who don't use raw files are sometimes confused as to what they're all
about so I decided to write this little help sheet.
you take a photo with your camera you are allowing light coming
through the lens to pass through the shutter and fall onto the
sensor. The sensor detects the light colours and strength as
information, or data, records it into memory, then converts or
processes it into a picture file, almost always a JPG, (some use
JPEG) and compresses it, like you would Zip a Word document.
you can set your camera to do certain things when it converts the
data into a picture file. You can tell it to drop all the colours and
have only Black and White, you can tell it to add a filter to make
the picture sepia, or you can add simple things like a little extra
brightness, more contrast, and even a little sharpness. This all
happens when you take the picture and you don't see anything going
on, you simply see the preview screen show you the shot you just
cameras allow you to save to JPG Small, Medium and Large, or Fine.
JPGs are compressed data as said and some of the data can be dropped
without most noticing any difference. This saves on space mostly but
as space in computers is relatively cheap now, there's little point
in choosing any other than the best quality option. That is, the
then transfer the JPGs to your computer and edit them in photo
editing software (list of programs available coming soon)...or
not! Most people edit to a small degree, even if that's fixing
the horizon cos it's wonky, adjusting the exposure cos it was too
dark/bright, or enhancing the colours by saturating them slightly.
cameras allow you to save in TIFF or DNG format, we'll not worry too
much about them here.
cameras nowadays have a setting also called raw. Unlike TIFF, JPG and
DNG, raw doesn't stand for anything. That data that your sensor
collects, it's just unprocessed, or raw data, it's RGB values for
each sensor pixel. That's why it's called raw. Most cameras allow you
to save a raw file and a JPG at the same time. This is simply so you
have a JPG file you can look at quickly once it's on your computer.
When you've decided which ones you're going to keep, you can delete
all the JPG's if you like.
do anything with this raw data you need some software and everyone
uses the software that they prefer. My preference is Lightroom, but
there are many out there, some are even freeware, free to download
and use from the internet.
you open the raw file in whatever software you use, it does what's
called de-mosaicing. This is a term which simply means the software
reads the data, and presents it in a form that you can see on screen.
You may notice that at first the picture isn't as pretty as a JPG,
but that's because the camera didn't choose how to convert that data
like it does with JPG, it's sometimes flat and doesn't look very
some programs like Lightroom can do what is called 'non-destructive'
editing. What happens is this:
loads the raw file and de-mosaics it so you see an image. You can
alter that image in many ways and Lightroom keeps a record of what
you did in a special file so each time you load the raw file it also
loads the special file and shows you the image as it would appear
with your changes.
you are happy with all the changes you can then export a JPG from it.
The raw file is still untouched, the special file still retains all
the edits you made, but the JPG is there for you to do with whatever
here's a beautiful thing. In fact 2 beautiful things.
time you view a JPG you are actually decompressing the compressed
file (remember I said earlier it's like a compressed zip file?) and
when you close it you are re-compressing it. Every single time you do
this with a JPG you lose a tiny bit more detail, this is called lossy
compression. So over time the JPG deteriorates. If that happens or if
you simply lose the JPG, you can go back and export another one from
your raw file. There is no limit to how many you can export. You can
even export one small JPG for your Facebook, a larger one for your
blog and a much larger one to print out.
say you miscalculated your exposure and it's slightly dark. No
problem, use Lightroom or other raw processing software to give more
exposure. Raw files allow you approximately 3 stops over and under.
What they can also do is allow you to slightly darken a too-bright
sky, but slightly lighten a too-dark shadow. Then when it's right,
export your spot on JPG. There are a myriad of alterations you can
make in raw software and the beauty is you can simply click 'reset'
and your raw file is back instantly to how it was when you first
transferred it from your camera. Both Canon and Nikon cameras all
ship with their own software too so you don't have to buy a separate
program if you don't want to.
can't break anything and making digital costs you nothing, so why not
try raw and see what you think?
(pronounced jay peg) stands for Joint Photographic Experts Group, who
first determined how JPEGs would work. They're usually called JPGs
simply because file extensions in Windows only used to be able to be
3 letters, hence myphoto.jpg. This is still the preferred and most
commonly used file format, although often produced from a raw file.
are Tagged Image Format Files and they are not compressed like JPGs
are, so take up lots more room.
is Portable Network Graphic. This format unlike JPG's does not lose
info each time it is compressed and was made to replace the GIF which
has limited or no use in photography. It's use is highly debatable.
is Graphic Interchange Format and only contains 256 colours so is not
usually much use to digital photography.