Upper Saddle River, NJ: Prentice Hall, 2002
A Flash Can Be Useful: No Fill Flash Fill Flash Used