To take a close look at the difference between shooting in RAW and shooting in JPEG format, this exercise required me to shoot three different scenes in both RAW and JPEG. The scene set up would be as follows:
- One daylight image
- One artificial light image
- One high dynamic range
For each of these exposures I made sure my settings were correct for the white balance (i.e. daylight, fluorescent and cloudy) as that is one of the things that is stripped out of the final processing abilities for JPEG. I also tried not to under or overexpose any areas for the benefit of trying to make the images react similarly to post-production editing. Of course the idea of shooting the high dynamic range image was to show clearly how the two file types react under manipulation.
This would enable to import both images in to my editor to take a look at what the differences are. I would look at the images without any enhancement first and then with enhancement to see how they stood up to manipulation. I expected the JPEG images to start showing artifacts much sooner than the RAW files, especially in the shadows.
The first thing to note about the two file types is the file size. My camera generally gives me a RAW file size of around 15Mb. The JPEGs normally come in at around 4.5Mb. Instantly I can see that there is more information contained in the RAW file than the JPEG (around three times the file size). This is because the JPEG is processed in camera from the RAW information and gives a result that is pre-designated by the camera’s software algorithms. So straightaway all the other information that I might want to use in post-production is stripped away. It still leaves a very good image but one that I would ultimately expect to have less control over.
So after opening them in Aperture (which natively handles both RAW and JPEG files) I can inspect the images side-by-side and give my initial reaction to how they look before I edit them at all.
The first thing that is apparent is the difference in shadow detail on all the images. The RAW file has way more detail in the darker areas of the image. Nowhere is this truer than in the high dynamic range image. I have exposed for the sky to accentuate the blue and also to cast a large shadow in to the tower on the left. The JPEG holds up well in the other areas of the photograph (because that’s what I have exposed for) but has large areas of dark shadow. Surprisingly though, when I turn on hot/cold spots to see where the areas of absolute black are, there isn’t that much difference between the two images. It would just appear the the JPEG is more under exposed in general in that area of the photo, giving the impression that it has more absolute black spots. There is also a tiny amount of overexposure in the clouds on the RAW format, which doesn’t appear on the JPEG. When I start to use the adjustments (black point) to get rid of this black the difference is notable. The RAW file deals with it easily, leaving a nicely contrasted image with detail in the shadow. The JPEG on the other hand is very flat and has no great detail in the shadow. The image is fine as it stands alone, but not when compared to the RAW image.
When I look at the images shot in artificial light, there is not much discernible difference at first. The colour cast is similar on both (having shot for fluorescent light) and the areas of high and low light are very similar although again there more detail in the RAW file in the high and low light areas. The noise in both is fairly even (having shot at ISO 3200). Now, when I start to use some global adjustment on the images the differences become apparent. The black areas of the RAW file disappear very quickly with good detail left behind whilst those on the JPEG image do not. However, the same is not true of the highlight areas. In the JPEG image the highlights disappear very quickly with the application of the recovery tool. In the RAW file I have to use the full extent of this tool to remove the red highlight warning. This is because in the camera software has already taken care of these highlights to some extent when processing. However, on inspection with the loupe tool I can see much more detail in that highlight area after working on it on the RAW file than I can on the JPEG. When applying sharpening to these images, at the extreme end, the JPEG starts to lose detail and become overly contrasted (the sharpening tool boosts contrast locally to image edges to make it appear sharper to the eye) whereas the RAW file holds the detail very well, especially in the noisy conditions.
The major noticeable difference between the two images happens when I apply the white balance to them. In the image below I have just used the automatic white balance control, which shows two very different results. The RAW file is much more blue, more cool than the JPEG which in turn has also got cooler but not to the same extent as the RAW file. It is a result of me using the fluorescent setting in the camera. The JPEG is now stuck with that setting having stripped out the other possibilities during in-camera processing. The RAW file has more information (all white balance possibilities) at it’s disposal and when I use the automatic white balance in Aperture gives a very different result as the software uses all the information at its disposal to come up with the average white balance. It’s very subjective, but I prefer the JPEG version with slightly more warmth and is a case where I think the JPEG format wins over RAW.
The last two images are shot in daylight and again the difference in highlights and lowlights is very noticeable. This time I concentrated on the lowlights in each image. When working on the RAW image the black areas disappear very quickly with little adjustment, with the JPEG a lot more work is needed to get rid of them. The other noticeable thing using these two images (which is relevant to the lowlight areas) is the amount of instant contrast difference there is between the two file types (without any adjustments). The darker areas of the JPEG conspire to make the image more contrasting and somewhat sharper on first inspection with the loupe. Again this is the camera’s software at work sharpening the image before it leaves the camera. This I find undesirable as I want to have control over the contrast and sharpness and once it leaves the camera in ten JPEG format there is nothing I can do to ‘undo’ that sharpness that has been applied. In some camera models you are able to reduce the sharpening that happens in-camera. I have the ability to change my creative style (i.e. normal/vivid/portrait etc.), which does affect the sharpness/contrast that is output, but I cannot set the parameters for it. This is something worth remembering for future reference.
An interesting exercise as I generally shoot in RAW (although there are times when time is a constraint and I shoot in JPEG to negate the need for so much post-processing), but can see here how my images are affected by shooting in one or the other. I would choose RAW over JPEG every time, but it is interesting to know how to control the output somewhat if I were to have to use JPEG for some reason and indeed that I should shoot differently with it than I would with RAW (which is ultimately much more forgiving).