PAM243 submersible - converted from Raw to JPEG without further processing
RawSo what is a Raw photo? First of all, a Raw file isn't a photo yet. It's just Raw data. Name explained! You'll need a computer to turn that raw data into a photo. But why is raw data better? The raw data is - as opposed to the JPEG format - uncompressed lossless data. Exactly as your camera's sensor registered it. The settings that you used when you took the photo are embedded into the raw data file. E.g. the settings re the aperture, shutter speed, white balance, contrast, saturation and even the focal length and so on. Exactly this is what makes Raw so much better than JPEG.
You can change most of the recorded settings once you have the raw file on your computer to turn it into the final photo. Your camera just stored the parameters but didn't apply them yet. Just so you understand, when you shoot JPEG, your camera converts the raw data into a photo with its built-in software and processor. This is why a JPEG may appear to look better on your camera's display than a Raw file. But believe me, your computer has a lot more processing power and - with the right software - it does a much better job turning the data into a photo. And what's more important, it leaves you in control of the processing decisions.
In case you're thinking, "yeah but I can process JPEG files on my computer too". That's true, but the JPEG source file is already compressed, sharpened and so on by your camera. Basically you're starting out with a damaged file. But what's even worse is that saving a JPEG after changing it means that the file will be compressed again - that is what happens when you save a file as a JPEG. Compression upon compression is definitely not a good idea.
The Photoshop camera raw pluginThere's a lot of software available for processing raw data files. I use Photoshop CS4 and the camera raw plugin. There are different versions of this plugin available so make sure that you have installed the one that supports the data that is produced by your camera. Adobe is always quick to add support for almost any new camera on the market. Follow this link for information about the Adobe camera raw plugin and compatibility with your camera.
When you open a raw file with photoshop, the plugin user interface will appear. The screen grab below shows the controls that you can use.
You can see that the important information re the recorded aperture and shutter speed show at the top and that you can easily change many of the settings. And you can do that without affecting the quality of the raw data. It would go beyond the scope of this post to explain all the possibilities, but to show you how powerful the raw format is in combination with this plugin, have a look at the screen grabs below (click the images to see larger versions):
The photo as recorded with f5.6 1/30 s - without exposure correction
The photo as recorded with f5.6 1/30 s - one stop over exposed
The photo as recorded with f5.6 1/30 s - one stop under exposed
I'm sure that - even though the above screen grabs show just a very small part of what is possible - you'll agree that being able to change the exposure after taking a photo is nothing less than brilliant. Again, you're just changing the parameters without changing the recorded data so you're not degrading the original file.
The quality of Adobe's raw camera plugin is so good that I seldom have to make any changes once I've opened the file. I usually correct the exposure slightly when necessary, increase the sharpness and contrast and that's it. Once the file opens in Photoshop, I resize it and save it as a JPEG. Easy peasy.
DownsidesSure, there are downsides too. First of all you need a computer and good software to process the raw files. There's a lot of software available but I still think that nothing beats Photoshop and the camera-raw plugin.
Processing files can be time consuming. The raw data is uncompressed so it requires more storage capacity and it takes longer to copy the files to your computer. You'll need larger or more memory cards and more space on your computer too. Storing thousands of raw files can require quite a lot of space on your hard drive. Then again, you don't have to keep the raw files once you're done processing the files into the final photos.
Considering what you get in return, these disadvantages are a very small price to pay.
You can find an interesting PDF that goes into much more detail about raw capture and how JPEG differs from raw on Adobe.com: understanding_digitalrawcapture.pdf
Feedback is appreciated!