Mel Raab, a reader from Los Angeles, has started experimenting with Raw
files and would like to know more about them. There are some benefits to
using them and some disadvantages - it’s always good to try out new
ways of working to see if you can benefit from them.
Raw files and Jpegs
Inside
a digital camera the optical image is focused onto a sensor that
converts it into millions of bits of “raw” data. A powerful
microprocessor then formats the data so that it can be saved to the
memory card and viewed on a screen. By default it’s saved as a Jpeg file
- the standard, universal picture format that all personal computers
can open. Whatever camera settings you are using at the time, such as
the color balance, contrast, saturation, exposure, are embedded into the
Jpeg file.
Many cameras also allow you to save Raw files in
which the camera settings are recorded but not directly applied to the
raw data. Raw files can be opened afterwards and the settings adjusted
to you liking. You can then save the result as a Jpeg, or another format
that you prefer.
Benefits and drawbacks
Raw
files are a good way of protecting yourself against mishaps. For
instance, in difficult lighting situations your pictures could have a
strong color cast. The cast would be embedded into a Jpeg file and the
picture could be unusable. If you had saved the picture as a Raw file
you could open it in your computer and adjust the color balance to
produce a useable and improved picture.
Many photographers now
save both Raw and Jpeg files of each picture, the Raw file often acting
as a backup of the Jpeg. This can take up a lot of space on a memory
card, however. At weddings I may shoot over 2000 images and if I save
each one in both formats they can be tedious to handle. Fortunately it
is possible to download only the Jpegs and leave the Raw files to be
used only if needed.
Camera makers use their own proprietary
brands of Raw files so you may need additional software or plugins to be
able to open them. Different versions of Raw processors can give
different results and you may need to experiment to find software that
suits you. Years from now it is conceivable that you might get stuck
with outdated Raw images that can’t be opened, but I expect that the
ubiquity of Jpegs will have made them future proof.
A useful trick
“Extending
the dynamic range” is photo-speak for bringing more detail into the
highlights and shadows of your pictures. Tweaking Raw files can add a
little extra detail to the shadows and highlights so it can be useful in
critical shots that require your best attention.
There is,
however, a trick that you can use to “extend the dynamic range” of
humble Jpegs: In the shot below, you can see that the camera cannot
capture detail in both the highlights and shadows, so the auto-exposure
has favored the mid-tones.
Detail
that is not recorded cannot be recovered afterwards, whatever format
the picture was saved in. I needed to record more highlight detail so I
adjusted the exposure compensation (the “+/-“ feature on your camera) to
reduce the exposure by about one and a half stops, ie “-1.5”, and took
the shot again. Afterwards I opened it in Photoshop and used some Curves
Adjustment Layers to selectively adjust the brightness and contrast of
the darker tones to produce the finished picture below:
I
might get extra detail through tweaking a Raw file, but it’s amazing
just how much shadow detail can be revealed using this method with
Jpegs. We used the same trick in the days of film capture: “Expose for
the highlights, develop for the shadows” was our motto.
When you
choose a camera, whether a compact or a dSLR, always look to see if
there is a dedicated “+/-“ button. This is too useful a feature to be
awkwardly buried in menus. On my dSLR it only takes a second to adjust
the exposure compensation and I don’t even need to take the camera from
my eye.
Many cameras can now do this trick automatically for you.
Some Nikon cameras have ADR settings to boost the shadows and protect
the highlights. As with anything to do with technology, you need to
practice with your specific equipment and judge what is useful for you.
A personal view
I
save my pictures as the largest, finest quality Jpegs and judge the
quality, sharpness, color, contrast and exposure from the instant
preview on the back of the camera. I also refer to the color histogram
display for more precise data, and adjust the camera and flash settings,
or use whatever else is needed to ensure a good result. I worked for
many years shooting only transparency film and had to produce the
finished, final picture on the spot in every sort of location and
situation: I use the same approach with digital capture. I use Raw files
if I need to, particularly in difficult lighting situations.
How
we capture and process pictures has changed enormously in the last 180
years and for me is the least interesting part of the job. Photography
is all about creating good pictures and it’s important to develop a
good, practical understanding how the quality of your pictures is
affected by backgrounds, visual awareness, story-telling content, the
use of position and distance, and the ability to critique as you shoot.
The
hi-tech nature of digital image capture can be quite addictive and it’s
easy to spend time analyzing pixels on computer screens rather than
practicing how to take good pictures. Use whatever is best for you, but
please don’t get sidetracked by technology: There are countless superb
pictures that have highlights or shadows that lack detail. Many of my
absolute favorite photographs were taken with technically inferior and
gritty black and white film in very basic cameras. For me it’s the
ability to take a good picture that counts first, foremost, and last.
Picture Clinic
If
you would like to develop your photography skills, you are welcome to
send to me one of your pictures that I may publish with some
constructive feedback. Upload your picture here: http://www.clinic.langford.co.il
Tom Langford is an Event and Commercial photographer: http://weddingseventsisrael.com & http://www.langford.co.il
Details of his next photography and retouching courses in Israel: http://www.courses.langford.co.il.
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