WHY I SHOOT RAW
By john gilbert
I have said it before and I will repeat it now, shooting in
jpeg throws away valuable recoverable data.
Furthermore, when you shoot jpeg you are letting the camera “post
process the image for you”. Don’t
believe me? Do this test, go outside and
shot a picture and shoot it in jpeg and then shoot it in RAW. Download the two pictures and compare the
file size of the jpeg with that of the image shot in RAW. You should note a huge difference in the
number of megapixels which make up each image.
The RAW file, depending on your camera, can be twice as big as the jpeg
file. So what happened to all those
megapixels? The camera post processed
the jpeg image based on the camera’s internal stored memory data and then
discarded all the pixels it did not use.
Threw them away not be seen again, co-poof, gone. No chance of ever recovering detail in post
processing. Did you know that the
discorded data could be up to 61% of the total that could have been captured? The next images were taken with a Nikon
24megapixel camera, Nikon D750. (Click on an image to enlarge it.)
The above image was captured as a jpeg right out of the
camera and consisting of 11.92MB and at a resolution of 300ppi. When
you compare this to the image below (Image II) it is obvious that the camera
has applied some processing. The RAW
file below is muted or dull and flat in appearance. (Click on an image to enlarge it.)
This second image is the unprocessed RAW file and contains
28MB of data, just waiting to be processed.
Note the difference in the sizes of the two images, 11.92MB for the jpeg
and 28MB for the RAW file. That is a
loss of data of approximately 57%, this will differ with various cameras but
the principal will always be the same.
What happens to that data? It is
lost.
So what is so important about this? The ability to recover highlights and shadows
in post processing is lost. Many times,
as I will show later in this article, data can be recovered in processing. Today’s cameras have the ability to record a
large amount of dynamic contrast, the difference between lights and dark, which
can be brought forward in the digital darkroom (computer).
Let’s look at image III taken with a Nikon 36megapixel camera, Nikon D810. Even though I used two different cameras from different periods in time the principal of lost data from shooting jpeg versus RAW is the same. Just for information this was captured at Millstream Gardens on the St. Francis River. This RAW file is 76MB in size. The jpeg version of this image would be about 29MB or 61% less data. Note here that the sky appears to be washed out or overcast. However, on the day this picture was taken there were in fact clouds in the sky. But standing in the shade and shooting a scene that has a bright sunny background is definitely a high contrast scenario. But like I said today’s cameras can capture a large range of light/dark contrast. (Click on an image to enlarge it.)
So I am going to take this image into Photoshop and process
it to bring back the details not showing but were in fact captured by the
camera. How can I do this? Because the
data is still there in the RAW file, it was not discarded by the camera but in
fact was captured and stored on the SD card. This affords me the opportunity to recover as
much data in the image as is possible. I
usually begin with some general adjustments in a RAW processer. My RAW converter is “Adobe Bridge”. I use it
to set the camera mode, correct for “Chromatic Aberration” should any exist and
enable “Profile Correction”. I use
Layers in Photoshop to pull back the light and open up the shadwows but this
can be done in “Bridge” or “Lightroom”.
Before we go any farther lets
explain Chromatic Aberration and Profile Correction. Chromatic aberration (also known as
color fringing or dispersion) is a common problem in lenses which occurs when
colors are incorrectly refracted (bent) by the lens, resulting in a mismatch at
the focal point where the colors do not combine as they should.
It can appear as a green or
red fringe around the sharp edges of your subject. Chromatic Aberration happens because
your lens acts as a prism; bending light depending on the various properties of
the glass.
Profile correction allows you
to fix lens problems such as distortion, chromatic aberration, and vignetting.
There is a lot that can be done in “Bridge” or
“Lighroom” and for general purposes you should be able to accomplish everything
you need in these programs. You can
adjust the temperature, to make your image cooler or warmer. Adjust contrast locally or globally. Pull back the highlights in case there is
some spiking of them and open up the shadows.
Adjusting clarity can make a picture appear to be sharper and you can
even apply sharpening and reduce noise as well.
You can also adjust the saturation of colors globally or increase
non-saturated colors by adjusting the vibrancy slider.
Image IV is the completed processing of the RAW file. Note that I was able to recover some really
nice clouds, opened up some mid-tones or shadows, brought out the colors, and
increased the overall sharpness, all without distorting any parts of the
image. Because of the file's size I could
enlarge this picture for printing without any loss of detail. (Click on an image to enlarge it.)
I should point out
that shooting in RAW will require more processing time and this can be daunting
if you have taken hundreds of shots.
Today’s software’s make it possible to process one image and then copy
the adjustments to subsequent images.
There are hundreds of presets available to aid in the processing task as
well as plug-ins like NIK and Topaz or even On1.
I shoot in RAW but there
are times when jpeg is the way to go.
For example when I shoot a sports event like a high school football game
I will shoot in jpeg. I have even been
known to shoot wildlife in jpeg and RAW at the same time. Now there is absolutely nothing wrong with
whichever method you prefer and with cameras offering 36 to 50 megapixels there
is a lot of room for adjustments even in a jpeg file. I have seen some drop dead gorgeous landscape
images that were taken in jpeg mode. But
to capture that breathtaking sunset or sunrise or any dynamic range landscape I
encourage you to shoot in RAW format.
Beside for me post processing can be as much fun as actually taking the
image. Well maybe the next best thing to
taking the image.
