At a basic level, yes, you have to shoot in RAW: every digital camera starts out by producing a RAW file. If your camera automatically produces a jpeg file without offering an option to save as RAW, then the rest of this discussion is just theory. But if you can save the RAW file, read on: RAW may not be for you, but the decision is important. What is RAW?
RAW is any one of a number of propriety file formats that contain all the available data captured by the camera's image sensor when you pressed the shutter release. They are totally unprocessed , uncompressed, computer files (Nikon and Kodak actually use a slightly lossy compression algorithm when saving raw files).
Every camera manufacturer has its own native RAW format: Canon RAW files use the .crw and .cr2 extensions, Nikon cameras create .nef files, Kodak’s is referred to as .dcr. All are unique, proprietary, incompatible with each other, and subject to change without notice.
Many cameras can save both raw and JPG files simultaneously, providing a ready-to-use image for many applications, while a RAW file is available for later and more comprehensive processing. The only downside to this double format is the extra space that it takes on memory cards.
Disadvantages of Working in RAW:
First and foremost is the time it takes to save each image on your camera. Most modern cameras can save even large JPEG images as fast as you can press the shutter. On a 6-megapixel camera, each RAW image takes about 40 seconds to get saved to the memory card.
The camera has a built in memory buffer to hold the image until it has time to get it onto the card, which masks this time lag...until the buffer is full at maybe 4 or 6 images. Part of the cost of more advanced cameras is in the processing and buffering of images. At the other end, transferring the images from the card to the computer is also noticeably longer. Faster cards are reducing these times, but compared with JPEGs they are still long.
File size is another consideration. High-quality JPEG images take up about 2.5MB, but the RAW file they were converted from is more like 4.5MB. It is often argued that this is offset by the falling cost of memory cards and computer drives and their increasing capacities. Oddly, as memory gets cheaper, RAW files get bigger! And the biggest drive always gets full before you expect!
Using RAW means that your digital photos won't be processed and compressed by the camera That's important if you plan to do a lot of editing.
Every RAW file has to be converted to another format before it is viewed or printed. Even the image you see on the camera’s LCD is a bit-mapped representation of the RAW file (like a little jpeg). That means a big increase in time spent in front of the computer, compared with shooting jpeg of even tiff files, which a few cameras can do. And that means having to manage your work flow efficiently...which isn’t such a bad thing.
Obviously there must be advantages, too. There are, and for many photographers, they are compelling. The easiest way to get to terms with the pluses is to compare RAW and the most common file format for photographers, .jpeg.
JPEGs and RAW:
JPEG photos are processed images: the white balance has been adjusted, colour correction has been applied, the image has been sharpened, and the saturation adjusted. One of the disadvanages of shooting RAW is that you have to make all these decisions about every image.
RAW files are roughly analogous to the difference between an undeveloped film and a developed negative: you can crop, dodge and burn the final print from that negative, but since the negative has already been processed, you’ve given up all the control you could have exercised over the choice of developer, temperature, length of time in the developer, etc.
If detail has been lost from the negative, there's no print process on earth that will bring it back.
RAW files preserve all of the colours originally captured by the camera at 12 or 14 bits per pixel; a JPEG is reduced to just 8 bits per pixel. That means higher colour fidelity and more room to move when you edit your images.
In saving the file as a JPEG we are trusting the raw conversion to a program on a chip built into the camera; a much less powerful system than your computer. If we the file is saved in raw format that more sophisticated platform will handle the conversion. What’s more, if needed, it can be converted again and again if you like, and to any format you want...tiff, for instance. With a JPEG out of the camera, that choice is made and you are stuck with it.
So what are you "stuck with"?
When a digital camera makes an exposure the imaging chip records the voltage level generated by the light at each pixel. The analogue to digital (A/D) circuitry now converts this voltage signal into a digital representation as either 12 or 14 bits of data.
If you've saved the file in raw mode, when it is subsequently loaded into a raw conversion program and then saved to a TIFF or .PSD format file you can export a 16 bit or even 24 bit TIFF. The 12 or 14 bits recorded by the camera are then spread over the full 16/24 bit workspace.
