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Mailbag: RAW or JPEG?
By Ethan G. Salwen
Editor's Note: From time to time, we receive mail from
Rangefinder and AfterCapture readers and WPPI members asking for
guidance. A recent email brought up the topic of RAW vs. JPEG shooting. Ethan G.
Salwen, a regular contributor to Rangefinder and AfterCapture,
has some great advice below.
A Reader Asks
Reader Bob Ruthrauff is a photographer who shoots wildlife and environmental
portraits of families. He has been shooting with both RAW and JPEG and doing basic
editing in Photoshop: straightening horizon lines, adjusting levels and contrast,
and color-correcting. He sends his images to a pro lab for printing.
Bob writes, "I've accumulated lots of information about digital photography in
the last several years, and it generally indicates that I should be capturing
the most information possible with each image. Recently I've had conversations
with the instructor of Photoshop classes at the local community college and the
technical director of the professional lab that I use. Both say that printers
do not print 16-bit color depth produced by RAW files converted to TIFFs. The
technical director also said that RAW's chief benefit is to rescue poor
exposures, and that 16-bit color probably can't be seen by the human eye."
Bob wonders whether it is worth shooting RAW files and dealing with large file
sizes if the resulting images are being printed at a lower bit depth. He adds,
"If the human eye can't see more than 8-bit color depth, what's the sense in
trying to produce it?"
Ethan Responds
You ask a number of good questions regarding the RAW vs. JPEG debate, and you
have clearly done a lot of homework as well as thoughtful testing. You also have
firsthand experience that JPEG files can produce prints of equal quality to images
captured in the RAW format. Therefore, your question of shooting RAW or JPEG is
a highly valid and understandable one.
You should know that there are many ways to answer your question, and that
different experts will have different outlooks, attitudes and experiences. You
should keep this in mind when deciding what works best for you. There are many
books and other resources online to help you evaluate your needs. However, you
will find that photographers of all types are increasingly turning to RAW capture
as the best default mode to meet their needs. I will explain a little about why
this is happening.
First however, in an increasingly pro-RAW world, it is important to note this
honestly: If JPEG capture is working for you with 100% consistency, there is no
reason to necessarily embrace the RAW file format. JPEGs have smaller file sizes,
and they do not require RAW conversion, which can be a time-consuming process that
requires an additional set of skills. JPEGs are particularly well suited for news
journalists and high-volume photographers, such as event photographers and wedding
photographers. (Though this is changing quickly.)
That said, the RAW workflow is becoming increasingly easy to embrace, yielding
greater benefits with fewer drawbacks. This can be seen by the fact that more and
more wedding photographers are turning to RAW workflows, realizing that the benefits
often outweigh the costs, and that the costs (disk space and processing time) are
actually decreasing all the time. In short, shooting RAW becomes a win-win situation,
and it is possible that you have simply not had the opportunity to see the benefits
yet. But when you do--let's say you blow out the highlights in exposing a critical
JPEG--you will wish you had captured the image in a RAW format.
Let's get to your most pressing question: Why shoot 16-bit RAW files when a
printer can only handle 8 bits of information? First of all, note that few
digital cameras actually shoot in a 16-bit mode--most actually shoot in a 12-bit
mode, with the additional information being interpolated during processing. Still,
12 bits provides phenomenally more information than 8 bits. Furthermore, I believe
the real answer you are looking for is this: If you start out with 16 (or 12)
bits in the editing process, each stage of (destructive) editing will have less
of a noticeable effect when the image is eventually converted to 8 bits (or
output on an 8-bit device). In short, your observation that more information
is better really is true, and this is something that you will particularly see
when you have problematic files.
Again, you might not be noticing these effects with your JPEG files if you are
making perfect exposures and if you are not doing much editing. But if you
underexpose an 8-bit file and then try to redistribute information to the
highlight side of your histogram, the noise you see will be seriously unacceptable.
One way you can test this is to convert the same RAW file into a Photoshop file at
16 bits and 8 bits. Then go through a series of fairly drastic edits, checking your
histogram at each step of the process. You will notice that as you stretch and
squeeze and manipulate data, the image that started out at 16 bits will hold up
much better, and it will have much more integrity when converted to 8-bit for final
output.
This said, sometimes--whether shooting in JPEG or RAW--8 bits is all you need.
And it is for this reason that RAW-conversion programs give you a choice of
selecting the number of bits you want to retain during the conversion process.
For example, when I run a batch process to produce work prints from Adobe Bridge
via Adobe Camera Raw, I set the workflow options in ACR to 8 bit, knowing that
for this purpose, the lower number of bits will greatly speed the process. However,
I am not affecting my original RAW capture, which I can always reprocess--either
at 8-bit or 16-bit--depending on my needs, my client's expectations, and of course,
the quality of the file.
RAW files (and conversion software) are indeed fantastic for recovering blown-out
highlights. But the advantages of RAW files go way, way beyond this. As I imagine
you know, the RAW file captures all of the image data, and then you can reprocess
that information as newer softwares are developed. In other words, I can process
the same CR2 RAW file from a "legacy" camera over and over again as software
advances, while a JPEG has already been processed--once and only once--by the
onboard computer at the time of exposure.
If you used Photoshop CS2 and have switched to Photoshop CS3, you will notice
a massive number of RAW-processing advantages in Adobe Camera Raw 4.1 (especially
in sharpening and noise reduction) that you can apply to the same file. Not so
if you were shooting with JPEGs.
Personally, I like to steal the Spider-Man tag line when thinking about the
advantages of RAW files: "With great power comes great responsibility." Working
with RAW files is all about potential. And as a photographer, don't you want to
give yourself the most potential at every step in the process?
Again, in the name of honesty: Don't let anyone fool you into thinking that
working with RAW files offers a panacea for lack of knowledge and practice. You
can easily squander the potential of a RAW file. For example, many people do not
understand the drastic effect that ISO plays on all digital captures. A photographer
making excellent exposures in JPEG mode at ISO 100 is likely to get much better
results than a photographer making bad RAW exposures at ISO 1600. Still, it is fair
to say that the pressure is much, much greater with JPEGs: In-camera color balance,
sharpening and exposure have much more dramatic (and irreversible) consequences.
If JPEGs are giving you great results, I will not try to lead you away
from that. But the RAW format is incredibly more robust and dynamic, and the whole
industry is moving in a direction of better support for RAW files. Consumers--who
need quick, good-looking shots--will continue to shoot JPEGs (which of course,
actually start out as RAW captures), but professionals like yourself who are
doing portraits in high-contrast scenes, and who want to have complete control
over their crafts, will want to use RAW, and they will continue to appreciate
the RAW-supporting software developments that are coming down the pipelines.
I hope this brief answer on a complex question has helped. As a bit of warning,
let me add this: It seems that part of your question comes from the fact that you
have not yet encountered major problems with JPEG files. This suggests you are
very careful about your exposure, in camera color balance and sharpening, and
so forth. This is great. But if you run into a major problem (and I hope
you don't) with JPEG files on an important shoot, then you will
understand the power of RAW, and this whole question will be negligible to you.
In my opinion, RAW is the only way to go.
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