Having covered using Custom White Balance in the first part of this series I'm now going to move on to something that can negate the need for Custom White Balance when shooting available light images underwater.
RAW is a format of image produced by many cameras that includes much more information than is in a JPEG. When a camera takes an image, if it is set to take JPEGs it will immediately do a basic edit of the image and compress it to JPEG form. This basic edit does some sharpening and usually gives some vibrance and warmth to the colours. When shooting in RAW the camera leaves all the original information taken in by the sensor within the file.
What this means is that initially you get a much bigger file than a JPEG, but it gives you much more data to play with. Using RAW format allows you to recover a great deal more from your images than can be done with a JPEG. This includes allowing more colour correction than can normally be achieved and also recovering images or parts of images that have been under or over exposed.
It also means that images initially look flat and less vibrant than a JPEG and you will have to edit your images with software such as Adobe Lightroom. In addition RAW file formats are specific to camera types so when you have a new model camera you may need up to date editing software to even view them let alone edit. If you want to share your images on Facebook for example you will also have to export them as JPEGs after editing.
You need to also take into account the increase in size when looking at memory cards and hard drive space.
So here are some examples of the difference shooting in RAW can make.
Below is a shot taken using available light as it came out of the camera.
And here it is after being colour corrected using Adobe Lightroom.
Here is another shot, this time under-exposed.
And now after a couple of minutes worth of editing.
The same is true of images with over exposed sections, such as this shot of the Lovell Telescope at Jodrell Bank.
Here is the same image after a minute's worth of adjustment in Adobe Lightroom
Here are some cropped images to show the difference better.
So shooting RAW is clearly a big advantage, especially in underwater photography where lighting conditions are often difficult to control and can change quickly.
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Alphamarine Photography runs photo editing workshops through dive centres in the UK. If you'd like to attend one of our workshops check our Events page for dates and locations. If you own or work with a dive centre or dive club and would like to host a workshop email us at firstname.lastname@example.org You can also contact us through our Facebook page Alphamarine Photography Ltd
Coming Next: Part 3 Being able to use a wide angle lens.