If you save the file in-camera as a JPEG than it is converted by the camera's software to 8 bit mode and you will only ever have 256 brightness levels to work with.
You can’t print these high data files: they will still be rendered as 8 bit files by your printer, but you get to choose which bits to use and how!
If the camera records 12 bits of data then each pixel can handle 4,096 brightness levels (2^12). A 14 bit system records 16,384 different brightness levels (2^14). This translates to the following values:
For the brightest tones, a 12 bit RAW file gives 2048 levels ; an 8 bit JPEG has 69
For the bright tones, it’s 1024 levels vs 50
For the mid tones, 512 levels vs 37
For the dark tones, 256 levels vs 27
For the darkest tones, a 12 bit RAW file gives you 128 levels to work with against 20 for the JPEG
There is nothing wrong with having a great image in JPEG form. However if you don’t save the RAW file, then when you pressed the shutter release, you locked yourself into several important decisions about the final image quality, namely white balance, overall contrast, colour saturation and the like.
With a RAW file you are free to change your mind about these settings at any time. On the plus side, JPEG files may require little or no additional processing when adjustments are made in post-processing. This is just as well, because processing artefacts are much easier to introduce.
RAW file never change. Sharpening, contrast and saturation settings, colour temperature / white balance, and so on are only tagged onto the raw image data to tell the computer how to display the image. Changes are incorporated into exported jpeg/tiff etc. files during conversion, leaving the original RAW as it was. Every time a JPEG is saved even when no changes have been made, a little data is lost and the image degraded a bit more. For some photographers, the ease and speed of use is sufficiently valuable and the degradation small enough, to offset this problem; for others not. Certainly anyone looking for the best possible image quality will want to shoot in raw mode whenever possible.
Working with RAW File:
There is nothing different in moving RAW files from the card. A cable, memory card reader, even wireless, if your camera offers such a feature.
Just about any image editor released in the last couple of years will handle RAW files just as if they were JPEGs. No matter whether you use Adobe Photoshop Elements, Microsoft Digital Image Suite, Corel Paint Shop Pro, or Ulead PhotoImpact you'll get RAW support if you upgrade to the newest version. As new RAW formats are released, the best packages add support for them...at least, for the most popular camera brands.
MAC and Microsoft Windows Vista understands RAW, but if you still use XP you will need to download the free program update from Microsoft Powertoys site to see RAW images in the file explorer and file viewers. Stand alone viewers like XNView and Picasa (both free) also recognise and can adjust RAW files, exporting the resulting files as JPEGs or TIFFS.
Depending upon what program you use to edit RAW files, your experience will vary. Most programs allow you to make some initial adjustments to your RAW photo before loading it onto the editing canvas. Paint Shop Pro, for instance, opens RAW images in a comprehensive editing window where you can adjust the white balance, exposure compensation, and sharpening, colour balance and other attributes; it is actually part of the standard editing program. Photoshop Elements also offers a powerful interface that lets you work with with the image's histogram before loading it into the editor. Canon includes a comprehensive editor with it's cameras capable of batch programming and easy scripting.
Reasons to Shoot JPG:
— Files are smaller and therefore more of them fit on a card and they load faster.
— Image quality is more than adequate for most applications.
— Small files are more easily transmitted wirelessly and online.
— Many photographers don't have the time or inclination to post-process every file.
— Many cameras can not shoot quickly enough in raw mode.
- Many models don’t support raw.
Reasons to Shoot Raw:
— A raw file holds exactly what the imaging chip recorded. Nothing more. Nothing less so you can extract the maximum possible image quality
— Raw files have not had while balance set. This allows one to set any colour temperature and white balance after the fact with no image degradation.
— File conversion is done with a much more sophisticated algorithms than possible in camera.
— You have a 16 bit image with 65,536 levels to work with compared to a JPEG’s 8 bit/256 brightness levels. This is especially valuable when trying to open up shadows or alter brightness in any significant way.
Should You RAW?
If you already have an image editor and a camera with RAW capabilities, why not? Give it a spin and see if you like it. If you don’t spend much time editing your photos, using RAW may require more time and effort than it's worth to you.
