Resolution


Right Image
Canon EOS D30, Tokina 300mm
f-4 ATX, 1.4X teleconverter (equivalent to about 670mm f-5.6 in 35mm), 1/60 sec at f-5.6, ISO set to 200, aperture priority, partial metering, +1 stop exposure compensation, autofocus. Bogen tripod and ball head.

Resolution seems to be very confusing to a lot of people
who want to get into digital photography. It is really very simple. Resolution is the number of dots or pixels that make up a final image. Digital camera have sensors that record images the way film does in traditional cameras. Sensors are composed of thousands or millions of pixels. More pixels means better resolution and detail. One million pixels is one megapixel. A digital camera with three-megapixel produces images made of about three million individual dots or pixels. By the way, in case you were wondering,  pixel stands for picture elements. "Pix" is short for pictures and "el" for elements. A 3 megapixel digital camera obviously produces more detailed images than a 2 megapixel camera. You will see that resolution is also described by numbers like 2496 x 1662, the maximum resolution  of Canon EOS-1D for example. EOS-1D has a 4.4 megapixel resolution. 2496 x 1662 = 4148352 or approximately 4.4 megapixel. The first number is the number of pixels horizontally and the second number is the pixels vertically on the CCD. Scanner resolution is very similar. Scanner's optical resolution is the number of pixels a scanner can see. A 2400 dpi film scanner can see 2400 dots per inch (dpi). Scanning at higher resolution allows you to make larger prints while maintaining detail.

You don't need high resolution for each and every shot you take or scan. It all depends on what you intend to do with your pictures. If you want to make prints, lets say 4 x 6 using a Canon EOS-1D which has a maximum resolution of 2496 x 1662 , you'll need 1800 x 1200 or about 2.2 megapixel resolution. Divide 1800 by 300 and 1200 by 300 and result is 6 x 4. The reason for dividing these numbers by 300 is because of printer's resolution which is generally 300 dpi which gives quality results. To make an 8 x 10 print you'll need 3000 x 2400 or 7.2 megapixel resolution. So, if you don't need to make larger prints, it makes no sense to pay more for resolution. For e-mailing your pictures or viewing on your computer screen, 75 dpi is enough. Any point-and-shoot digital camera or scanner is capable of this. You can always use your image editing software to make larger prints with smaller files. A quality image saved as Tiff, Raw, or high quality JPEG can be enlarged for making larger prints. This however, will lower the quality of the final print to some degree.

When choosing a digital camera or scanner, check the maximum resolution to see if it gives you enough information to work with. Don't waste your money on more resolution if you won't need it. It is best to see what other features the camera or scanner has besides resolution. Look for the maximum resolution you need and then all the absolute necessary features before purchasing your digital camera or scanner. I'd rather have a 3 megapixel digital camera with all the features I like in my 35mm camera than a 5 megapixel model that won't let me take 100 percent control over each and every shot I take.