For the past 6 columns I have discussed different features of the camera. We have covered the camera body, the lenses, and the flash systems. Let’s now focus on the image itself, primarily the type of file, its size, and how it’s stored.
When light enters a camera through its lens after it bounces off the subject it is recorded by the computer chip inside the camera. The chip is essentially an image processor that breaks the light into its red, green, and blue components and creates an image from this data. Let’s not get too complicated and leave it at that. I want this column to focus more on what’s an economical and efficient method to capture, store, transfer, and display your images as opposed to how they are created.
Let’s talk about file “type” first. Practically every type of digital cameras saves the image to a “storage media” (Compact Flash Card, Smart Media Card, etc.) as a “jpeg” file type. An image can recorded and saved as different types of files. A similar analogy is the way a crown can be made as gold, porcelain fused to metal, all porcelain, etc. An image file can be a jpeg, bitmap, tiff, raw, or several other types of image files. Jpeg is the most common type. This type of file allows a computer, such as the one in your office or the one found inside the digital camera to compress the image so that it is reduced in size, as it is stored on the storage media, by different amounts. The more the image is compressed the smaller the image file will be so it takes up less space. This allows you to take more images on the same storage media before it fills up and the images have to be downloaded to your computer. This means the storage media acts as reusable film. But compressing the file does come with a cost. While compressing the file allows you store more photos on a given storage media, it also reduces the quality of the images. The files are compressed by removing bits of data from the image. These small bits of date are the small details that make up the quality of the image. So the more the image is compressed the less space, in other words “memory”, it uses but the amount of detail in the image decreases as well. Different cameras have different amounts of compression capabilities. The Canon 20D has six levels of compression capabilities along with RAW and combination RAW + jpeg settings that I will discuss in just a moment. The amount of compression is named as large, medium, and small. The name refers to the image size, not the amount of compression. Setting the image “quality” to large means that it has very little compression so the image is large in size and the quality is very high. Like wise setting the image to small means the image will have a great deal of compression so the image size will be small and contain very little detail.
A second file type found on the Canon 20D, and some of the other latest SLR models and brands, is the RAW setting. In this file type the image has no compression at all. While the files do contain all of their detail they are very large in size. The RAW format is also not read by most imaging software. Because of these two factors I personally never use it. Keep in mind that the AACD now requires a RAW format image for accreditation.
So now that we have discussed all this, what size should you use? Well, that depends on what you want to use your files far. A general rule to follow is to use the large setting for printing, the medium setting for lab communication, and the small setting for email and web use. But these are very basic guidelines. Personally, I keep my camera set to the largest file size with minimal compression. For those of you who have attended my marketing lectures you know that I do a lot of printing at 13” x 19”. I print all my own office art. This is made from portraits taken of my patients that we print and they write a testimonial on. But that is for a future article. To print this size the image file needs to be very large. More than once I captured images on the medium setting to save space because I was photographing shade tabs of a patient’s case. I then went immediately to a portrait photo shoot and forgot to change the quality setting to large. I did not realize this until after the shoot. But now the patient had left and the image files were too small to print at a very quality. So now I just leave my cameras o the large setting at all times. I bought a 300-gigabyte hard drive for $280 at best buy and increased the memory on my server to 100 gigs. So now I wont have to worry about the size of my images for several years.