Comparing JPEG (.jpg), TIFF (.tif) and Raw (.nef) File Formats
The Nikon Coolpix 5700--like many digital cameras--offers the ability to save photos in several different file formats. The JPEG file format (with a .jpg file extension) is the most common format; also available is TIFF (.tif) and raw (.nef). Each offer different benefits and drawbacks, including lossy (.jpg) and lossless compression (.tif, .nef), and fast (.jpg) and slow write times (.tif, .nef), to name just two examples.
The point of this article is not to tell you which file format is "best"; to some extent, this is a subjective decision. Instead, I'm comparing the formats to show the differences, similarities, benefits and drawbacks of each format, particularly considering the final result.
I'm using a Nikon Coolpix 5700 for this experiment, but many cameras offer at least .jpg and Raw file formats.
Getting Predictable Results
As I alluded to in my Nikon Coolpix 5700 Review, I usually shoot with Image Adjustment set to 0. Similarly, I leave Saturation set to 0 and Sharpness set to Normal. If I do change them, I always change to +n or -n values--never Auto.
Setting Image Adjustment, Saturation and Sharpness at Auto is kind of like saying "surprise me!" You'll never see the exact same results twice because the camera evaluates and re-evaluates the image constantly. How can you get the desired results if you don't know what the camera will do to your image?
With that in mind, Image Adjustment and Saturation for this comaprison were set to 0. Also in the name of consistency I've manually white balanced these photos. Sharpening was set to Normal. Each image was shot on a tripod at f5.5 for 2 seconds at ISO 100. And, of course, they were shot at the camera's 5 megapixel resolution.
These images haven't received any post-processing. The JPEG and TIFF files are the 8-bit images that come right out of the camera. The Raw file, however, is something special. Ok, I admit it--now that I've sucked you in I want to point out how cool the Raw format is. The more I work with Raw files, the more I see what advantages they have. The Raw file has been processed with Adobe Camera Raw (part of Adobe Photoshop CS [and now Photoshop Elements]), taking the original 12-bit file, processing as a 16-bit file in the Adobe RGB color space, then converted to the sRGB color space and an 8-bit file for the below web-friendly crops.
First, just an overview shot. The Raw (.nef) file should jump out as being very different: it's a little warmer than the JPEG or TIFF, and the brown of the sleigh is substantially lighter. It looks like it might be overexposed a bit, but it's not. In fact, it looks a lot more like the real Santa and sleigh than the other two photos do. The TIFF and JPEG are very similar, though the TIFF is just a titch lighter. In such a little shot, though, you can't make out much detail.
Several sets of 100% crops are below. The first image is the .jpg, the second is the .tif, and the third image is the Raw .nef.
Studying the 100% crops, it's difficult to see much difference between the JPEG and TIFF formats. Careful measuring with the eyedropper tool shows that the TIFF has slightly more shadow detail--a variation of about +/- 0.5 RGB values, for a total variance of about 1 RGB value--but not enough to make any sort of difference.
As I mentioned earlier, at first the Raw crop looks like it must be overexposed because of how light it is compared to the other two--but it's not. The Raw is a much more accurate representation of what the Santa and sleigh decoration looks like. What you're seeing is the benefit of the extra 4 bits of information (remember, the .tif and .jpg started life as 8-bit color depth files, while the Raw .nef starts as a 12-bit color depth file). It's this simple: more bits = more shadow detail.
If you'd like to check my results for yourself, you're welcome to download the original files I used for the test.
- The JPEG is 1.6 MB.
- The TIFF is 14.4 MB.
- The Raw .nef is 7.7 MB
- Lastly, a 16-bit TIFF in the Adobe RGB color space, created from the Raw .nef is 29 MB.
The Raw .nef format gives a lot more shadow detail than either of the other two. Working with Raw files isn't such a big deal, especially once you get a good workflow going; I recommend the book Real World Adobe Camera Raw with Adobe Photoshop CS. The more I use the Raw format, the more I like it; I shoot with it as much as possible. That said, the long write times of a Raw file are a problem sometimes, so I turn to the JPEG format, which works well for many things.
But the TIFF format... I can't see any advantage to shooting in that.