Shooting raw: a survival guide

//Warning: long post with a complete lack of pretty pictures of bikes...//

Update: since originally posting this I've added a few sentences (to clarify a couple of points), generally tidied things up a bit and rearranged the seven bullet points at the end into something approaching an order of priority.

The question of whether to shoot jpeg or raw is one that crops up a lot. If you're new to dSLRs, chances are you've been sticking with jpeg - it's seen as the safe option, and there's no immediate need to fiddle around with extra software to tweak the results. But if you want to get the best out of your camera, raw has a lot of advantages over jpeg (and it's not as tricky to use as you might think).

There's a great deal of information out there on the web around this topic, some of it downright inaccurate and misleading. So let's keep things simple.

If you shoot jpeg the camera does the raw processing for you, using all the parameters in your camera's image menus (sharpening, tone, saturation and so on) to tweak the result. If you shoot raw the camera records the data straight off the sensor and you import it into a software package of your choice, where you can fiddle around to your heart's content before exporting as a jpeg or tiff.

Here's how the two file formats stack up:

JPEG

Pros
- gives a ready-to-go result straight out of the camera
- doesn't need extra software or computer time
- reduces storage space

Cons
- contains less colour and tone information than a raw file (8 bits, compressed, for the technically-minded)
- reduces options for tweaking colour, contrast and brightness
- uses 'lossy' compression, which throws data out. Once it's gone, it's gone

RAW

Pros
- pulls the original data straight off your camera's sensor, unaltered
- acts as a 'digital negative' which you can come back to and re-process any number of times
- contains far more colour and tone information than jpeg (12 bits, uncompressed, typically), giving scope for more editing without losing quality
- allows post-capture tweaking of white balance, exposure and other variables not possible with jpeg

Cons
- needs extra software for processing and output to a useable file format for printing and viewing
- involves spending extra time at the computer
- takes up more storage space

(There are one or two myths surrounding raw floating around on the internet which are worth dispelling. One is that it increases a camera's dynamic range (the range of brightness values in a scene that can be recorded by the sensor). It doesn't do that, in fact, but it is certainly possible to make far bigger adjustments in software to a raw file than is the case with jpeg.

Another is that, armed with a raw file, the photographer can effectively make whatever white balance and exposure changes they like without affecting the quality of the outcome. In fact there's a visible difference between, say, a 2-stop underexposed raw file that's been recovered in software and one that was correctly exposed in the first place. Raw is no substitute for getting things right in-camera.)

The point, as far as I'm concerned, is this: if I shoot jpeg, I have limited options after I've pressed the button. If I shoot raw, I have far more flexibility at the expense of a little extra time spent at the computer. But that, in the end, is the crux for many people - is the time spent in front of a monitor worth the effort?

I think, on balance, that it is.

In the interests of making life a bit easier, here - in rough order of importance - are my tips for making the transition from jpeg to raw a bit smoother (including a few things I found out the hard way):

1. Accurate colour matters
If you're going to the trouble of shooting and processing raw, it's pretty important that your monitor is accurately profiled with a proprietary colorimeter and software package. If you don't take this step, you can't be certain that the colours you see on your monitor accurately reflect those contained in the file you're working on (chances are, they won't). And that means you'll never be able to print accurately. It's another expense, but it's worth doing for anyone interested in getting the best out of their dSLR.

2. Software design and performance makes a difference
The interface and performance (particularly in terms of speed) of your raw processing software is an important factor in how quickly and effectively you can work. There's a great deal of variation here, and personal preference certainly plays a part. But I have to say that most image editing software leaves a lot to be desired in terms of user-friendliness (or lack thereof).

Common problem areas include rendering speed (the novelty of watching a spinning wheel or eggtimer icon soon wears off when you've got dozens or even hundreds of files to process) and over-complicated screen layouts and tool palettes. How many different ways do you need to be able to tweak contrast, anyway? (the software I use has at least four...)

