DSLR Guide 8 - RAW
 
The DSLR Guide returns with the lowdown on shooting in RAW.  Why is it good?  What’s bad about it? and Should you be using it?
 
As always, have your manual at the ready so you can find out how to access the RAW settings on your camera.
 
As you may have noticed when you set up your camera, you have a choice of file formats in which to save your images.  For most cameras, it’s a choice of JPEG or RAW (some allow you to shoot both at the same time).  But what effect does that have on your photos?  First of all, lets look at the two file formats.
 
JPEG
JPEG is an extremely common file format which was established as a standard in 1992.  Consequently it’s compatible with a wide range of applications from Word to Photoshop.  It’s also an internet standard, so if you put a JPEG on the web, everyone will be able to see it.
The idea of JPEG is to store photos in a small file size, but to be able to do that it has to ‘compress’ the image.  Think of it like screwing a piece of paper into a ball*.  If you screw it up, it takes up less space, but if you try to flatten it out again it’ll have creases all over it.  JPEG compression has similar consequences for your photos.  Your camera will offer you several different compression options (how tightly do you want that ball of paper screwed up?)
 
Have a close look at these two pictures.  On the left is an image saved at the maximum JPEG quality; on the right, it’s saved at the lowest quality.   See how areas of the low quality image seem ‘blocky’?  That’s JPEG compression at work.  Even at the highest quality, the compression ‘artifacts’ (that’s ‘blocky bits’ to you and me) are visible.
 
Maximum JPEG Quality                                          Lowest JPEG Quality
 
 
RAW
RAW is the generic name for an unprocessed camera data file.  RAW files take every single bit of information your camera captures and leaves all the data intact and uncompressed.  This means you get a wider and smoother range of both colour and brightness.  Because none of the information has been lost, finer adjustments are available in post-processing.
 
The example below is as near as I can get to showing you what a RAW file looks like close up, bearing in mind it has to be converted to a compressed format to get it on the web.  You’ll notice that it looks more dull and ‘flat’ than the JPEG.  That’s because it’s not had any enhancements done to it at this point - it’s exactly as the camera captured it.  
 
RAW image
 
 
JPEG Pros & Cons
Now you know what each file format does, lets look at the pros and cons of the two formats, starting with JPEG.
 
Here are the pros...
  1.   JPEGs take up less memory, so you’ll be able to take more pictures on your card.
  2.   Because they take less time to write to the card, you can shoot more images in succession.
  3. The JPEG format can be opened in pretty much any application which accepts images (and can be printed directly from the card)
  4.    You can customise the image processing options within the camera (sharpening, colour etc)
  5.    This means you have less to do when you get them to your photo editing software.
 
And now the cons...
  1. You lose a lot of quality if you have to change the exposure or white balance because you got it wrong in-camera.
  2. Any image editing you do after capture means you’re essentially editing the file twice (once in-camera, once on the computer).
  3. JPEGs compression means you lose image quality.  This is especially obvious if you make adjustments in post-processing.
 
 
RAW Pros & Cons
So how does RAW compete with such a popular  format?
 
The pros...
  1. Every smidgen of data is recorded and kept intact.  This offers the ability to make adjustments with the least possible loss of quality.
  2. Image enhancement is dead easy - most software allows you to make adjustments using a slider or drop-down menu to change everything from white balance to highlight recovery.
  3. Fine detail and full range of tones are preserved.
 
And the cons...
  1. You’ll spend more time post-processing your files on the computer, although it’s all in the name of quality photos.
  2. RAW files will take up more space on your hard drive.
  3. You need appropriate software to process RAW files.  Fairly basic RAW conversion software comes with most DSLRs.  Photoshop CS and Photoshop Elements 3 onwards also have RAW conversion tools, or you can go for one of the new RAW workflow packages which combine cataloguing with slick RAW conversion software.
  4. You’ll have to process the files and save them as JPEGs if you want to get prints from the high street labs.
 
 
I know what you’re thinking
‘So shooting RAW means more work for me - why would I want to do that?’  Right?  
 
Let me show you some examples of just how much difference shooting in RAW can make.
 
Recovering shadows/preserving highlights
The first image is the RAW file straight from the camera.  The trees are underexposed - if I’d let any more light into the camera it would have blown out the highlights in the background.  The image above is the adjusted RAW image.  The detail from the shadows has been recovered yet the background detail is also still there.  The image to the right is a JPEG version and you can see that the editing has caused a loss of detail in the background.  It’s also very obvious (on closer inspection) that it’s been edited.
 
White Balance
    
This was the worst example I could find!  One drag of the white balance slider and it’s all sorted out.  You might be able to correct this degree of colour cast in a JPEG image but you’d lose so much quality in the process that it would hardly be worth it... and it would take a lot longer.
 
For the record, I did take another shot afterwards with the correct white balance, but it’s nice to know I could correct it with my RAW tools if I’d needed to.
 
 
What RAW can’t correct
Shooting in RAW isn’t a cure-all.  It can only do so much.  It can’t cure camera shake; it can’t make a badly-focused become sharp; it can’t put back data which was not recorded.  Get the settings right in-camera and RAW becomes your best friend... and when things don’t go according to plan, RAW is a lifesaver!
 
 
So should I be using it?
That’s a question I can’t really answer for you.  For many people, the file sizes alone will put them off RAW and that’s a valid concern, as is the cost of additional software if you don’t have it already.  You’re also perfectly entitled to stick with JPEG if you want nice-looking results straight out of the camera.  But, if you want full control and full quality from your photos, plus a level of image processing which can potentially save your skin, give RAW a try.
 
 
* Kudos to Gary for the paper crumpling analogy!
 
Thursday, 14 December 2006
Techniques, tips and tricks to help you take better pictures.