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|| SportsShooter.com: News Item: Posted 2004-05-30
Pushing Pixels: Time to go RAW?
By Reed Hoffmann, Blue Pixel
RAW. You've probably heard people talk about it and read about it on discussion lists. According to some folks, it's the ONLY format to shoot in, and anyone not using it must be an idiot or a moron. I guess I'm both. For me, RAW is a powerful tool, but one that I choose to use when it benefits me most. As with most things, it has advantages and disadvantages. To know when to use it, first you need to understand what it is and how it works.
RAW is simply another file format, and most digital SLRs offer this as a choice along with JPEG and often TIFF. To understand RAW, it's important to understand the steps a digital image goes through inside the camera. Here's a simple overview:
1 - When you take a photo, you expose the camera's sensor to light, and the pixels on that sensor then collect that light to create an analog digital signal.
2 - That analog signal goes through an analog to digital signal processor and is converted into 0s and 1s, becoming a digital file.
3 - At this point there are two ways the camera can handle the file, based on how you set the camera:
A - In most cases, the digital file is processed for color, tone, noise, sharpening, etc. creating a finished digital photo, then saved as either a TIFF or a JPEG file. It's worth noting that the only difference between a TIFF and a JPEG is that the JPEG has been compressed, at a level chosen by the user.
B - If, however, you choose to have the camera save the image as a RAW file, you're telling the camera to write the digital information it collects from the sensor (those 0s and 1s) to the card with very little processing. You'll then have to do that processing yourself at the computer using special software.
With that in mind, it's obvious that capturing images in RAW format will add to the time required to turn the image out. It also creates a file that's larger than a JPEG file (though smaller than a TIFF), thus reducing the number of frames you can shoot before filling the buffer (since it's a larger file), makes higher-capacity cards (fast 512MB, 1 GB or larger) a necessity and requires more hard drive space and more archiving space. Sounds like a lot of drawbacks, right? Shooting in RAW format is definitely more work than shooting in JPEG. So why would anyone want to do it? Let's take a trip down memory lane.
Ah, the good old days of color negative film. Exposure? Just get it close, the film's got plenty of latitude to let you correct exposure mistakes. White balance? Who cares? As long as you're shooting available light, just fix the white balance when scanning.
If you were really conscientious, you even gelled your strobe for fluorescent or tungsten light. Life was easy. Then digital arrived. Suddenly you had to remember back to those rare times you had to shoot slide film. "Yikes! You mean my exposure has to be exact or my photos are ruined? And please don't make me shoot in artificial light! I have to carry and use all those filters and gels and strobes to get the color right."
With digital, sloppy exposure and white balance creates images that are hard to handle at best and unusable at worst. Better learn to use those histogram, flashing highlights display and custom white balance settings.
Now what if we could take all the great things we love about digital and go back to shooting the way we did with color negative film? In other words, be a bit sloppy again. That's what RAW format's all about.
When you shoot in JPEG or TIFF mode (and I see very few reasons to ever shoot TIFF), you're locked into the processing parameters of how you set the camera before you press the shutter button. White balance, tone compensation, sharpening, etc. are all applied in-camera, and if you make a mistake, you've got to try to fix it in Photoshop.
Remember, Photoshop is a destructive application. Everything you do in Photoshop takes information away from the file, even if you make it look better. But what if you shoot in RAW format?
Capturing photos in RAW format means that none of that processing has happened yet. When you view the image in a browser like Photo Mechanic, you're simply seeing the image the way it would look if it was processed with those settings applied. Using a RAW file editing program (either a manufacturer's like Nikon Capture or Digital Photo Professional (Canon), or Photoshop's Adobe Camera RAW editor), you can change those settings in any way you want, and are merely changing the interpretation, or rendering, of those 0s and 1s. There is no loss of image data or quality. Cool, eh?
Here's the scenario I like to use in explaining when you might want to use RAW. Imagine you're covering a trial, waiting outside the courtroom for the verdict. Shoulder to shoulder with the TV folks and their hot lights, in a fluorescent-lit room. People come out, you start backpedaling and shooting. The crowd moves down a hallway with windows to the side and sunshine streaming in. From there to a tungsten-lit foyer, then outside to stop under a tree for interviews. What white balance do you choose for this? No choice is right, since the color temperature is constantly changing. I used to handle that by putting the strobe on and cranking the power, so the strobe overpowered all else and I just had to worry about the background. Now I simply shoot in RAW format and set the color balance later. It even gives me the ability to adjust my exposure some.
This is the beauty of the RAW file format - it gives you the opportunity to optimize the image before bringing it into Photoshop, so you can end up with a better quality image. And it's going back to the future.
Those of you who used the NC2000 remember the Kodak Acquire software. It was RAW file editing software, as the NC2000 only saved RAW files. Photo Mechanic had the ability to process those RAW files as well, and added an exposure slider. Using either of those packages you essentially prepped an image before bringing it into Photoshop.
As camera designs advanced, manufacturers moved to JPEG as the main format, though they still offered RAW. Creating an in-camera JPEG made for smaller files, allowing for more images per card and faster capture.
These days, we're seeing RAW becoming a more useful format, as buffer sizes increase, card prices drop and computer processors get faster. The Nikon D70 offers only JPEG and RAW formats, with no TIFF option. I expect to see much more of that. There's no faster way to get a photo out than JPEG in-camera, and there's no better quality than RAW, Say "goodbye" to TIFF.
The other change we're seeing is more and more cameras that allow you to capture images in both RAW and JPEG at the same time (some of the Canon EOS digital cameras as well as the Nikon D2H and D70). Every time you press the shutter the camera can write both the RAW file and a JPEG of the same image to the card. This gives you a JPEG for fast viewing and/or use and a RAW file in case there are any problems. The downside is it requires more card space to write the additional files. 8GB cards, anyone?
RAW isn't the answer to every image problem. It won't let you change shutter speed, f/stop, ISO or focus after the fact. It will add to the time it takes to get a picture out of the computer. You have to have special software (either the manufacturer's or Photoshop's Adobe Camera RAW plug-in (if it supports your camera, and is included in CS), and have to learn how to use that software.
RAW format is simply another tool we have available, and one you should become familiar with. It's only going to become more and more important as digital cameras and digital photographers mature. And who knows what the future will bring? RAW software can do things we didn't even dream of. If you've got a Nikon digital camera, check out what Nikon Capture will do to a backlit RAW image with Digital DEE (Digital Dynamic Exposure Extender). And if you want the BIG wow factor, check out how Capture can correct the distortion in an image from the 10.5mm lens. This is cool stuff, and will only get cooler in the future.
Is RAW the answer to everything? No. I still shoot most of my assignments in JPEG, being careful to set the white balance properly and get the exposure right, because I can fly at getting those images out. But for jobs where color and exposure are tricky, I run straight to RAW. My goal is always to make the best possible photo and deliver it as quickly as possible.
Remember, digital is simply a tool to help us make photos. Out goal should be to understand how it can help us in the best ways, so our attention stays focused on making great images, not being great technicians.
(Reed Hoffmann is a former newspaper photographer and current member of Blue Pixel (http://www.bluepixel.net), a digital photography and consulting group that's worked with over 30 newspapers around the country to help them improve image quality. He will be leading a breakout class at the Workshop & Luau titled: "Doing Digital: It's Now All About Quality".)
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