I've settled on Bibble because I'm used to the interface, it's blazingly fast at processing dozens of files at a time and the quality is pretty good. But apps like Apple's Aperture and Adobe's Lightroom set a new standard by making the entire process of downloading, organising and processing raw files far more intuitive. Well worth a look, if you can justify the price.

3. Getting it right first time saves time
Although there's lots more flexibility for making post-capture adjustments when you shoot raw, there's no substitute for getting things right in-camera. Not only does this mean your pictures will benefit from better quality, but you'll save a lot of time at the computer by not having to fiddle with all the basic adjustments. Nail the exposure and white balance to the best of your ability; you'll be grateful you did later.

4. Curves rule
Raw processors include powerful tools like white balance and exposure adjustments, but the most versatile tool in the box is also one of the simplest. Curves allow you to adjust the relationship between input and output pixels to alter image brightness and contrast. It takes some practice to achieve the effect you're after, but it's worth persevering with: curves allow greater control than any number of brightness, contrast or colour sliders.

5. Set your own 'look'
Don't be surprised if your software's settings give your raw files a disappointing look. Compared to out-of-camera jpegs, most raw conversion software defaults to relatively low contrast and saturation. Trial and error will allow you to find standard settings that work as a starting point, and all good software will allow you to save those settings.

6. In-camera image adjustments (mostly) have no effect
Aside from their effect on the embedded preview jpeg (see point 7., below), any in-camera image parameters you've set - including noise reduction and sharpening, for example - will only be recognised by your camera manufacturer's own raw conversion software. If you use third-party software it'll make a stab at setting the white balance (though the numbers may not match what you've set on the camera), but will otherwise use its own default settings.

7. The histogram sometimes lies
If you're using the histogram on your camera to tweak exposure (a subject I'll come back to another time), it's worth knowing that it's not displaying the data from your raw file. Instead, it shows a representation of pixel values in the preview jpeg embedded with the raw file (which is also the image that you're seeing on the camera's LCD). But the jpeg has been processed with white balance, sharpening and other adjustments set in the camera's menus, all of which can affect the histogram.

Bottom line: pay attention to what the histogram's telling you, but remember that it doesn't relate directly to the raw data you're recording. And set image adjustment parameters in your camera's menus (like sharpening, colour and tone) to 'off' or 'low' wherever possible.

Still here? If you haven't wandered off to another part of the web in sheer boredom by now, you should probably give raw a go. Once you've experienced the degree of control you have over your results you'll find it hard to go back to jpeg. It's rather like having your own darkroom. Except with far more control, a complete absence of noxious chemicals and no need to monopolise the bathroom for hours on end...

Comments

[Chris Ratcliff]

Good guide Seb! I always think of RAW as nothing more than a saftey net just in case things go awry.

Will have to give Bibble a go...

[Phillip Stasiw]

Another great burst of info! I too agree on RAW, Curves in CS2 work a treat, but the File sizes are such a pain, your cards fill up so quick!

[Seb Rogers]

Hi Phillip,

Maybe it's because I've come from a film background (36 shots per 'card'), but I've never had an issue with file sizes. I run 2Gb cards in my cameras, which give 120 shots in the D200 and 100 in the D2X. Given that good quality 2Gb cards can be had for around the £50 mark (and that external drive storage is less than £0.50/Gb), it's not that hard to deal with the extra space that raw demands (I can remember when the first 1Gb CF microdrives were launched... I seem to recall they were well over £500...)

The other thing that I do is edit as I shoot, time permitting. Some photographers think that deleting in-camera is more likely to result in corrupt card directories, but so long as you always re-format in-camera every time you put a new card in, I don't think you'll have any trouble (I haven't had a single card failure yet, at least).

[warhead]

It's a fallacy that the white balance cannot be tweaked in jpeg. You can alter the balance with the mid-tones dropper in levels. You can record and batch process your jpegs the same way as you would when processing Raw files into some form a magazine might want!

