JPEG Photos vs. RAW

When taking underwater digital stills the two most common formats are JPEG and RAW.

JPEG

A JPEG photo is run through an Image Signal Processing (ISP) algorithm. The ISP has several steps to improve the visual look of the image such as de-noising, sharpening, HDR, colour correction, and more. The file is then compressed to make it smaller. JPEG photos are what we are all used to seeing and this is acceptable for greater than 90% of users.

RAW

A RAW image is data straight from the sensor saved to a file, pixel by pixel. It may not immediately look as visually appealing as a JPEG, but this is the format preferred by photographers as they can then run their own processing in Adobe or similar program to apply their own effects rather than using the automatic JPEG processing.

The image on the left is a RAW image straight from a sensor. The image on the right is an edited version of the RAW, with colour corrections applied. The JPEG ISP in a camera, does the same thing but automatically.