Why Shoot Raw?

Before I start this post I’d first like to say that one of the reasons I started MrFindlayPhoto is to help answer questions for friends who are still trying to get their heads around photography and their Micro 4/3rds cameras. 

JPEG and RAW files are often confusing for newcomers as it takes an experienced eye to appreciate the differences in image quality that these file types produce.  For the purposes of this post I’ll attempt to simplify my explanation to make it as easy to follow as possible.

What is a Raw file?

In simple terms a camera Raw file is effectively a ‘digital negative,’ which has not been processed by the camera.  Instead of your camera processing the Raw file you take charge of the processing yourself.  The standard image file that your camera outputs is a JPEG that has been processed and compressed and is ready for viewing and sharing.  You can set your camera to shoot both JPEG and RAW simultaneously although this will take up more space on your memory card.  I would recommend doing this as it gives you a good JPEG and Raw comparison so you can see how you've improved on the cameras JPEG output.

Unlike a Raw file a JPEG is not a lossless format and image degradation can occur when it’s generated.  This is not always noticeable especially if your camera gives you the option to record a high quality JPEG (low compression).

Regular photo viewing software like Windows Photo Viewer will not be able to display Raw files.  The software that’s bundled with your camera will allow you to open, view and process Raw files as well as third party photo editing software like Photoshop Elements.

Raw processing can be seen as non-destructive because your Raw file is always retained. Once you've processed a Raw file you will save it as a JPEG or TIFF, which creates a separate file for viewing or printing. This means that at any point in time you can go back to your original Raw file and make changes and save multiple versions of it.

So why shoot Raw?

There are many errors that one can make when taking a photo and although they all can't be fixed, some can without too much fuss.  Exposure and white balance errors are common for newcomers and this can be frustrating if you don’t know how to fix them.  If you make it a habit to shoot a Raw file along with your JPEG then help is at hand.  Of course, I’d always recommend learning how to avoid errors in the first place but that’s another topic of discussion.  Furthermore, your Raw file doesn't only allow you to correct errors but also enables you to make exposure, tonal and colour adjustments to simply improve on your image. 

I've had the flu at the time of preparing this article and have been in bed for a few days so I apologise for the rather mundane photo.  

I took the photo shown below out of my bedroom window purely for the purposes of explaining 'why shoot Raw'.  The photo has been over-exposed by +1.0 (EV) and as you can see the clouds have partly been blown out to pure white with the rest of the image looking ‘washed out.’  The sun was behind the houses leaving them in the shade.  I recorded both a JPEG and Raw file simultaneously using my Panasonic G2 camera.

Original out of camera JPEG

Below is the same out of camera JPEG image that I've processed using Photoshop Elements 11.  I was unable to recover missing detail from the clouds because it’s been processed out by the camera's JPEG engine and no longer exists.  You can't recover detail that wasn't recorded. 

Processed out of camera JPEG

Now let’s have a look at the raw file that’s been opened in Adobe Camera Raw (ACR) using Photoshop Elements 11.  The first screen capture shows the unprocessed Raw image whilst the second screen capture shows the processed Raw image.  Take note of my adjustments in the editing palette and also the differences in the shape of the histogram.  I’ve pulled back the exposure by –0.80 (EV).

Raw image opened in ACR  - before processing

Raw image opened in ACR - after processing

The detail in the clouds that had been lost in the out of camera JPEG image still exists in the Raw image and can be recovered.  This demonstrates that the Raw image is capturing more detail than the JPEG.

Below is the final image that has been processed from Raw and converted into a JPEG.  There's an improvement in the overall exposure and the blown highlights in the clouds have been recovered.  There is a slight magenta colour cast that I haven't corrected but having the Raw file means I can do that whenever I want to. 

Raw converted to JPEG

Now let's look again at the out of camera JPEG image that I processed using Photoshop Elements 11.  As you can see there's an overall difference in the look of the image with the most obvious being the over-exposed clouds.  

Processed out of camera JPEG 

Despite the out of camera JPEG image looking the sharper of the two, you’ll be surprised to find on closer inspection that it contains less detail than the Raw converted to JPEG image. The fine detail in the out of camera JPEG image could be described as fuzzy.  Put simply, you can’t sharpen detail that doesn't exist. 

Here are two side-by-side 100% crops of the image, which shows the difference.  As you can see, the Raw converted to JPEG image has retained more detail in the tree and the chimney than the out of camera JPEG. The difference may be subtle but it's there.

Click image for larger view:

Reasons to shoot Raw

A Raw image can capture more information than a JPEG image.

Blown highlights and blocked shadows can often be recovered.

Exposure errors and white balance can be corrected.

A good balance of noise reduction and image sharpening can be applied while keeping a natural look.

Colour and contrast adjustments can be made effectively.

When processing a Raw image using Olympus Viewer 2 software it gives you access to Art Filters and other effects that can be applied at the touch of a button.  Other camera companies proprietary software also often gives you access to special features when processing Raw images.

Image Quality

High contrast scenes (e.g. bright sky plus shade) often has to be corrected in Raw processing because the camera cannot record all of the tonal information in one exposure.  Some extremely high contrast scenes cannot be corrected in Raw processing and this can be seen as a limitation of the camera and not necessarily the software (assuming exposed carefully in the first instance).  This is partly what people mean when they describe a particular camera as having better image quality than another.  It means one camera will have better exposure latitude (dynamic range) and less visible noise (coloured speckles) at equivalent ISOs when compared side by side.  However, the differences between cameras are not likely to be noticeable at low ISOs and when photographing scenes of low to average contrast.

Well there you have it.  A brief explanation of how shooting Raw can produce better looking photos.  Start experimenting now and see if you can do better than your out of camera JPEG images.

EV = Exposure Value, denotes all combinations of a camera's shutter speed and relative aperture that give the same exposure.  Commonly referred to as a stop (as in f-stop).