photo by: Aaron
“RAW Vs. JPG”
If you go through the jungle of photography information blogs, you will find a million and a half articles on this subject. You have both parties from the RAW haters to the JPG haters. I know over at Ken Rockwell’s blog , he has created quite a stir by continuously preaching the benefit of JPG and horrible aspects of RAW. I am actually quite impressed with the amount of thought that he has put into his blog and if you have time to process through the pages and pages of text then I encourage you to do so. He has some good info.
While I appreciate Kens stance on the issue, I think his approach and info is outdated. This is not a “kill Ken” post like some others have posted, this is merely my take on the digital age old battle. Before we go on, I am going to make sure we are clear that you understand that I am avidly pro “RAW”. At one point, I developed a workshop (that I may continue to do in the future) called “photon to photoshop”. The goal of the course was to allow people to begin to understand how digital camera works. It allowed people to understand the exact process that a photon went through from when it hit the photosite all the way to the pixel you edit. Understanding that process has allowed me to pick up my camera and know exactly what is going on when I press the shutter button. It was an interesting journey for me to learn this process. It also gave me a different view on this debate. I’m going to take you through a little bit of the RAW process. I want to give you a few technical details on RAW along with debunking a few myths
Now that the formalities are over and my intro is written, I am just going to delve into the nerdy goodness.
The beginning of an image
Digital cameras capture light via a sensor panel. These panels (because of popularity I am talking about the Bayer CFA) are made up of thousands of little sensors called photosites. When light hits a photosite, it is then recorded as a voltage reading for that photosite. That value is then digitally recorded. This record is the base of your digital image. This is the most basic form of data that your camera has about an image.
Decisions, decisions, decisions
This is where the real split begins. Depending on the camera, in a professional DSLR, you can have between roughly 12 and 16 bits of information. That is roughly 4k-16k levels of recorded light. Side note: true 16 bit is not possible in most cameras, the data is just converted to “16 bit”. Most camera’s shoot 14 bit. Without going into the whole other topic of bits per channel and color profiles, I will give you the short version. The more bits you have, the more levels of information you have. It applies to both contrast levels and color levels. When you save your file as a RAW file, all “12-14 bits” is stored. When you shoot in JPG, this image goes to the camera’s processor.
Compress, demosaic, rinse, repeat.
Once that information hits the processor, this is what it goes through.
Once that file hits the processor, it starts an interesting journey. First, your camera takes each photosite and applies a color to it based on the information from the photosites around it. This is called the demosaicing process. This process is done with the camera’s built in firmware. This is usually when chromatic aberration, false color artifacts, aliasing and any zippering is introduced.
Sensors and all the algorithms and logarithms involved are intensely complicated. Because of this I will try to put it in layman terms. The image at this point will appear to vary in natural contrast so a tone curve is applied to the image to correct for this. This is also where gamma correction takes place.
Sharpening is usually applied at this point. People generally have a few options of sharpening. Unfortunately this process can lead to some halo’s or bad tonal control. In low contrast exposure you wont have too many problems but in high contrast situations you can have some major halo’s. Side Note: if shooting RAW and using photoshop, try the “high pass” filter. It has some smooth sharpening.
-Apply the rest of the presets
The camera goes through a process of applying all of your presets. The white balance, noise reduction, contrast, saturation and any other preset is applied.
After the image is “beautified” by the camera, it goes through compressing. This is where it takes the 12-14 bits of info and scales it down to 8 bit. This is where artifacts and other weird things can be introduced. First of all, you are scaled down to 256 levels of information. This is a huge drop. Where some of the tonal data may be kept, a good deal of color data is scaled down from a possible 16k of gradient data to 256 levels. You do get smaller file sizes but at a little bit of a price. Once this happens, you cannot undo it. The JPG is set. There is no getting back the information.
The “RAW” fear.
There is a fear that has been spread by some people that I have to put to a complete halt right now. People tend to think that when you shoot in RAW, you will never be able to open your images on your computer. Fortunately for us RAW shooters, that is very far from the truth. With the increase in popularity of DSLR’s, more and more companies are supporting RAW. It is true that each company has its own RAW file but that isn’t an issue. There are a handful of paid and free image programs that provide RAW codecs. Because I am committed to this statement, I will give you a list of SOME programs that open RAW files.
There is a ton of programs that will open RAW files but chances are, if you have a camera that shoots in RAW, you will also have a disc provided by your manufacturer that opens RAW files.
