Exercise: Raw

The purpose of this exercise is to demonstrate the advantages of raw, but at the same time to put these advantages in perspective. Higher image quality from raw is often over-praised. I set my camera to the combination of raw plus the highest quality JPEG, meaning that each shot will be saved twice, once in raw and also camera-processed as a JPEG.

In theory, JPEG compression can introduce artefacts, particularly if it later receives strong adjustments in post-processing. In practice, with what I will do in this exercise, there will be no noticeable loss of quality. I planned to shoot 3 images, in 3 different lighting situations, one daylight, one artificial light and one with a high dynamic range.

I planed to use Lightroom 3 to process both the JPEG and the raw files.

The next part of the exercise was to compare the 2 versions of each scene, paying special attention to:

• dynamic range
• white balance and colour
• local adjustment of any kind





The quality of the images really appear very similar initially and on 100% zoom with no real difference in the dynamic range. The only real obvious difference being the raw image is a little lighter in colour. I like the option of being able to change the white balance, which I did with this image changing it to 'daylight', I normally quite like 'shade' but this made the image look too yellow. I also changed the exposure, contrast and saturation but only by a fraction.

This is my 'artificial light' image, its taken under halogen lighting with some tungsten behind.
The top image is the JPEG and the image below the raw, the difference in the white balance is easier to see in the flower petals with the raw file appearing lighter. The dynamic range looks the same in both the images.

 

Again in these two dynamic range images, the top image being JPEG and the bottom a raw image, the first difference is in the colour, the raw image is again lighter with the white balance cooler in the raw image, the difference looks similar to a daylight and shade white balance. The difference in the dynamic range at 100% magnification is similar, I was looking for artefacts in the JPEG when zoomed in but didn't see any.