Pretty much most cameras save the pictures they've taken into JPEG format, cell phone, compact cameras, etc. all use this format. But the more sophisticated a camera gets, for instance with a DSLR, you can have a choice as to what format you'd like to save your image files. This other image file to save in called RAW. First let's look in more detail at the JPEG format.
The PJEG format Image file
The term JPEG is short for the Joint Photographic Experts Group, the committee that created the JPEG standard for digital images when they first came about. The JPEG format uses a compression method to save the picture, making the picture file size much smaller than other ways of saving a picture. In the camera, once the picture has been taken the hardware of the camera selects and adjusts the original image data and then saves the picture into the JPEG file onto the memory card.
RAW Image File
A RAW image file on the other-hand is when the camera does nothing to the picture you've just taken and saves all the image data as it is, a bit like a film negative. But as the work that the camera has done in editing the picture before converting to a JPEG (such as adjusting white balance, colour saturation, etc.) you now have to do this yourself on the computer. Let's look at some the advantages and disadvantages of these file formats:
Advantages and disadvantages of RAW
- You control the whole post processing to get the image you want... altering white balance yourself, contrast, sharpness.
- Bypass some of the cameras automatic adjustments you don't want done when saving pictures such as adding sharpness, or noise reduction, giving a truer image to work from.
But...
- RAW files take up more space on your memory card
- Time taken up on post production of images
- Cannot print straight from the camera
Advantages of JPEG
- Picture is saved with adjustments done in the camera already and is ready to be downloaded and printed straight away
- Smaller image files
Disadvantages
- The lossy compression: there can occur that the more the image is saved in JPEG format, the loss of detail you'll start to see.
- Camera's hardware alterations to the original image data
Other Aspects effecting Image Reproduction
ISO rating. ISO comes from the days of film photography when the ISO number correlated to the size of the grain of the film and therefore the graininess of the picture quality, and the fastness of the film itself. Bigger grains (higher ISO number) equals a faster film as it could capture light much quicker than smaller grains, which being small however could get more detail in the photograph.
Similarly in digital photography a higher ISO rating means that the image is capable to taking photographs in low light and/or fast motion situations but with more grain and lacking in detail. Try to use the lowest ISO option in your camera to suit your picture taking conditions ensuring properly exposed photographs.
