When you take a picture in JPEG mode, the camera’s processor takes the raw data captured by the sensor and adjusts the colour, contrast, sharpness and other parameters to produce a finished picture that should be good enough to print directly out of the camera.
When you shoot in Raw mode the camera does none of these things, leaving the user to make these judgements for themselves afterwards, on the PC.
Many cameras now offer the ability to go beyond straight jpeg processing to offer a range of enhancements you’d otherwise have to do in something like Photoshop.
Enhanced images are saved onto the card as copies so you still have the original shot preserved as well. These are some of the main effects:
In camera editing: Redeye correction
The Redeye Reduction flash mode is worse than useless and should avoided.
A much better option is to correct redeye afterwards, and many cameras now offer this in the processing menu. Redeye correction automatically replaces the red areas of your subject’s eyes with black.
In camera editing: D-Lighting/Dynamic range optimisation
As well as being able to brighten shadow areas or darken highlights in an image before you shoot it you can also do it afterwards on some cameras, if you see when you review your shot that you have lost shadow or highlight detail. Many cameras offer varying degrees of correction.
In camera editing: Crop, straighten, resize
The ability to crop out unwanted areas of a shot and perhaps correct a wonky horizon can be very useful if you want to print direct from the media card. Some cameras can also produce a smaller copy of your original, suitable for emailing or posting directly onto social media websites.
In camera editing: Perspective and distortion control
Some cameras offer the ability to correct the effect of converging verticals, caused when you tilt a camera upwards at a tall building, for example.
In some cases it’s also possible to correct other forms of distortion such as barrelling – an effect common with wideangles that causes straight lines in an image to bow outwards.
In camera editing: Beauty mode
Given various names on different cameras, this mode softens skin tones to hide wrinkles, spots and blemishes, and make skin softer and smoother looking.
In camera editing: Colour effects
Most cameras offer the ability to shoot in black and white. Although it’s usually best to shoot in colour and do your conversions on the PC later, mono mode can be useful if you want the effect straight out of the camera for printing.
But if you have a mono post-processing option you can shoot in colour and then create a black and white version in-camera, while preserving the colour original. You may also have a choice of mono effects such as sepia or cyanotype.
In camera editing: Raw processing
Some cameras allow in-camera processing of Raw images. Many enthusiasts prefer Raw files because of the superior quality they can produce, but they don’t look good in their pure state and often can’t be viewed on third-party products.
You could shoot every picture as both raw and jpeg but this uses more space on the card. The option to just process individual raw images, in camera, as you need them, can be very useful.