dinsdag 5 mei 2015

Blog 12: RAW vs JPEG

Blog 12: RAW vs JPEG

RAW and JPEG. Every photographer will have to deal with these file types at some point. But what do they mean, and how do they differ? In this blog, I want to tell you about JPEG and RAW and which one to use when.

The very moment a digital camera takes a photograph, all kinds of processes are activated inside the camera. Every digital camera has a processor (much like those found in computers) that processes your photograph before putting it out on your screen. JPEG files get a lot of processing done by the camera, while RAW files do not. Figure 1 depicts this.  

Figure 1: Sensordata to JPEG or RAW
As can be seen in figure 1, there are quite a few processes between sensor data and the JPEG image file output. The more serious photographers and enthusiastics alike want to manually control these processes in the post process workflow. The problem with JPEG is that you can’t. Settings like saturation, contrast, white balance, noise reduction etc. are all stored and locked inside the JPEG image file. To make matter worse, the image quality of JPEG files is reduced by compression, to minimize file size. The camera uses the build in photo editing software to do this. This software can be tweaked in the camera menu, as shown in figure 2 and 3.  
Figure 2: In-camera settings for JPEG files

Figure 3

 The settings used for JPEG compression are often stored in so called picture styles (figure 3). These picture styles have preprogrammed settings that can be used for several situations. For example, the portrait style will focus on sharpness, the landscape style even more so. These settings can of course be changed to suit your preferences. The monochrome style will make all you JPEG files black and white. As said before, these settings cannot be changed afterwards. A black and white JPEG will always remain black and white.

The RAW file is the complete opposite of the JPEG file format. As can be seen in figure 1, RAW files do not receive any processing in-camera whatsoever. The picture styles have no influence on the RAW file whatsoever. The RAW file only contains raw sensor data. Because the file does not get any processing done, it might look less good then the JPEG when viewed on a computer screen. Why then, would we want to use RAW instead of JPEG? Because a RAW file, containing loads more information than the JPEG, allows us to post process the images in specialized software such as Adobe Photoshop. 

With a RAW file, it is possible to alter white balance, saturation, contrast, noise reduction and many more settings after the photograph has been taken. To illustrate this, I want to use an example of a wedding I shot a few weeks ago. Figure 4 depicts what happens when you open a JPEG file in a program like Photoshop.

Figure 4: JPEG opened in Photoshop CC

As can be seen in figure 4, Photoshop will give me no options whatsoever to alter the settings of my photograph before turning it into an image file. When I made this photograph, I had my camera set to the monochrome picture style, because the bride to be asked me to shoot the make-up and hair session in black and white. Luckily for me, I had my camera set to RAW+JPEG (makes the camera record both).
Figure 5: Same photograph, RAW file

Figure 5 depicts the same photograph, but this time I have opened the RAW file instead of the JPEG.
As can be seen in figure 5, all settings (including black and white), that were locked inside the JPEG, are available for post processing before the data is made into an image file. The sliders on the right side of the photograph visualize settings like white balance, saturation etc. Because of this, I can manually alter these settings, giving me more control over what happens to my photograph!

File size and workflow
The fact that a RAW file contains more data than a JPEG, can also be seen when comparing file size. A JPEG from a 20 MP camera will approximately be 10 MB. A RAW file of the same camera will amount to about 25MB. This means that your memory card will be able to contain less photographs when shooting in RAW. This doubles if you set your camera to RAW+JPEG.

The big question that hunts photographers around the world is this: Do I use RAW or JPEG? Most photographers curse the use of JPEG, because of the loss of control (little control freaks, the lot of us). Still, it can be wise to use JPEG instead of RAW, mainly if you are, for example, in a hurry to post photographs online (think sport events). A great advantage of JPEG is that 99% of the devices we use in daily life (like laptops, smartphones and tablets), are able to open and show JPEG files. If you want to use RAW files, you need a fast computer and special software. Also, because of the file size, it is far easier to share JPEG files then it is to share RAW files. I think it is impossible to answer the question of whether you should use JPEG or RAW. The bottom line, in my opinion, is this:  are you going to edit your photographs using special software and do you not want to carry around extra memory cards? If the answer is no, or if you are in a hurry, use JPEG. If you want the extra control in post processing and want to get the maximum out of your photographs, use RAW.

Or do what I do! I set my camera to RAW+JPEG S, letting my camera record both the RAW file and a low quality JPEG (can be seen in figure 6) and just carry around a few extra memory cards.

Figure 6: RAW+JPEG (low quality)

This way, selecting photographs will be a lot easier and no data can ever be lost. I use the low quality JPEGs to search for editable photographs that I find worthy of putting some time in. It is faster to scroll through JPEG files of 2 MB than to open all the RAW files (25MB a piece). If I find a photograph that is good enough to edit, I open the RAW file and use Photoshop to post process my image.

That is all for this blog! I hope you have all learned something from this post. There are more blog posts on my website http://photojitsu.nl/blogpost.html.  To follow me and my work, you can “like” my Facebook page www.facebook.com/photojitsu or follow me on Twitter @photojitsu_nl .
Until next time!

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