Most digital cameras offer a choice of image capture in both JPEG and Raw formats - so which is better?
Which should you use - and why?
Well, let's start off by explaining the terms JPEG and Raw.
JPEG (Joint Photographic Experts Group) is a standard digital file format that can be 'read' by any computer and written by nearly all digital cameras. It's the format of choice for photos displayed on the web and most High Street photo labs prefer (or insist that) your photos are written to disk in JPEG format because it suits their workflow.
I'm not going to go into a lot of detail about how JPEG works, if you really want to know the technicalities there are specialist websites for this, I'm just going to explain what JPEG is, what it does, and its advantages and disadvantages...
JPEGS
Jpeg is a compressed file format, that is, it's a format that takes up less space than most others, which means that a large number of images can be stored on a memory card or a hard drive.
It can also be 'programmed' by the camera to record the images in a certain way - for example with more or less colour saturation, with more or less sharpness or more or less compression. This makes it an ideal choice for many types of photos because, although any image can be manipulated once it has been transferred to the computer, the sharpness, colour saturation etc of shots recorded as JPEG files can be set before the shot is taken, which means that far less image processing is needed later. In fact, relatively little image processing can be carried out later (without substantial quality loss) because the camera has 'decided' which information needed to be retained and which can be discarded. Sometimes this 'decision process' works very well but sometimes the baby is thrown out along with the bathwater!
Most cameras allow JPEGs to be captured at various quality settings. Different manufacturers use different terminology, but basically what they offer is a range of different compression settings, and, sometimes, different quantities of pixels. The higher the compression, the smaller the file and therefore the less space it will take up on card or disk. That sounds good, but when files are compressed the quality suffers, so it usually makes sense, if shooting in JPEG mode, to use high quality settings whenever possible.
Many digital cameras also allow images to be capured in Raw Mode. Unlike JPEG and most other digital file formats, raw is not a proprietory file format that can be read by any imaging software programme. In fact, with a few exceptions such as Photoshop CS and Capture One, it can only be read by specialised software supplied by the camera manufacturerer. Camera manufacturers normally include raw conversion software with their cameras but the complexity and usefulness of the software can vary a lot, and sometimes it seems to do nothing more than open the file, allowing no image enhancement at all.
But if you have sophisticated software, shooting in Raw mode will allow you to manipulate the image to your heart's content, and to end up with very high quality images.
Basically, a Raw image is the digital equivalent of a negative. All the information recorded by the camera is there, and the photographer can change just about any of the settings - colour temperature, hue, contrast, saturation, exposure and so on without losing any of the information contained in the file. Once the required adjustments have been made the file can be 'saved as' (JPEG, PSD, TIFF or whatever) leaving the original raw file in its original form.
Adjustments to basic settings are very easy to carry out on raw files. The image below is a screenshot of a raw image displayed in Photoshop CS. All the basic information is shown - Camera make, lens used, f No. and shutter speed at the top. At the bottom you can see the file settings - Adobe RGB, 16 bits per channel, image size (6144 x 4111 pixels)
Top right, you can see a histogram, which gives colour and exposure information.
Don't worry about the detail, it's a bit too small to see. Here's an enlarged version.
You can see that the histogram doesn't include much shadow or highlight detail and the colour temperature, at 5,500K, is way out.
Now take a look at the screenshot below, all I've done is to adjust the colour temperature and the brightness and shadow settings, all that was needed in the way of basic adjustments on this image. The 'Tint' slider changed automatically with the adjustment to colour temperature and the histogram now shows a wider range.
The close-ups above show severe JPEG artifacts, this was caused by having to enlarge the JPEG files of the screenshots. It happened because the image contains too little information, and is a common problem with JPEG images that have been over-sharpened or enlarged.
And this is the image, with the adjustments carried out.
So that's the main difference between shooting in JPEG and raw - but what are the advantgages and disadvantages?
JPEG advantages
Small file sizes
Rapid writing to disk
Minimal image processing needed
Reduced time transfering files from camera to computer
Disadvantages
Files contain far less information (8 bit, as opposed to 36 bit, 42 bit or 48bit for raw files)
Settings are determined largely at the time of shooting (can be changed later but there will be substantial quality loss)
File compression reduces quality (lossy file format)
Raw advantages
Files contain all of the information captured by the camera, normally resulting in much higher quality
'Digital negative' can be kept for future manipulation (changes are saved into a different file format)
Raw disadvantages
Files are larger and need more storage space
Image processing takes far longer and needs both a fast computer and specialised software
Some digital cameras offer an alternative to raw or JPEG image capture - TIFF.
(Tagged Image File Format) is a lossless file format, i.e. there is no file compression and therefore no quality loss because of file compression. It's a very useful file format for use on the computer (more about this below) but frankly it's less useful for actual camera use - the files are large and slow to write and although the quality is higher than with JPEGS TIFF file formats don't offer any real image manipulation advantages over JPEG files.
I keep mentioning the difference in file sizes, but what do these differences amount to in practical terms?
Well, this depends on the camera, but here are the figures for my Fuji S2 Pro, which can write in 2 different JPEG qualities, Raw and Tiff. The figures will be diffferent with different camera models.
1. Tiff - 28 images per Mb card space
2. Raw - 72 images per Mb card space
3. High quality Jpeg - 211 images per Mb card space*
4. Low quality Jpeg - 449 images per Mb card space*
*This is just an estimate. Actual file sizes vary according to the content - files containing a lot of black are larger than those containing a lot of white
I mentioned earlier that once raw images have been opened they can be saved into a different file format. The normal choice will often be between TIFF and JPEG, and if saving in JPEG format the compression value can be set to suit your own quality needs. My personal choice is to save in TIFF, except that I also create backup files in JPEG, with the expectation that they will (hopefully) never be needed.
The reason for this is that although there is no further quality loss when opening, closing or copying JPEG files, there is a further quality loss whenever JPEG files are saved. Because of this it makes sense to save copies of raw files in TIFF format, at least until all required image manipulations have been completed, and to save files captured in the camera in JPEG format to TIFFS too, as soon as they are transferred to your computer.
O.K., I hope I've explained, in this very basic article, the advantages and disadvantages of JPEG and Raw camera files - but which should you use?
Well, it all depends on your type of photography, the quality produced by your camera, the final purpose of the photograph, the processing speed of your computer and the amount of storage space available. Let's try some examples...
1. Family photos taken in good lighting conditions. I would use JPEGS, because:
Top quality, big enlargements will probably not be needed
The camera (or the photographer) should be able to get the exposure more or less right in camera
The contrast range will be 'normal' and very little image manipulation will be needed
There is no need to spend a lot of computer time converting images taken in Raw format
2. Family photos taken indoors using normal household lighting
Raw format would be better because colour corrections can be made easily and accurately, and
under/over exposure can also be corrected
3. High quality studio still life shots. I would use raw because
Top quality is essential
Manufactured items show up the faults created by JPEG file compression far more than natural, irregular shapes
Very few shots would normally be taken in a day, so the extra processing time needed for raw files doesn't really matter
All necessary computer adjustments can be made easily and without quality loss
Differently-adjusted raw files can be combined if required
4. A wedding, with both outdoor and indoor shots - I would normally use raw for shots during the ceremony, taken with natural or with existing tungsten lighting, to allow easy colour correction. I would also use raw for outdoor shots, especially in bright sunny weather, because raw can cope with high contrast much better than JPEG. However, I would normally use JPEG for almost all of the other wedding shots, especially those taken in dull weather or at the reception.
Hope this helps.
To learn more about all aspects of photography check out what Photolearn can offer you.
Return to the Help Centre
Jpeg or RAW
