Digital Photography File Formats
If you want to get the most from your digital camera and your photos you need to understand digital photography file formats. There are several options when you are capturing images on your camera. Each one has advantages and disadvantages. You have to decide which is best for your purposes. In addition, you should understand the file formats that are supported on the web if you plan to display your images there such as sharing on social media or using them on a website.
Digital Photography File Formats
There are three file formats that are used most often in digital cameras for photo storage. Storage can be on internal storage or removable storage cards such as SD cards. Your camera may have a setting to choose which format is used to store your images. They are:
- JPEG- JPEG is short for Joint Photographic Experts Group. The JPEG digital format was first introduced by that organization in 1992. JPEG is one of the most common formats used in digital cameras. The JPEG format is recognized by almost all digital camera and software programs. JPEG is a lossy compression format. During JPEG compression, some of the image data is lost, thus the name lossy compression. JPEG files are smaller than the files saved with other formats, so you can save more images on a digital storage card than with either of the other two image formats. The tradeoff with JPEG is that it is harder to digitally manipulate the data in a photo editing program. Since some of the data is lost in the compression process image details, such as in dark and light areas, can be lost and are unable to be recovered. Many DSLR cameras allow you to store an image using JPEG, as well as one of the lossless formats. This is what I do. The reason becomes clear when you shoot in another format such as RAW. If you shoot only in RAW you have to open each image to view it in a program that can read RAW images. Shooting a JPEG image with the RAW image allows you to see a thumbnail image so you can choose the images you want to work on in your photo editing software. Another problem with JPEG images is that they degrade further each time they are saved due to the compression algorithm.
- RAW- The RAW format is uncompressed data. All the image data your camera captures is contained in a RAW image. This format is not recognized by all camera and software like JPEG images, and it takes a software program that can read these files to view them or edit them. Professional photographers prefer to use the RAW or TIFF formats for storage because the image files contain all the original data. This allows you to process the image files using a photo editing program and you have all the data available to use to do such things as recover detail in shadows and highlights. A lossy compression format such as JPEG loses some of that information in the process of compression. Once lost, those details cannot be recovered.
- TIFF- TIFF is short for Tagged Image File Format. As with RAW files, these files are lossless and uncompressed files. Both the TIFF and RAW formats create much larger image files than JPEG, so you will need larger storage cards to save the same amount of images. If your camera supports storage in the TIFF format the camera can produce thumbnails which can be viewed on the camera screen. Also, your computer can create thumbnails which you can view as you are searching for the photo you want to work on.
One note on storage cards is that today you can buy large storage cards inexpensively. You can buy a large card so that is not a consideration when choosing between digital photography file formats. For this reason, I recommend using either RAW or TIFF for image capture in your camera. These formats will create images of the highest quality. This is a consideration if you ever wanted to print the photo for display at a large size. It may not be a consideration now, but you never know what you might want to do with your photo in the future.
Digital File Formats For The Internet
Now let’s look at how you want to save your files for upload and use on the internet. You will need to save your files in one of the file formats recognized by web browsers if you want to use your photos on a website or upload to your social media page.
JPEG and PNG are the most common file formats used on the internet.
JPEG is the most commonly used image format for photographs on the internet. The compression creates a smaller file that takes less time to download when loading a web page. This is a huge consideration when you consider that if the web page takes longer than five seconds to load most users will click away from your page. The problem with JPEG compression is that the lossy format causes generational degradation. This means that each time the file is saved the image loses some quality. It’s for this reason that the original image should be saved in one of the uncompressed lossless formats and then saved as a jpeg image for upload to the web. It is also good to remember when saving JPEG images that the DPI setting should be set at 72 for use on the web. Web pages can only display images at 72 dpi, so saving the image at a higher resolution will only result in a larger file to load with no increase in image quality. You can save images at 150 dpi if you are saving for devices with Retina displays. JPEG format images are 8-bit images, so they are not true color images, although this is very hard for the human eye to detect.
PNG images, on the other hand, are true color images and support 16 million colors. PNG is used mostly for graphics on the internet where true color display is important. All modern browsers support PNG images, in addition to JPEG.
Now that you know about digital photography file formats and their use on the web, you can make a decision about which is best for you. Knowing this information can help you when you process your images, as well as when you are saving for use on the web or your social media pages.