If you take the time it needs to take, you take less time.
IF you are looking for a photo to post straight to facebook or flickr, then JPG will be easier for you. If you are planning on not doing any editing and sending it straight to the net then I can see the benefit of JPG. The only problem is, is 90% of the shooting I do, I like to edit and do some corrections. I never send a photo off to a client unless I do some form of editing. If you are planning on doing ANY editing at all then JPG will severely limit you. As far as time goes, there is no actual time difference for me when editing the two. I put both RAW and JPG through the same process and both take the same amount of time.
But it takes a lot of space
Another of the popular arguments against RAW is that it takes space. While the file sizes are larger for RAW files, storing those RAW files is very cost effective. I bought a 1TB hard drive for a hundred bucks. This will hold hundreds of thousands of RAW files. Their are some great deals on storage that will be way more than enough space. Because I am a nice guy, I will even give you some links to some
Western Digital WD Elements 2 TB USB 2.0 Desktop External Hard Drive ($99)
SanDisk Cruzer 16 GB Cruzer USB 2.0 Flash Drive ($20)
SANDISK Card, SDHC, 8GB, Class 10, 30MB/Sec 30MB/Sec($54)
Verbatim Acclaim 500 GB USB 2.0 Portable External Hard Drive($71)
There are some opinions out there that RAW and JPG are not actually different in quality. The only people who make this statement are people who don’t know what they are talking about (did I just say that). Because your computer is more powerful than your camera’s processor, the output is cleaner and better than your camera’s output. Because JPG is a set process, you have limited say in the output. When editing to JPG with your computer, you have complete control over every detail. Human interpretation of an image will always be better than machine so for this fact alone, the quality of a image will be higher with human control. When you are viewing a small JPG on a screen you will not be able to see these differences but the moment you make a large print, blown up on a computer or even crop in, you will see a difference. Even in his anti-RAW article, Ken Rockwell states:
“I will admit that on the D70 the differences in default sharpening are such that the raw images do look sharper than the JPGs if you’re looking zoomed in to 100% on a computer, but were still invisible to me in 12 x 18″ prints.”
Basically, he was saying that if he wanted a larger print or wanted to crop into his image, the RAW image would be sharper. Don’t even get me started on dynamic range. JPG may possess the same contrast range that a RAW has but it only has 256 levels of contrast between the extremes. RAW can have up to 16k. This means that your gradients are smoother and your color has more detail within two extreme values. With JPG you lose detail. If you need proof, try to do a tonemapped HDR image with a RAW image and a JPG.
If you would like to see photos of some of the quality difference, there is a neat post here. Keep in mind his photograph is 11×14 with no crop. If you were to crop in or if you were to print off a 20×30, you would see the difference from 5 feet. The worst part about it is you can’t just sharpen your image to get back detail. Because it has already gone through the camera’s demosaicing process, it has already discarded that information.
Saving my RAW
For those of you who don’t know. There is a standard RAW format that will never change. It is called DNG. When I am dealing with a fine art piece I go out of my way to save that image. When I am going to be making good money off of a single image, I will save it as a DNG, NEF, TIFF and JPG. Now, to some this may seem like overkill but I think people like Ansel Adams would be on my side. He worked on Moonrise over Hernandez NM till the day he died. He spend time perfecting that image. Let me put it like this. Would you rather error on the side of “too much information and saved work” or “not enough information and limited possibilities. When I revisit my work, I like to know I have extracted everything.
If the technobabble didn’t convince you, this emotional appeal will.
I understand the myths spread about RAW files. I understand the appeal to not have to edit. Heck, I even understand the desire to “have your photos now”. What I don’t understand is, why you would not want the most out of your photograph? Why would you not want that extra sharpness in larger print? Why would you not want more information to work with to extract every bit of beauty from an image? Why would you choose to be limited in creativity in any way?
In everything that I shoot, I craft. I touch every photo I take, that is what gives me my style. I create an piece of art, not a reproduction. When I was a wee photographer, I took an image of a lighthouse. I took it in JPG. I created a really great image but a few years later, I was working with a really cool editing technique. I realized that that image would be perfect for the style I was using. When I went back to the image, the technique I was using looked like crap because of the lack of light information. Many times, I have wanted to try an HDR or some other editing technique on my old JPG’s and I cant get high quality because the information is just not there.
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