Camera RAW 101: Why Shoot RAW?
Although blogs and websites are great ways to pick up snippets of useful information and insights, reading (and writing) photography books can help put a lot of complex information into perspective. My newest book was published by Amphotos Books in August.
Entitled Camera Raw 101: Better Photos with Photoshop, Elements and Lightroom, it was written for any digital photographer who is interested in going beyond the preset options in the camera and is ready to take control over the creative process. The book provides the information you need to make RAW work for you, including setting up a preliminary workflow, using and automating Adobe Camera RAW, and basic and advanced conversion options. The book also includes a detailed comparison of Adobe Camera RAW features in Photoshop Elements and Photoshop CS4 and Lightroom 2.1. In the following excerpt from the book’s introduction, I explain why you should shoot RAW and suggest when RAW isn’t the best choice.
RAW files shouldn’t be seen as the lazy person’s way to great images, though. A poorly composed image, an out-of-focus image, or one with gross exposure errors isn’t going to be magically transformed into a quality photograph because you were able to edit the RAW file. It is the responsibility of the photographer to capture the best possible image at the time of capture.
Advantages over JPEG and TIFF: RAW files free the photographer from having to be satisfied with what the camera thinks are the correct values for sharpening, noise reduction, and white balance. The differences can be startling! Since this information is all stored in addition to the file, it becomes possible to make changes to them after the fact. This is where the RAW format becomes so valuable.
When shooting in JPEG the camera processes the color values based on the current white balance setting in the camera to create a final image. The file is then compressed to save space using the current quality setting in the camera. RAW capture, on the other hand, does no color interpretation in-camera but depends on the RAW converter software to handle this task. Hence, you have much more freedom after the capture to either fine-tune the image or make corrections to basic problems, such as improperly set white balance.
RAW is the only capture method that preserves the full color fidelity of the image. With JPEG, you automatically throw away one third of the color information in your image. The sensor in most cameras records data as a 12- or 14-bit file, giving each pixel one of 4,096 levels or more of color. To take advantage of this, you’ll need to shoot in RAW mode. JPEG only supports 8 bits per pixel, reducing the possible colors to 256 per pixel. Less color information means that yu have less latitude when editing the image for final output.
JPEG is a lossy compression method. Every time a file is saved in the JPEG format it loses a little more fidelity.
JPEG and TIFF also apply sharpening and noise reduction at the time of capture. If you’ve set these incorrectly, and don’t catch the error, you have little choice in the edit phase. I strongly feel that the camera does not know what my intended use for an image is and should never be allowed to choose the sharpening or noise reductions it “thinks” I want.
Saving in camera in TIFF is becoming much less common in recent cameras. Although some, such as the Canon DSLRs, actually tag their RAW files as TIFF, these are not true TIFF files. TIFF, or Tagged Image File Format, is a standard file type for bitmap, or raster, data. Unlike JPEGs, TIFFs are not subject to lossy compression or to only 8 bits of color information. The file sizes are large; a 16-bit TIFF file will be about three times the size of the same RAW file, because TIFF is saved to 16 bits rather than the 12 or 14 bits recorded by the camera. The extra bit depth is an advantage over JPEG, but the same control issues that JPEG suffers from are present in TIFF capture as well. Color balance, sharpening, and noise reduction are all applied directly to the image at the time of capture. The only advantage that TIFF offers over JPEGs is color fidelity and lossless compression. To be honest, I can’t think of a single instance where saving a TIFF file in camera is a good option.
When RAW isn’t the Best Choice: There are times when the extra work involved with RAW processing can’t be justified. As an example, photojournalists will typically shoot in JPEG when shooting for assignments. The image files are smaller, important for quick transfer to the newsroom, and the JPEGs can be used with little or no extra work before publishing. Another time when JPEGs may be a better choice is when you are shooting youth sports events and want to make prints for sale right at the site. This is another case of speed being more important than quality.
I love to share information on digital imaging and photography, and I hope my new book reflects this passion. I’d love to hear from you with comments about Adobe Camera Raw or to share your experiences.
JPEG or RAW: Which Should You Choose?
Decisions made during image capture can have a significant impact on post-production costs and the quality of the finished prints. Two of the most important decisions we make during image capture are which file format and color space to use. Many cameras, particularly DSLRs, allow us to capture images either as JPEG, TIFF, or RAW files. They also allow us to choose to work in the sRGB, the Adobe 98 RGB, or a custom color space.
In terms of cost and quality, the Great Divide lies between JPEG and RAW file capture. It’s easy to understand why many photographers would naturally gravitate toward JPEGs. JPEGs are a compressed file format that reduces file size and increases rate of capture. JPEGs are fast, and in some ways more convenient in terms of storage and computing power. With modern in-camera automatic exposure and color correction, JPEGs can deliver good image quality.
But JPEGs have some important limitations. For example, in a recent article in Photo Techniques magazine, Timothy Edberg noted that the cameras he tested produced images with at least one f-stop less dynamic range in a JPEG file compared to a RAW capture. This makes sense, as an 8-bit JPEG digital capture uses lossy compression. A RAW file typically uses no compression, or lossless compression.
Additionally, an 8-bit JPEG file contains about 256 tones per color channel and a RAW file shot in 14-bit contains just over 16,000 tones. A 16-bit file RAW file has over 65,000 tones per channel. In color editing and in the final print, this can make a huge difference in the appearance of intense colors, such as open skies.
Not only that, but the default setting for JPEG capture is the sRGB color space. This color space is fine for digital images that will only be viewed on a computer display, but sRGB is not ideal for printing. The Adobe 98 RGB color space is significantly larger.
JPEGs also aren’t as versatile as RAW files. RAW files are very flexible, while JPEGs are pretty much locked in. With RAW files, it is much easier to correct color casts or make adjustments in certain colors or the overall color temperature, color balance, exposure, and contrast/levels.
Color artifacts and distortion in details will also be visible much sooner in a JPEG file than in the RAW. The distortions may show up in high-contrast transitions first, but can appear anywhere in the image.
Some photographers object to using RAW capture because it produces “big files” and slows the computer. Given the improvements in computer hardware and falling costs of memory and hard drives, it just doesn’t make sense to accept the limitations of JPEG capture for most uses.
Conclusion: JPEGs are fine if you plan to go straight from the camera to publication. You’ll probably want to use RAW if you plan to edit your images post-shoot.
You can find more details on the basics of RAW file processing in my book Mastering Digital Color published by Thomson Publishing.