[Seb Rogers]

Up to a point, Geoff, but you're still working with just 8 bits in jpeg, whereas raw is 12 bits. Arguably you'd be hard pushed to see the difference in most circumstances, but the perfectionist in me likes to know that it's there anyway :)

[Mei]

RAW is so much better than jpeg in every way except file size.

Most people would get more benefit simeply shooting RAW ather than JPEG and learning how to process the results than they ever would from, say, a new camera.

[simon]

"Another is that, armed with a raw file, the photographer can effectively make whatever white balance and exposure changes they like without affecting the quality of the outcome. "

you can with the white balance, as this is purely a post processing option, whether done in camera or subseuently...

[Seb Rogers]

'you can with the white balance, as this is purely a post processing option, whether done in camera or subseuently...'

In practice this is mostly true. But clipped channels can show up any major white balance changes post-capture. Getting white balance and exposure right, or close to right, in camera can make a difference to the quality of the end result. Shunting pixel values around after the fact only works within the dynamic range limitations of the sensor.

If you don't believe me, go outside and shoot a landscape on a cloudy day so that the ground's correctly exposed and the sky is blown. Shoot every white balance option with the same exposure. Then bring the white balance back to daylight values in raw software. The sky will acquire a colour cast in the most extreme cases.

Like I said, raw is not the lazy option. It's the best option for getting it right, but that involves capturing the best possible data in the first place :)

[simon]

Seb,

are you saying the manufacturers are lying when they say the data is the raw capture from the sensor then ? If it were then whatever white balance selection you made would have no effect - unless that is, all RAW postprocessors treat the white balance profile included in the file in some unrecoverable way - I know the EXIF data contains a large block of data describing the white balance...

[Seb Rogers]

No, I'm saying that there are limitations to shunting pixel values around after the fact. White balance affects the outcome of processing the raw data off the sensor. If the captured data isn't optimised then big shifts in white balance can lead one or more channels to clip earlier than the others, causing colour casts in highlights. It's why some photographers use the uniWB technique (which I've not tried), which takes white balance processing out of the capture equation but gives you a file that looks damn odd until you shunt everything back into place.

[simon]

Ah, I see, so one of us has the wrong idea of what "RAW" is supposed to mean. I think raw means raw, numbers from the sensor pixels, you think it means those numbers after they've been processed to factor in the white balance ?

[Seb Rogers]

Simon,

I think we actually agree. We're just talking about slightly different things :)

Raw is, as you say, numbers from the sensor pixels. Each proprietary raw format also adds some tags relating to white balance etc. that allow raw processing software to spit out something that looks about right.

Clipped channels in particular can impact the results of applying white balance tags to the raw data at the highlight end. Doesn't make any difference if you apply that tag in camera or in software later. What does make a difference is the resulting colour balance in the highlights (and to some extent noise in the shadows) when the white balance has been shifted to resemble a mid-tone point that's close to 128, 128, 128 in terms of colour.

The point I'm trying to make is that there's no such thing as a free lunch when it comes to white balance. You can't necessarily expect to retrieve a raw file shot with the wrong white balance if you didn't make sure to get the exposure right at the time of capture. Since exposure choices are affected by white balance if you use the camera's histogram to tweak exposure, getting the white balance wrong can cause all kinds of problems later.

A bit of fiddling one way or t'other is fine. Shooting everything with (say) tungsten white balance and then correcting later isn't likely to look great unless the raw data you're working with is optimal - which means correct exposure.

Which is where I came in to start with. Yes, raw gives you more flexibility to retrieve bad exposure and white balance choices than jpeg. No, correcting in software later is NOT the same as recording the best possible raw data in the first place.

[simon]

Oh, I get you, using the wrong white balance might skew your exposure...

[Seb Rogers]

Yep. And, potentially, leave you with hard to resolve colour casts in highlights if you got the exposure badly enough wrong that you clipped channels....