The JPEG standard is named after the group which created it – Joint Photographic Experts Group. The JPEG format compresses the data at minimal loss of quality by analysing pixels in blocks 8×8 – i.e. 64 pixels at a time. JPEG compresses the image by following these steps:
- levelling the colours within the block
- setting an average value to the upper left pixel
- recording that a pixel within this block uses three full bytes of data
- assigning to the remaining 63 pixels shortened values depending on how close they are to the average one
- analysing the remaining 63 pixels within the block
- if the pixel is close to the average value, JPEG replaces is with the average colour.
When using the JPEG format there is some loss of information depending on the level of compression, but it remains, nevertheless, the most convenient format for recording files in amateur digital cameras as the loss of quality is negligibly small and practically unnoticeable. This format can save a lot of storage space on the memory card and it is easily and quickly processed and recorded by the camera software, which is important from the point of view of the user.
For example, Sony A7iii has 3 different settings for JPEG image compression rates (*JPEG) – Extra Fine, Fine and Standard, which allows an SD card with 32GB storage space to save up to approximately 2000, 3500 and 5000 photos respectively, each with a 24 mp resolution, depending on the selected compression rate. You should always keep in mind that using compression diminishes quality. In the example below you can see how the quality of a single photo changes when it is saved using 3 different compression rates
.
The TIFF format (Tag Image File Format) is a file format which record images without loss of quality.
Similarly to the JPEG format, TIFF also supports 8-bit images on the grey scale and 24-bit colour images. Unlike JPEG, the TIFF format also supports 1-bit black and white and 8-bit colour images for the various colours. It should be used when saving an image which has to be edited multiple times in order not to lose from the quality of the image with each new save. With the TIFF format the colour rendition is at its fullest.
TIFF also makes use of compression, but it is not at the expense of quality. When there is a certain number of identical pixels in an image, instead of describing each pixel separately, in this type of compression only the first pixel is described and then multiplied by the total number of the pixels identical to it. Unlike JPEG, however, the pixels themselves are not changed which gives us reason to say that there is no loss of quality.
On the downside, TIFF comes with large file size and as a result they are recorded more slowly and take up a lot of space.
RAW is the raw information which comes directly from the sensor without any preliminary editing. This information is usually 8, 10, 12 or 14 bits per pixel. There are numerous advantages to this file format, because the image is not processed in any way and the white balance is not set. In fact, using a suitable converter you can make a number of settings after shooting, such as white balance, sharpness, contrast and even exposure adjustment within certain limitations. A disadvantage is that you cannot open this graphic format without using additional programmes such as Adobe RAW Converter (ACR), Adobe LightRoom, Capture One and others, as well as the large file size compared to the JPEG format. Sony A7iii features two types of RAW format – compressed without any loss of data and uncompressed. A 32GB memory card can save up to 1250 photos in the compressed RAW format and 650 in the uncompressed format, respectively.
Advantages of the RAW format:
- no gamma correction;
- no changes in white balance;
- no colour changes;
- losses are fewer compared to the TIFF format;
- records data in 10, 12 or 14 bits.
Disadvantages:
- Requires special programmes to open files;
- Image editing takes 20 – 40 seconds;
- There is no universal RAW standard and each manufacturer, even each individual camera, may have a different standard for this format.
The RAW format is comparable to an undeveloped film. It gives you ample opportunities to edit and obtain higher quality images, if you are willing and patient enough to edit each photo separately, but it is pointless to use this format for everyday casual photography since it is time-consuming and requires specialised programmes and a powerful computer.
It may not be necessary to shoot in RAW all the time, but in many situations under difficult light conditions it makes a remarkable difference and you will have more opportunities to make corrections later. Having this in mind, if we you are adamant on having the highest quality possible, you should use RAW. The examples below illustrate the reasons why RAW is the superior format.
Generally speaking, the JPEG vs RAW debate can be simplified to speed vs quality. It all depends on what your priorities are. JPEG photos are ready to use and can be sent right away. This is the reason why most reportage photographers shoot only in JPEG. On the other hand, when we want maximum quality, depth of undertones and dynamic range, then we should shoot in RAW.
To sum up – you probably remember the unforgettable 70s children’s movie ‘With children at the seaside’. In the film young Pipsi told Kircho ‘Real amateur photographers develop their own films and photos’. If you are a real amateur photographer, then shoot in the Digital negative – the RAW format, and develop your own photos using contemporary programmes analogues of the dark room. Great satisfaction guaranteed.
.
Sometimes you can tell a large story with a tiny subject.
Eliot Porter