The more advanced digital cameras allow you to store images in two common formats, JPEG or RAW.
But what is a raw image? Most photographers know all about the JPEG format but not necessarily the RAW format. Using the RAW mode has more advantages over JPEG, and should be the preferable method of saving your photos.
RAW images are digital photos which are uncompressed and lossless; everything the sensor of your digital camera detects is captured and saved as part of the file. To help understand this, a good analogy would be to compare this to traditional film photography. RAW images would be the digital counterpart of a film negative, while JPEG you could view as the digital counterpart of the end product of a photo once it was processed in a studio.
Digital cameras have the ability to manipulate pictures internally right after the photo is taken, including color temperature, exposure adjustments etc. These photos are then saved as a JPEG file, a compressed format.
On the other hand, cameras that provide RAW mode save the images as an uncompressed file. Compression reduces the size of any file, and as such, RAW image files are larger than the compressed JPEG files but offer much higher quality. To give you an idea, if your JPEG file is 2Mb, the RAW file would be around 10Mb.
Different camera brands have different file extensions for RAW formats, but most photo editing programs are able to import and process the majority all of these. You would use an image editor to manipulate the RAW files.
How is a RAW vs. JPEG processed in the camera?
First of all, a digital camera records the light that hits the exposed imaging chip, usually a CCD, and registers it in each pixel or picture element. This recorded light information is then converted to voltage levels, and these voltage signals are then represented as digital information through the camera’s circuitry. Up to this point, the same process occurs whether your camera is set to capture JPEG pictures or RAW pictures, but the difference comes in the next step.
Saving pictures in the RAW format by setting your camera to RAW mode allows the pictures you took to be sent to a RAW conversion program. The camera then creates a file which has all the settings in your digital camera, including color temperature, contrast and saturation, white balance, and other settings depending on the capabilities of your camera. The RAW image is, of course, not edited in any; these settings will all be included in the raw image data. All of this data is then saved to the memory card as a RAW image file.
If however, you had your camera set to save JPEG files, the camera will use all of its features to enhance and hopefully produce an end product that you may not have to edit any further.
The digital camera will then sharpen the images by using USM or unsharp mask, enhancing the contrast between dark and light edges in the picture. Some cameras also allow manipulation of contrast and color saturation. Finally, the camera will then compress the image and save a JPEG file.
To summarize, a RAW file captures all the data from the imaging sensor of the camera, and does not change or compress anything. This is unlike a JPEG file, which can be considered the end product after the digital camera itself applies white balance, contrast, saturation changes, and compression which reduces the quality of the image.
The advantages of shooting pictures with JPEG mode are:
- The files are smaller, and you can therefore save more to your memory card.
- The image quality of a JPEG file is in many instances acceptable for most uses.
- Often, photographers simply don’t have the time to post-edit their photos, and the cameras ability to do it for them is convenient.
- Many low end cameras are unable to save RAW files, and you can expect to pay more for a camera that is capable of RAW mode.
The advantages of shooting pictures with RAW mode are:
- RAW files contain all the information about that shot, exactly what was recorded in the imaging sensor meaning the highest image quality is preserved.
- With RAW files, you can manipulate your own white balance, color temperature, contrast, saturation etc
- Lossless, editing a RAW file will not reduce the quality of the image.
In conclusion, both RAW and JPEG formats have advantages and disadvantages. It is ultimately up to the photographer to decide what he needs, but without doubt, if you are looking for the highest possible quality and manipulation ability, shoot RAW.
