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TECHNIQUE – Top 5 Tips for Quality Image Files (part 1)

Active crater of Poas Volcano, Costa Rica

Active crater of Poas Volcano, Costa Rica

If you’re looking to take your photography to the next level, maybe even becoming a part-time or full-time pro or perhaps selling some prints, I think there are five things that you should be doing in-camera to ensure that you take advantage of the image quality that your camera has to offer. So, without further adieu, here are my top 5 ways to get great image files.

SHOOT RAW

You don’t have to shoot in RAW; JPEGs are quite capable of producing good images. If you’re a hobbyist and want to produce pictures ready to print and share, get out there and shoot some great pictures in JPEG. But if you’re looking to take your nature photography to the professional level, RAW is for you. Why? JPEG files don’t make use of the vast majority of the information that modern DSLR cameras are capable of capturing; RAW files do and that translates ultimately into more control over image optimization and higher-quality large prints.

Here’s how it works. Each pixel on your camera’s sensor consists of three color channels — red, green, and blue. JPEGs are 8 bit files, which means that 8 bits of binary information (1s or 0s) are possible for each color channel. Raising 2 to the 8th power (for each channel, either a 1 or a 0 is possible 8 times) gives 256 possible combinations for each color channel. Since there are three colors, we take 256 to the 3rd power (red, green, and blue), which yields a total of around 16.7 million possible color values in a JPEG image. Doesn’t sound too bad, right?

But now let’s look at RAW files. Most cameras these days capture RAW files with 12 bits. Using the same math as above, we have 12 possible binary outcomes for each color channel. So, 2 to the 12th power is 4,096. If we take those 4,096 possible tonalities for each color channel and look at all of the possible color values for the three color channels combined, we can take 4,096 to the 3rd power. This yields over 68 billion color possibilities. So, a RAW file has over 4,000 times as much potential color value information as a JPEG file. Put another way, if you shoot JPEG, you’re only using about 2.5% of the possible color information that your camera is capable of recording!

In addition, JPEG files are compressed in a lossy fashion, which means that some of the relatively limited information captured in the first place is thrown away to keep file size smaller. So, on top of the fact that JPEG files start with less information than RAW files, they then throw away some of that information during the compression process. Do note that RAW files also are compressed but using mathematical algorithms that are lossless, meaning that no image data are thrown away in compression in order to reduce file size.

Since JPEG files offer less information for editing in the computer, you’ll most likely want to have the images come out of the camera with saturation and sharpening already applied. Unfortunately, you may or may not like how your camera handles this “post-processing.” Most pros want to be in control of how their images look when they go on the web, for fine art printing, or for a magazine or coffee table book. RAW files take advantage of your camera’s sophisticated image capture capabilities and allow you to stay in control of optimizing your images in the computer.

Posterization is a common symptom when processing a JPEG file of a picture with a colorful sky. Because such skies, especially if the sun is in the frame, exhibit a myriad of very subtle tonal gradations, making changes with limited information can result in image degradation. Because a JPEG file contains much less information than a RAW file, processing it can turn these subtle gradations into abrupt transitions. By way of example, take a look at the comparison below of a sunset image I took in the mountains where I live in Costa Rica. I needed to bring down the highlights and up the saturation in the sky a bit. Processing the RAW file was no problem. When I processed a JPEG version of the RAW file (remember the JPEG has much less color information and is being processed in an 8-bit environment), however, posterization started to become evident. And when I processed a 16 color GIF version of the file, well, let’s just say that only Seurat would be happy with the result! The lesson, the more information you start with, the better your final result.

processed raw                              Processed RAW file

3_processed raw_1435011443455Processed RAW file, zoomed in

presentation_templateProcessed JPEG file

5_processed zoom_JPEG-closeupProcessed JPEG file, zoomed in

presentation_templateProcessed GIF file

processed raw photo

Processed GIF file, zoomed in

In addition, RAW files, with their vastly greater information, also give better results when upsampling a file beyond your camera’s native sensor resolution, a necessary practice for selling large fine art prints or doing a gallery exhibit. By way of example, I shot the cloud forest image above with a Canon 20D, an 8 megapixel camera. I was able to work from the RAW file and upsize it for printing at 30 x 45 inches for my gallery exhibit at the Missouri Botanical Garden in the US a couple of years ago. This is fairly extreme upsizing, but the image looked great in the exhibit hall.


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About the author Gregory Basco
Like many nature photographers, I started my career doing something else. A political scientist by training, my research focused on the politics of the environment in Latin America. I researched environmental politics and ecotourism in Costa Rica and worked here for a number of years as a conservation professional, having first come to the country in 1992 as a Peace Corps volunteer. I now dedicate myself full-time to my own photography and my Costa Rica photo tour company. I work out of my home office in Costa Rica’s central highlands, where I live with my wife, twin boys, our dogs and cats, and various hummingbirds and songbirds that visit our backyard feeders. Visit Greg’s galleries, store, and workshops at Deep Green Photography.

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