Today, I’d like to discuss the difference between JPEG and RAW formats to hopefully shed some light and clear up some misconceptions about the topic. Seems like everyone has their own strong opinion about this subject – including myself. I’d like to break up this topic into 3 different posts: the technical aspect of it, Pros & Cons of each, and then a visual comparison. Finally, I’ll close with my personal take on the matter.
Technical Basics –
First let’s look at the technical part, see what the main differences are between JPEG and RAW and apply some definitions:
A JPEG is an acronym for “Joint Photographic Experts Group.” JPG is a common file format that uses a lossy compression method. In other words, when a JPEG is created/saved, it uses 10:1 compression. (Every time a .jpg file is opened and saved over – NOT simply opened & closed, but opened and re-saved and overwritten, it loses 7% of its image quality. So if you have JPEG photos on your computer from 5-10 years ago that look pixilated, that is probably why.) A JPEG is an image that is already processed. When the camera takes a JPEG image, all the processing (color saturation, sharpness, contrast, etc.) already happens in the camera. The images (when exposed correctly) have a small dynamic range, high in contrast and sharp.
One way to think of it is, a JPEG is an image that is already “developed” – kind of like a Polaroid. This processing cannot be undone. So, for example, if the image is overexposed, there is no undoing it. Even if you take it into an image-editing program, you will be limited in the changes you will be able to make to that image.
A high-quality JPEG can be anywhere between 6 and 10 MB.
RAW (.cr2, .crw, .nef, .dng, .3fr, etc.)
Raw is a pretty unusual term to use since the common meaning pertains to uncooked food – but it really is quite a good play on words in this case because a RAW image file is akin to a negative, an undeveloped image – i.e. it’s uncooked. As I stated before, a JPEG is an already developed – i.e. cooked – image. Whereas RAW is not. Now you might be thinking, “well sheesh, why would I want an uncooked image, JPG must be better!” Don’t jump to conclusions just yet… 😉
When the camera takes a RAW file image, all the details aren’t processed in any way when it is saved onto the memory card – it is considered as a Digital Negative, which will be brought into an image-editing program later. This means that if you under/over-exposed by 1 stop, you can very well edit this later. Also, RAW files are both lossless and uncompressed, so their file size is significantly larger than a JPEG. RAWs also come with an XMP sidecar that contains all the image data and tells the RAW file how to look and act. The images (when exposed correctly) are typically higher in dynamic range, low in contrast (have a washed out look) and not as sharp – this is because it’s intended to be edited after shooting.
A RAW file can be anywhere between 8MB and 120MB, depending on what kind of camera it is, and if its 35mm or medium format.
As with every argument/debate, there are 2 sides to consider. A RAW shooter will probably argue: “shooting in jpeg means you aren’t a professional, especially since professional DSLRS have RAW capability.” Another argument they might pose is: “RAW gives you more information to work with than a JPEG does, so why wouldn’t you want that additional information?? Plus it gives you more ability to be creative with your shooting if you know you can manipulate the image later.” Whereas, a JPG shooter will probably argue: “If you get the exposure correct, then you don’t need to shoot RAW!” – the problem with that argument is that it simply isn’t accurate. An 8-bit .jpg file cannot always capture the right exposure. Another argument you might hear is, “RAW is just for lazy photographers who don’t want to bother learning about exposure.” (I have to insert my personal comment here because as a member of Team RAW, I want to clarify that a RAW shooter is anything but lazy because they MUST take that extra step and process and edit their images – a RAW image file is not deliverable to a client.)
There are more in-depth differences between JPEG and RAW files, but I just wanted to cover the basic differences. In the near future Shawn will write about those additional differences and really get deeper into it. Next post I will chart the pros and cons of both RAW and JPG… Stay tuned!