Today is National Peanut Butter Cookie Day! This delicious food holiday lets cookie lovers and peanut butter lovers step away from pies and cakes to indulge in a little peanut butter and cookie therapy. In honor of this day, here’s a guest post about cookies and cakes and how it relates to digital photography. PS: One of the suggested names for Barry Staver and my podcast is “Pixel, Grain and Cookies.”
Today’s Guest Post by Barry Staver, photography by Joe Farace
“A balanced diet is a cookie in each hand,”—Barbara Johnson.
It seems redundant to say it but digital imaging is different and more convenient than film photography. The ability to select a white balance, choose a favorable ISO speed and view images on the fly are just a few reasons. To put these tasty morsels in play, we’ve had to expand our horizons and elevate our learning curves. And then there’s the inevitable question of what to shoot: JPEG or RAW?
RAW vs, JPEG
If you already didn’t know it, JPEG is an acronym for the Joint Photographic Experts Group who created the standard in 1986 for the compression of still images. JPEG specifies a file format that’s used the codec (code-decode) that defines how an image is compressed and decompressed into a final image. To accomplish that, your camera makes adjustments by eliminating colors the eye can’t see and then compresses the image using a reduced color depth to save the image in the JPEG format.
Because this process discards what it decides is unnecessary, JPEG is often referred to as a lossy (not lousy) format. Keep in mind, however, that when the file is opened in a computer the lost data is, for the most part, rebuilt, especially if a low compression ratio was used. Image compression ratio is the relationship between the size of the original image and the size of the compressed file. It’s often expressed as a ratio, like 10:1, where the original image’s size is ten times the compressed size. A higher compression ratio means the file size is smaller, but potentially with some loss of image quality. JPEG files can achieve ratios of 10:1 to 20:1
How I Made this Photograph: This flower was captured with north window light in the kitchen of my former home with a Leica R9 and Digital Modul-R digital back with a 100mm Apo Macro Elmarit f/2.8 lens. The image was made in Aperture priority mode with an exposure of three seconds at f/22 at ISO 100 and was captured in Leica’s preferred RAW format—DNG.
DNG, aka Digital Negative, is a RAW image format that was developed by Adobe and is designed to be a universal format for storing raw image data. Leica uses it because DNG files are usually compatible with most image editing software, making them easier to work with than proprietary RAW formats. Leica DNG files don’t require separate sidecar files, like XMP, to store additional information and are backward compatible with older software like the Photoshop CS6 that I use.—from Joe
Continued..
Unlike JPEG, RAW requires little or no internal processing by the camera. These files contain lots more color information, providing more data but that data now requires external processing. When choosing RAW all of the data from the camera’s sensor is saved without any processing. Effects such as Contrast, Saturation and Sharpness are not applied to the image file.
Perhaps these food analogies will help explain the difference between a RAW capture and a compressed (JPEG) capture:
Cake. You can purchase one ready to eat in a bakery or make one at home from scratch. The store bought cake is like the JPEG, since most choices are already made for you. The bakery decides what ingredients to add in what quantity to meet their standards. JPEG photographs are processed in-camera and compressed. You take it as is. On the other hand the scratch-made cake allows you to choose the ingredients, altering them to suit your personal taste. The same thing goes for RAW images.
Chocolate chip cookies. Off-the-shelf brands have chips that are baked into each one, the softness of the cookie predetermined and all are uniform in size. This is clearly the JPEG version. Baked at home with almost any recipe gives you more choices: milk, dark, or white chocolate chips, the number of chips to fold into the batter and the size of the cookies baked. That’s the RAW version.
If you enjoyed today’s blog post and would like to treat Joe to a cup of Earl Grey tea ($2.50), click here.
Along with photographer Barry Staver, Joe is co-author of Better Available Light Digital Photography with “Other Used and New from $3.25.”