Introduction to Digital Photography Spring 2010 Instructor, Francesca Hampton
Topics well cover today Pros and Cons What digital means Examples of digital possibilities Pixels and resolution Memory chips Memory cards Some currently popular digital cameras Batteries and common accessories Other ways of going digital Introduction to our course web page
A caveat Like many amateur photographers, I am self-taught. We may occasionally have questions we will have to find answers for together, but finding where to look for answers is a key part of learning the basics. If you are curious to see my work, you can visit my online galleries at Photography by Francesca HamptonPhotography by Francesca Hampton (Picasa gallery) Or Cruzio gallery (older work)Cruzio gallery
Pros and Cons of going digital Pros See the shot now No more film costs! Easier to share & store Web & email ready Simple to retouch Creativity unlimited Easy to make your own cards, flyers and calendars. Cons Initial expense Computer and printer (usually) required Some technical knowledge needed
What makes a digital camera different? A digital camera captures light information onto a computer chip which converts it to a mathematical formula. The chip may be a Coupled Device (CCD) or Complementary Metal Oxide Semiconductor (CMOS). In regular cameras light would go directly onto film. In digital cameras the processed light information is written onto Memory cards which can be erased and reused once the images have been uploaded to a computer, e.g. you can take unlimited pictures for free! No more film!
Light hitting a CMOS chip is similar Light is measured by each small square in the sensor and processed into a mathematical pattern of ones and zeros that allow for the expression of millions of colors.
CCD or CMOS Chip Size CMOS is less expensive to produce but not as sensitive as a CCD Larger chips create image files with more information measured in dots per inch or dpi. Up to a point, this means you can produce physically larger images without pixalization artifacts CMOS
What the heck is a pixalization artifact? When digital information is recorded inaccurately, some pixels develop errors and show the wrong color. This can result in a grainy or rainbow effect most visible in clear areas such as the sky. Anti-Noise software can reduce this effect. The best antidote is to take a picture at a resolution large enough for the print size you want and find the most accurate light setting before shooting.
Lets start with another question. What is a digital image? A digital image is created by thousands of tiny squares of digital information, called picture elements or pixels. An image size is described as dots (pixels) wide by dots high. Typical sizes are 1280 x 960, or 2560 x 1920. Even 5184 x 3456 is common this year. Each pixel is a single color expressed as a digital pattern of 8,16, 24 or 32 ones and zeroes.
Digital Image Characteristics Even 24-bit color allows for 16 million + shades. From a distance, pixels blend to look like a picture. Up close each pixel becomes visible. More total pixels allow more detail in an image. However, more pixels also mean more computer memory space to store the image..
Image enlarged a lot! Notice that each pixel square expresses a single color.
Digital images are recorded on memory cards There are several types of memory cards. Your camera will use only one type. Find out what it is. Memory cards can be removed and inserted into card readers to upload them into computers or directly to printers. Your camera itself can serve as a card reader. Memory cards are erasable and reusable and hold literally thousands of images -up to 16GB!
Image Size versus print size A 1 Megapixel camera in a cell phone can give good results online viewing since computer screen resolution is only 72dpi, dots per inch - but it is not much good for prints beyond 3X5 inches. A 6 Megapixel camera can produce a good 13 x 19 print or even larger depending on the subject. These days, even inexpensive cameras routinely offer 10 or more MB and prints of 40X60 or more. Be aware that there is a trade off in the amount of noise in high MB cameras. The best image result may actually come from a medium high MB camera with a high quality lens and processor.
So many choices! We will look more closely at digital camera features next class but here is a sampling of some currently popular models online today. Canon Digital Rebel XS $579 Nikon D90 $750 $950 w/lense kit Kodak easyshare $79 Panasonic Lumix $140
All the other stuff Common digital accessories Hmm - more stuff to buy! Batteries/ re-charger Strobe lights? Lens cleaner? Camera bag? Cables (come with camera) Tripod? Card reader? But remember the trade off - no film & very low print costs!
Still prefer film but want the advantages of digitalization? 1. Go right ahead, keep using your film camera but order a CD (compact disk) when you have the film developed. Although this will cost a little extra, the digital file on a CD is just as usable as the one from a digital camera if it is scanned at high resolution. 2. For old prints or 35 mm slides, buy a print scanner or a film (slide) scanner and scan your own photos into digital format on your own computer - or, again, to to a professional service. (Bay Photo offers this locally).print scanner film (slide) scanner
Ready to start the adventure? Lets see what cameras we have in the class today and turn them on!
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