[yelvertoft]

Ok, you’ve got your dSLR or pro-sumer camera, you’ve been playing around with it for a while and are getting pretty confident. You keep hearing people on the forums making bold statements like “Raw capture is the only way to use your camera, you cannot call yourself a serious photographer unless you use raw.”

So how much of this is true? It depends very much on what kind of photography you like to do and more importantly, how you like to view and use the resulting images. Let’s begin by outlining some benefits and disadvantages of using raw capture mode. There’s more to it than I’ve outlined below but lets just stick to the basics with this article.

The Advantages:
· You can correct a variety of errors, such as setting the incorrect white balance or exposure compensation, that you may have made at the time you took the picture. The scope and extent of correction is greater than you could get away with by post-processing in JPEG.
· The fine detail captured in the image is preserved with the maximum possible clarity.

The Disadvantages:
· Raw capture takes up a lot more space on the memory card, you can’t take as many pictures before the card is full.
· Raw images require processing before they can be viewed or printed by “standard” applications. This takes time and effort.

What is raw capture?
Raw is not an acronym (for once), raw means unprocessed. The sensor captures the image data and files it away without the camera using any of the settings normally applied during JPEG processing such as white balance adjustment, contrast adjustment, saturation adjustment, etc. What light hit the sensor is filed away “as is”.

So when should you use raw mode?
· If you are demand the very highest level of detail in your images, you may be doing fairly severe image crops that require this level of detail.
· If you are a professional or wish to regularly sell your images as a bit of extra cash. If this is the case you probably don’t need to read this article anyway.
· If you wish to print your images at bigger sizes than A4 (roughly 12”x8”).

When isn’t it so important to use raw mode?
· If you are taking ‘snapshots’, pictures that you have just grabbed for yourself, a quick snap of a moment in time.
· If you only intend viewing your pictures on a small/medium sized monitor.
· If you don’t intend to print your images any bigger than A4.

Having got a load of pictures in raw mode, what do you do now? You need to process them before they can be viewed or printed using standard applications. I will try and explain the basics of this processing using Adobe Camera Raw (henceforth referred to as ACR). This is a free plug-in that works with Photoshop Elements 3 or 4, or Photoshop 7.0/CS/CS2 for that matter if you have it (though not all versions of ACR are compatible with 7.0 or CS). Another popular free application for raw processing is Raw Shooter Essentials. If it is capable of raw capture then your camera will have come bundled with a piece of software to enable you to process the raw files. The basics I am trying to explain below will hopefully be similar to the options available in your processing package.

On loading your raw image file into ACR, you will be presented with a screen showing the image on the left and a histogram with a bunch of sliders and pull-downs for adjustment on the right. The histogram shows the darkest and brightest points in an image. The horizontal axis represents the brightness and the vertical axis represents the number of pixels present in the image at that particular brightness. The histogram should be watched closely during all the adjustments to see what is happening to the picture as you edit.

To begin, adjust the White Balance
There is a pull-down box available which will hopefully list the presets available in your camera’s menu. If the version of ACR you are using does not support the camera you are using this may not be the case. You can select from the pull down list, the setting that matches the lighting conditions the picture was taken in. This is a good starting point. You can make further adjustments to the white balance settings, if required, using the two sliders available. These are labelled Temperature and Tint. The temperature slider controls the yellow/blue balance of the picture making the image look warmer or cooler, the tint slider controls the magenta/green balance and is useful for fine tuning. You can make quite dramatic changes to the overall feel and atmosphere of the picture by simply changing these two sliders.

Next stage, Exposure, Shadows, Brightness, and Contrast.
The Exposure, Shadows, Brightness, and Contrast controls let you shape the overall tonality of the image.
The exposure control sets the white point in the image.
The shadows control sets the black point in the image.
The brightness control adjusts the midtone in the image and the contrast increases contrast around the midtone set by brightness. That sounds a lot more complicated than it really is. The best thing you can do is play with an image yourself and see what the effects are. Keep a careful eye on the histogram whilst tweaking, it’ll teach you a lot about what’s happening to the image. Whilst using the exposure and shadows sliders, ACR allows you to view the extent of “clipping” in the image. Clipping is where you are “whiter than white”, the pixels have maxed out and cannot get any brighter. This allows you to see where you are sacrificing detail because of the adjustments you are making. To get the clipping display, hold the Alt key whilst moving the exposure and shadow sliders.

Saturation control
As with the saturation control in your normal image editing program, the saturation control the saturation of colours in the image. Personally I never touch this control in ACR, I prefer to adjust the saturation in Photoshop, you can tweak if you wish.

Output the image
At the bottom of the ACR box, there are settings used to change the way that your raw image is to be output. The Depth drop-down box allows you to choose either 8 Bits/Channel or 16 Bits/Channel. 16 Bits/Channel provides the maximum amount of information in the final file. Immediately converting the image to 8-bit at this stage will remove much of the benefit of capturing in RAW mode to begin with. You may have to convert to 8-bit depth later on if you take your prints elsewhere to get them printed as some machines are not setup to read the 16-bit file formats.

Having output the image from your raw processing tool you will then have an image in a file format that can (hopefully) be read by a standard image editing application. Your raw processing will have hopefully done a lot of the work that you would otherwise have done on a JPEG file when using that capture mode on the camera. There is nothing to stop you carrying on and editing the image using your standard package once you’ve got this far.

Other settings
There are plenty of other settings that can be tweaked in ACR, and no doubt in other raw processing tools too. The purpose of this article is to get people up to speed on the basics of raw processing, not an exhaustive tutorial. If anyone wishes to put together an “Advanced Raw Processing” tutorial then please feel free to contribute by starting a new thread.

I hope this is of help to someone.

Regards,

Duncan.