There are several types of file that can be stored on a digital cameras memory card. Some offer space-saving compression to maximise the number of photos you can take and store on one card. Others offer a staggering amount of digital data that can be manipulated in post-processing. There are three main types used by digital cameras:
The file types used by digital DSLR cameras are:
- JPEG (Joint Photographic Experts Group) Compressed to save space.
- TIFF (Tagged Image File Format) Uncompressed files for storing bitmapped data.
- RAW (As it sounds) Uncompressed, unmanipulated raw data ideal for post-processing.
Let’s have a look at a little more detail about these file types as they are used in digital photography.
JPEG – Created by the “Joint Photographic Experts Group” these files can support 16 million different colours and hues and also varying degrees of compression up to 10 times with little degradation. Their use is popular in photography and digital cameras as the compression reduces their size so more images can be stored on the memory card.
The files may also contain useful metadata to describe the contents and provide camera settings data such as aperture setting, shutter speed, focal length, ISO number etc. There are several drawbacks to using the JPEG file type in photography though: The “Lossy” compression can cause the formation of “Artifacts” which can make parts of the image look blocky which is not ideal for high definition prints.
Also, the JPEG format does not support transparent pixels so it is not ideal for saving non-rectangular images that need to be printed on coloured backgrounds.
TIFF – Tagged Image File Format. This file type is very large, uncompressed and doesn’t lose any of the photographs data. These are “Lossless” file types and not many DSLRs can save in this format. These files will probably be used in high-end graphics publishing and medical imaging rather than photography but some photographers still use them.
The files are just too huge to be practically used in internet-based transfers so they have to be compressed into a more manageable size before transmission.
RAW – The name says it all. These are large, uncompressed and unprocessed files. They are the go-to choice for professional photographers as there is a great deal of data to aid the post-processing of images. It is as close to film quality as you can get. It is sometimes referred to as a digital negative as it retains all the information from the camera’s sensor.
Post-process editing of a RAW file is non-destructive and you can always return to a previous version. Once you have finished editing you can save a compressed version like a JPEG that is more manageable for web-based uses.
RAW files are very large files and they are incompatible with some imaging and viewing software. Specialist software is required to view and manipulate them. There isn’t a standardised version of the RAW file type and all the camera manufactures have their own versions.
They can all be opened by programs such as Lightroom and Photoshop though. There was an effort by Adobe to create a standardised RAW fils type called DNG (Digital Negative) but it didn’t catch on.
What is Dynamic Range in Photography?
Different files types can record varying degrees of Dynamic Range in a camera. To discover more about this subject, click here.