Stock Photography - JPEG and RAW Formats
Stock Photography - JPEG and Introduction This tutorial is aimed at those people who have an interest in digital photography, therefore we’re going to limit our discussion to the two file formats that are most important to photographers – JPEG and RAW. JPEG is a compressed file format that is an industry standard, and thus can easily be viewed by any computer and on the Web. Due to being compressed, JPEG files take up far less space than RAW files, but contain less detail and are lower in quality. RAW format refers to an uncompressed file that preserves a high dynamic range of detail in your photo. RAW files are very large, and have to be converted before they can be viewed on a computer, or printed. If you don't want to deal with converting your files later and have limited space, shoot in JPEG format. If high-quality photos are your main priority, shoot in RAW format. JPEG JPEG (named after the Joint Photographic Experts Group who created the standard) has been adopted as an industry standard file format for storing digital photographic images. There are several file extensions for this format, but ‘.jpg’ is the most common. JPEG uses lossy compression to reduce the size of a graphic file by discarding some of data that contains details in the image that the human eye cannot see very well. These areas include small color details as well as small details of light-and-dark. JPEG’s lossy compression works best for photos with smooth variation of tone and color. Lossy compression eliminates redundant or unnecessary information, resulting in a file of a much smaller size. This makes JPEG an especially useful and popular format for storing and transmitting images on the internet, where smaller file sizes are important. When a JPEG file is created (or an image is converted from another format to JPEG), you can determine the quality of the JPEG file by adjusting the amount of compression used. Keep in mind that creating the highest quality image possible will result in a large sized file. On the other hand, sacrificing some image quality will allow you to create a JPEG file that is much smaller in size. Warning: JPEG files lose some image quality each time they are edited and saved. So, edit your image first in a lossless format (TIFF or RAW, for example). Then, when you’ve made all your edits to your satisfaction, save the final image as a JPEG file. RAW RAW image files are primarily used by photographers who desire complete control over their image. RAW files preserve the maximum amount of image detail possible, resulting in higher image quality. However, preserving all this data means RAW files are typically very large. Nearly all digital cameras can process the image from the sensor into a JPEG file using the settings (white balance, color saturation, contrast, and sharpness) that were selected on the camera when the photo was taken. Cameras that produce RAW image files save all the resolution data (some of which would be lost when an image is converted to JPEG format), and also save the settings (without applying them to the image). Think of a RAW image file as the digital equivalent to a negative in film photography. Similar to a negative, a RAW file is not directly usable as an image, but contains all of the information needed to create an image. Like a negative, a RAW digital image contains more information than will usually been seen in the final processed image. So, a RAW image is a file that contains unprocessed data. It contains the full resolution data captured by the image sensor of a digital camera. In addition, all the settings surrounding the capturing of the image (aperture, shutter speed, white balance, contrast, sharpening, and saturation values) are preserved in the file, but not applied to the image. To produce an image from a RAW file, the file will have to be converted and processed. While all this results in an extra step for the photographer, it allows for complete control over the finished image. There is no single raw format. Each manufacturer uses their own proprietary formats, which are collectively known as RAW. This means that only the camera that captured the photo can understand the information collected on its sensors. FYI: Cameras that support RAW files typically come with proprietary software for conversion of their raw image data into standard RGB images. However, third-party processing and conversion programs and plugins are available from vendors that have either licensed the technology from the camera manufacturer or developed their own processing algorithms. Should I shoot in JPEG or RAW? Whether to shoot in JPEG or RAW all depends on what you plan to do with the images you shoot. If you are taking snapshots of a family picnic for your blog, JPEG will probably be fine. (Unless you plan to do a lot of post-processing and editing on the photo before saving it as a JPEG to upload to your blog). Shooting in JPEG mode will also allow you to store many more images on your camera’s memory card. Many digital cameras today have the ability to save images both as JPEG and RAW. While this takes up a lot of space on your memory card, you can view the JPEG version immediately on your computer, and also have the option to adjust the RAW file if you wish to. Shooting in RAW will take up a lot of space on your camera’s memory card. Converting and then processing the RAW files before saving them in a format such as JPEG also entails extra time and effort. However, photographers who want the maximum control over their final image shoot in RAW due to the flexibility it gives them in altering and adjusting the image in post-processing. |