We know that picture files are dots. We know that more dots means more detail and quality. But we also know that more dots means bigger and longer file sizes - a problem when e-mailing or viewing photos on the web....
So the MATH JOCKEYS got together and came up with the idea of COMPRESSION. They figured out how to mathematically *squish* the dots in a photo file so that it would have the same number of dots, but the file size would be smaller. Here's a simple way to explain how they did it:
Imagine a house photo with a big blue sky. In a normal picture file, this would be a whole bunch of blue dots - I mean *lots* of blue dots.... Think of the file looking like this: Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,Blue Dot,... and keep going for a couple-three thousand more. No wonder the file is so big!
Now, all files have to have a name. And in Windows, they also have an "ending" called an *extension*. You've seen this in file names such as: photo1.jpg, 123main.bmp, bkyard.tif, etc. The *extension* is the part of the file name that comes after the "." (period) - Typically 3 letters and/or numbers.
The *Extension* tells Windows and your programs just what kind of file it is. Is it a picture? a word processing document? a database? an e-mail? whatever? So the Nerds get together and all agree on these endings or extensions, so that we can make programs that know how to look at photos or other kinds of files.
In the Digicam world, here are the various file types you'll run into:
.bmp - Stands for Bitmap. This is a basic image file. "Bitmap" means it's a *map* of all the *bits* (which is programmer talk for "dots")
.tif - Another kind of Bitmap that is usually made by scanners.
.jpg - Pronounced "Jay-Peg" - this is the main kind of compressed file used on the internet. It is used best for photos.
.gif - Pronounced "Jiff". This is another kind of compressed file and is best for graphics, clipart, and "animated" graphics. Pictures can be made into .gif's, but they are best as .jpg's
.fpx - Kodak flashpix format. Since it is not used by everyone, avoid this for sending to others or using in other programs.
PhotoShop, Picture Port, and many other special programs use file types and extensions that are non-standard. Avoid using these unless you only plan on using the files for your own in-house use.
The file extension is important because it tells your software how to look at the file. If you take off the extension, the computer doesn't know what it is. If you change the ending, the computer will try to do the wrong thing with the file and it probably won/t work.
Most of your programs have the ability to change from one kind of file to another. When you use the menus, try [File][SaveAs] or [File][Export]. When you are asked for the new file name, there is usually a line that says "File Type" somewhere under the name. Use the drop-down box to choose .Jpg if you are saving a file to use on the Net.
Good news - nowadays, most of your cameras and software will make the .jpg for you!
E-mail me a "JPeg" file. And in getting ready to start more on the "Lab" section, lets start looking at some photos!
If you don't know what to shoot, here's a suggestion - send me a photo of the *BACK* of a house. We all see a zillion front shots, but not as many of "rears." The shot can be looking at the house or the view. It does not have to be a listing, just get a shot from your neighborhood or while you're out and about. But SHOOT it and SEND it. HINT - Don't shoot from straight-on, get some angle or different position to make the shoot look more interesting....
"Practice Makes Picture-Perfect!"
Some Study Links: