Although it’s certainly not the first question I’m asked about shooting, the topic of RAW vs JPEG does often come
up. It’s actually a fairly well discussed issue (Google it and you’ll many
people have given their views on the debate), but I figured that shouldn’t stop
me weighing in with my own views. In addition, in the near future I plan on
providing a couple of articles on the broader topic of workflow so I figured
this would be a good primer.

So, the topic of RAW vs JPEG. Almost all DSLR’s and several compact cameras
allow you to shoot in either (or both) and the question is what is the best. Or
to put it a better way, which is the most appropriate.

RAW is often called the equivalent to the “Digital Negative”,
a file format which contains all the data that was available to the sensor at
the time it was recorded, and written in a way that does not undergo any kind
of compression (there are exceptions to this but we’ll ignore that for now).
This means the format is “lossless”, which in itself means that no data (and
therefore image quality) has been lost in the process. Essentially, what you
see is what you get. Modern RAW image files from Nikon end in the file
extension “NEF”, while Canon images are called “CR2”. Note that the formats are
completely different – no universally accepted standard exists for a single RAW
format. As a result, you can’t really take a RAW file, process it and then
shove it up on the web for all to see as, among other reasons, you wouldn’t be
sure that everyone else’s PC would be able to understand the format you’d be
posting. So what you have to do is “develop” the RAW files. It’s an exciting
word and makes digital only photographers like me get excited that we’re locked
in our [digital] darkroom with the modern day equivalents of chemicals, Portra
and … stuff. What it actually means in reality however is that we just press a
button in Photoshop or another RAW converter (which supports the camera’s RAW
format), process it and then save it into something the rest of the world can
see… and that format? Well, given you’ve found this blog in the first place it
likely means you’ve actually photographed before – so it’ll be no surprise that
the format is JPEG. 

So, following the above premature introduction, let’s get to
JPEG which is the other option available to photographers. JPEG is a well known
image standard which is the dominant format for displaying pictures on the web.
Often shortened to JPG (which is also the extension used for JPEG images e.g.
picture1.jpg), these images are different from RAW in that they are “developed”
in camera. During that process, they undergo a conversion from the image data
captured by the sensor, compression and then are written to your camera’s
memory card in the JPEG format. Because of the type of compression normally
used, the format can be considered to be “lossy”, meaning that some visual
quality is lost during the process.

So what are the differences and importantly, what advantages
/ disadvantages does this practically result in for photographers. Lets run
through them now.

Image Quality

I always smile wryly when I see forum posts talking of the
value of shooting in RAW, particularly when a new camera has been released and
samples are doing the rounds on the net, and how the “real truth” of a camera’s
capabilities will be shown when someone starts posting RAW images. I am not
sure if it’s just a general misconception, whether that someone had a bad
experience with one (or the other) format or if there is something exciting
about “developing RAW” that makes it so preferred for that person. Whatever the
case, I think I’ll make this section easy and say this right now, that despite
the lossless nature of RAW and lossy nature of JPEG’s – 

it is very rare for
there to be any significantly noticeable difference in resolution / sharpness /
image quality between a RAW which was converted to a JPG using a PC and a JPG which
was developed in camera.

Now that’s not to say all JPG engines in cameras are created
equal but I would bet I could find a hundred photographers, show them a two 13x19”
prints and not one would be able to tell the difference between the two
pictures from a resolution perspective. That’s not to say there isn’t a
difference at all – if you check out DPreview’s reviews (and their obsession
with 100% crops), you’ll find some examples where you can see minor resolution improvements
with using RAW. My point however is that 99% of the photographic population
will never take advantage of that minor difference and other factors like the lens,
the quality of the image, scene setup, technique and so on will come into play
long before that marginal difference ever does. 

How do I score this section? Well, I’ll give it to RAW in
principal – but from a practical point of view, there’s not enough difference
to be able to say there’s an actual real world advantage for the vast majority
of people.

White balance and in camera settings

So, with the exception of exposure and ISO, most of the
settings applied by the camera to a RAW image are non destructive. In other
words the white balance, sharpening, saturation, contrast, etc – these can all changed
in decent RAW processing software on your PC. With JPEG’s, this is not the
case, set your Nikon to “Vivid” mode and the saturation enhancements will be “burned”
into the image. Put your Canon in Tungsten mode and forget to change it back
when you walk outdoors and all your images will be blue. 

Now, this difference is where the real benefit of RAW starts
to come in. RAW allows for you to make mistakes and allows for you to
experiment while undoing those experimentations on your PC later. A great example
of that being done can be seen on Chuck Inglefield’s blog here.
Of course, these changes could have been done with JPG’s also – but the problem
is that if you push the changes in post processing too far, then you will start
to see a degradation in image quality.

One other thing I should say on this particular topic is
that with RAW files, you can’t accidentally save over an image. This is
actually very useful and prevents mishaps –a problem I I had with JPEG’s on
more than one occasion (although in truth this was a failure of my backup
policy at the time rather than anything else).

So here we have a real and definite benefit. Now, the real
question is whether having this safety net and greater latitude for
experimentation is a big enough deal for you to shoot in RAW (particularly when
you consider the downsides of RAW which we get to later).

Exposure

So RAW records in 12 bits and JPEG in 8 bits and it’s another
example of something I see being touted as a savior for all things photographic
as (I have heard so many times), “with raw, you can adjust the exposure in Photoshop
later”. Well, it’s true – in Adobe Camera Raw for example there is a Exposure
value which you can set to +2.0 EV (for example) to correct an underexposed image.
The problem is that like with any post processing action which increases the
brightness of an image, it does so at a price – and that cost is that it
introduces a lot of noise into the image. In that regard it is nothing like correctly exposing the
image in the first place through EV compensation. 

A better argument would perhaps be in better highlight
retention due to the greater level of information available. 

Having said that, in either event (underexposing or blowing
highlights), there is definitely a case that RAW provides you with a better
ability to correct an image after and I do like this. The problem I have is
more with the fact that it’s ability to do so (at no cost) is vastly overrated
in many cases and is no substitute for exposing correctly in the first place.

Size and Speed

RAW images take up significantly greater space than JPEG’s. Nikon
has a compressed version of RAW which claims to be lossless which I always used
whereas RAW images from Canon on my 5D come out at about the same size anyway.
JPEG images however on either camera are much smaller which means more shots on
a comparably sized card and less storage space later. 

Another advantage of JPEG in this regard is the speed at
which the camera can handle it. It’s not as significant a difference as it used
to be a couple of years ago as DSLR buffers have gotten larger. A modern day example
of the difference would be say (on the entry level D40x) that it can handle 9
consecutive images in RAW at 3 frames per second, whereas can shoot at this
speed indefinitely in JPEG.

Out of the camera, there is of course a speed advantage in
the workflow process of not having to convert / develop RAW’s.

Conclusion

So does the major latitude of experimentation and image
correction warrant the extra space and processing time? Well, to date, I’ve
cared little about the slightly greater level of shadow detail / highlight retention
as I tend to try to exposure properly in camera (and hate the introduction of
noise from correcting horribly underexposed images). But despite that, for me, when
it comes to DSLR’s the answer is a definite yes. The safety net of being able
to set / reset white balance without any concern for the effect it has on image
quality is reason enough for me. The downside of the extra storage I find to be
an acceptable trade off – I don’t shoot thousands of pics per week. Having said
that, if compressed lossless RAW wasn’t available to me and images started pushing
upwards of 20MB, then I’d start to seriously look into carrying a gray card around
with me as it’s mostly laziness / freedom from that that causes me to shoot RAW,
rather than any obsessive desire to see minute benefits at 100% crops. 

Aside from that that tho, there are other reasons when I would
not use RAW. One of times I won’t use it when it’s available is if the shot to
shot speed suffers too dramatically. Compacts are almost always a culprit for
this – with writing of RAW images taken 5 – 7 times longer in many cases on
cameras where it is available. So on compacts, I’ll almost certainly use JPEG.

Another time I’ll shoot JPEG is if a camera doesn’t have a
RAW + JPEG mode. You see, while I capture / process RAW images, I actually
shoot in RAW + JPEG (where both formats are written for each picture) – with the
latter being important as I use it for previewing in the field on an image
viewer that will accept a SD or CF card. If I were to lose that capability, I’d
start to see a good case for me switching to JPEG (or switching camera). 

So that’s my take on the issue.

If you’re like me – you enjoy being able to either alter
white balance after the fact for creative purposes or hate carrying a gray card
– or if you’re nothing like me but love spending hours looking at images at
100%, then I wholeheartedly recommend RAW. 

If you’re shooting JPEG however, while I still think it’s worth getting into RAW processing (if only to use it as a motivator to understand processing more), I wouldn’t sweat it. Until I meet someone who can look at a large print and tell me it was shot in RAW or JPEG, I’ll continue to feel comfortable with my view that there’s little difference in actual real world image quality between the two.