Understanding
RAW Format
by
Alton Vance
All digital cameras take their
original image in some kind of RAW format. RAW files are usually proprietary
to the camera manufacturer and sometimes to the specific model of camera.
That means, only the camera that takes the picture can understand the
information collected on the camera sensors. That information is then
translated by means of firmware (software) built into the camera and the
usual result is a more user friendly format called JPEG. That is why most
cameras produce images with an .jpg extension. JPEG is a compressed format
(and has the ability of varying degrees of compression). JPEG has become
a fairly universal digital standard for photo images. The one big advantage
of JPEG is that it takes less storage space than the original RAW file.
What happens is that all digital
cameras use firmware to apply various qualities to the RAW format before
it is translated and written to the memory card in JPEG form. The firmware
in the camera will apply varying degrees of sharpening, varying degrees
of saturation, varying degrees of contrast, etc. Most cameras have facilities
to change these settings to the photographers liking. The only hint you
have of what that photo will look like is the small LCD on your camera.
This is usually too small to tell enough to make changes until it is too
late. Often the photographer doesn't want to mess with those changes on
the field anyway. So you set your camera based on the last experience.
Many people never experiment with changing these settings anyway.
The Advantages of
RAW format (Menu)
Thus enters the advantage of
shooting RAW. The RAW information settings can be set in the software
after you get the image home or downloaded to your computer where you
can see the image on your large computer screen before you develop it
into JPEG. There are three RAW software publishers (which I discuss below).
Two of which I use and I'm sure there must be others of which I am unaware.
Many digital cameras still
do not give you access to the RAW format so JPEG is your only choice.
These are usually the point and shoot digital cameras. But for those of
you who have RAW available and would like to experiment with the versatility
of RAW format may want to give consideration to the following information.
RAW conversion Software (Menu)
The software for RAW conversion
comes from three publishers that I know of. Adobe Photoshop CS and CS2
(the latest version) reads RAW format for most late model digital
cameras. Phase One publishes RAW format conversion software
called C1 for most (but not all, though they continue to
upgrade quickly) professional and prosumer cameras. Another publisher
just recently published an upgrade to their software called Bibble.
You can download a trial version of Phase One and Bibble. I found this
to be quite helpful in making my choice.
I prefer C1 for
its workflow ability over Photoshop and Bibble.
For me C1 is better for mass development (when you have a lot of files
to work with). However I use Photoshop when I have just one or two
files to work on because it is convenient to have the file in Photoshop
for further processing if desired. I have noticed that each of these titles
give somewhat different results in development - one good reason to try
out their free trial versions. You might prefer one over the other but
if you already have Photoshop CS you probably won't want to invest $99
to $500 in C1. C1 comes in various versions
with different features but quality is the same in all versions. However
if you are still using an earlier version of Photoshop, a reasonable decision
would be one of the lesser versions of C1 (http://www.phaseone.com).
Bibble (http://www.bibblelabs.com)
is another choice but after using C1, Bibble seemed to be
rather awkward to me. After some experimentation I found that C1
and Photoshop CS both produced images with less noise. Although
I must admit I have not spent as much time trying to get a good result
with Bibble.
All of the software packages
above allow you to adjust exposure settings by plus or minus two stops.
This can be one of the biggest advantages of shooting RAW. You can make
adjustments, as slight as it may need, as if you were doing it in your
camera at the time of exposure. (Although I do recommend an accurate exposure
at the time of shooting. That will still result in the best detail.) Also
you can adjust settings for saturation, contrast, sharpness, white balance,
etc. just like the settings in your camera would have done, but now you
can adjust it as many ways and as many times as you want for each picture
and see what's happening with each adjustment before it is developed.
For me one of the wonderful features of RAW and perhaps the one that makes
the biggest difference is the ability to correct white balance in post
processing - once white balance is set in the JPEG you are stuck with
it. You can make slight changes with color balance in Photoshop but post
processing white balance is so much more effective especially with digital.
Digital cameras have the wonderful ability (unlike film) to change white
balance with every shot. See my article on UNDERSTANDING WHITE BALANCE.
A RAW file might be considered
similar to a film negative with adjustments.
Disadvantages
of RAW format (Menu)
One big disadvantage of RAW
files: they are large and take up 2 to 4 or more times the space of JPEG
files, depending on the compression choice you use in JPEG. So keep in
mind your storage space when making a decision to use RAW.
When making a choice to use
RAW files there are three other things to consider.
Number one: RAW files cannot
be saved back to RAW once they are converted to JPEG. The advantage of
that is your original RAW file is never changed nor is any information
lost in compression because you cannot re-save to the original file. So
your original information is always left intact. I understand that every
time you save over an original JPEG file it is further compressed each
time you save it. If you loaded, edited, re-saved, closed then opened,
edited, re-saved, and closed a JPEG file 100 times you would see considerable
degradation in the resulting file. (The solution to that dilemma is to
always rename your file so you do not save over the original JPEG.)
Number two: If you need to
save space you can always delete your RAW files after you have arrived
at your best settings and converted to JPEG. Personally I like to choose
my best shots and keep the best RAW files and save over my JPEGs. If the
JPEG gets degraded I can always go back to the original RAW file and develop
again from the original information. (However keeping my RAWs may mean
buying a larger hard drive or two down the road. I already have a 160
gig more than half full.)
Number three: It takes considerably
more time to develop RAW files than to have the JPEG already finished
out of the camera. It has taken my son quite awhile to see the advantages
of RAW solely based on this fact alone. It is just too much trouble for
some people. For me it lends versatility.
I do not in anyway pretend
to be an expert in RAW file development but I am sharing my personal experiences
over the past 1 and 1/2 years. Since the day I bought my Canon 10D I have
rarely (and then only accidentally) shot in straight JPEG. (I have shot
more than 8000 images in that period of time and have developed most of
them from RAW.)
What format is best? (Menu)
There are professionals who
shoot in RAW. There are professionals who shoot in JPEG and both do wonderful
work. It is somewhat a matter of your preference, your time, your space,
and your desire or need to have the extra flexibility of RAW format. My
son shoots and works for Michael Shaffer Photography (http://www.schafferphotography.com/)
and they still shoot most of their work in JPEG. I am the amateur hobbyist
who can take the extra time to work with RAW. I don't have deadlines to
meet. But sometimes there is the need to have that shot just perfect.
I've found that RAW format has been a big advantage at getting just the
right lighting, exposure, sharpness, saturation, and white balance, for
my landscape and nature photography without the loss of any post-processing
detail. I like RAW format a lot.
If I need to get a large batch
of photos ready quickly, I set the software to batch develop all the photos
at the camera settings, go have lunch and when I come back they are all
developed. Then if there are some shots that need more attention I have
the ability to come back to each RAW image and redevelop with more precise
settings.
I hope this is helpful.
These examples were converted
by the use of PHASE ONE C1 RAW conversion software. The only manipulation
performed on these two photos was sizing. Nothing else was manipulated
outside of PHASE ONE C1 RAW conversion software.
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