I find that the easiest way to visualise what’s going on is to think of a photograph
printed on paper that you then crush and put in a small box. When you take it out
the box and unravel it, there will be some creases on it. If you crushed it to fit
in an even smaller box, it would have more creases and be lower quality. This is
more or less how jpeg works in practice except you don’t get creases on the image.
What you get are jpeg artefacts. There are two forms of these. One is odd wiggly
lines around any well defined edges the other is what looks like square blocks on
areas that should be one flat colour.
The best thing about jpeg is that, if you use low compression (high quality), the
image hardly suffers at all. Most people wouldn’t notice anything wrong yet the file
can be as little as 10% of the size of an uncompressed file. Allowing your memory
card to hold 10 times more pictures.
The worst thing about jpeg is the fact that the artefacts it creates in your image
are permanent and part of the saved image. This is important if you intend to edit
your image and save a new version. Every time you save a jpeg, whether in your computer
or your camera, you create these artefacts. So, if the image was a jpeg to start
with, after some editing you might find the final quality to be less than you expected.
The quality setting on your camera is usually found in the main menu near the size
setting. If your only aim is to get the maximum number of pictures on your card,
then both size and quality need to be at their minimum to achieve this. Quality options
usually consist of low, medium and high. High is the one you need if your pictures
are intended for anything other than personal use.
For those who don’t intend to edit, publish or sell their pictures, it’s just a matter
of personal taste. If the low quality setting looks good enough to you, then use
it. You will gain space for a few more pictures on your card.
As with the image size setting, the quality is often set to medium by default. This
compromise is unlikely to suit anyone. It is much more likely that you would want
either the best quality or the greatest number of images on your card. The medium
setting gives you neither.
Other file formats
In most cameras, the quality setting affects the way your digital images are saved
in the jpeg format but some cameras can save images in other formats, notably tiff
or raw. In terms of quality, both these formats represent the highest your camera
can produce, but they are quite different from each other. You are very unlikely
to have both options in your camera, but your highest quality setting may be producing
tiff or raw image files.
The tiff format is uncompressed. That is the main difference between it and jpeg,
but it’s a big difference. An uncompressed image file is enormous even when compared
to a high quality (low compression) jpeg. So much so that it may be impractical to
use it unless you have a large memory card installed. Also you may find that there
is hardly any difference in quality between tiffs and jpegs with low compression.
Tiff files are really only practical when you absolutely must ensure that you get
the maximum quality image your camera can produce.
This file format is very different from the other two in that it needs specialised
software to even see the image. This software should come with your camera or you
can get it from the manufacturer. Raw is actually a general term for several formats.
Each camera maker has their own proprietary version and they are not compatible;
however, there are independently made programs that can read and process many different
In terms of image quality, raw files are every bit as good as tiffs but usually not
so large, although they are still much larger than jpegs. As long as you have the
correct software and a large enough memory card, saving your camera images in raw
format is the perfect way to guarantee maximum quality.
It is definitely worth checking the size and quality settings on your camera. There
is an enormous difference between a small low-quality digital image and a large high-quality
one. Which one you need depends on how you intent to use your photographs. One thing
is certain, very few people will find the medium size and medium quality setting
to be the best one for them but these are probably the settings your camera will
have when you first start to use it.