On any decent dSLR camera you can set a custom white balance to neutralise the colours under different lighting circumstances. Every dSLR brand comes with its own methodology and approach to neutralising the camera, but they all share in common that the colour temperature can be compensated for by taking a snapshot of a grey object as its foundation. Some high-end cameras such as the Nikon D2X and the Sony Alpha 700 approach neutralisation with a finer, more granular attitude. They also allow you to set up a digital colour compensation filter. 

This tutorial has a very brief overview of White Balance and Colour Compensation, and an explanation why I am now using the Sony Alpha 700 as my preferred dSLR camera not just for fun photographing, but also for commercial photography (e.g. shooting products). Finally, it teaches you how to set a custom white balance with the Nikon D2X and the Sony Alpha 700.

White Balance is a term that comes from the film and video camera industry. For a still camera like a dSLR, the term Grey Balance would be more suitable. However, everybody is using the term White Balance, and therefore so shall I. Still, let me quickly explain why grey balance is more accurate: to neutralise a dSLR you don’t use a white reflective surface. Instead, you use a slightly grey reflective surface (some 16% grey, actually). That’s why grey balancing would be more accurate.

Every type of light has a colour cast. The most obvious is the fluorescent greenish cast that makes flesh tones look absurdly unhealthy. The human eye can compensate for the greenish cast up to a point --it does a decent job-- because our brain has some idea of what flesh should look like. The brain compensates for the light’s colour cast in the process. The camera doesn’t have that kind of a brain, and so it just records what it “sees”: a green flesh tone.

We can compensate for this by neutralising the camera --setting its grey point or white balance-- in relation to the light conditions that we present it with. This means that you can let it “see” a grey card and tell it this is neutral grey, so it can internally compensate for colour casts. The result with a medium end digital SLR camera is an adjustment to the grey balance without the user knowing what exactly has been corrected.

However, there are two ratios in neutralising a SLR camera for colour temperature. The first is the ratio of the colour intensity of blue to red, and the second one is the relative amount of green (the green-magenta balance). High-end dSLRs such as the Nikon D2X and higher, the Canon EOS 1D and 5D, and the Sony Alpha 700 will compensate for both ratios and enable you to at least see the compensation amount for each ratio individually.

These high-end cameras also allow you to set each ratio by itself. In the Sony Alpha 700, the green-magenta ratio has 18 steps (not including the neutral step) from G9 (green 9) to M9 (Magenta 9). The below table shows you how far apart each step is in Tint value as measured in Adobe Lightroom. An accurate way to determine each step would be to measure the output in mireds (the hyperlinked page is the best explanation of colour balancing and the term “mired” that I’ve found), but that’s beyond this tutorial (and frankly, also beyond my means in terms of equipment needed).

Why The Sony Alpha 700

The Sony Alpha 700 won an Editor’s Award and a Golden Cube for various reasons. The first and most important reason to me is that it can be used with (at the time of this writing) three Zeiss lenses. There are the 135 mm and 85 mm Zeiss lenses and there is the 16-80 mm Zeiss zoom lens. I had the pleasure of testing two of these lenses earlier in 2007, and I was particularly impressed with the f1.4 Planar 85mm which has a circular aperture ring for a beautiful defocused effect (the so-called bokeh).

Zeiss lenses are the absolute top, and the Planar was no exception. It was razor-sharp and its resolution was incredibly high. The availability of Zeiss lenses is my most important reason for using a Sony Alpha, as these are the only digital SLR cameras that I know of that support them. If you want Zeiss lens support beyond the Alpha 100 or 700, you will have to dig up the price of a small Mercedes and buy a Sinar, Hasselblad or equivalent medium-size camera.

The second reason that I chose the Alpha 700 above a Canon or Nikon is that it is quite inexpensive when compared to these two other brands. Equivalent Canon and Nikon models are typically some 200 to 400 Euros more expensive --and they don’t come with the Zeiss support.

The third reason is the build of this camera. The Sony Alpha 700 is a semi-professional camera worth the name. It has features --such as the one we’re discussing here-- that are only available on cameras that are used by professionals. It has an aluminium alloy chassis and a magnesium body for strength and ruggedness, but it is surprisingly light-weight.

There are plenty of other reasons why I chose the Alpha 700, but those are the main ones. The only thing that stands between this camera and the “full pro” denomination is the absence of a full-frame sensor. Personally, and given the results you can achieve with it, I don’t mind, but professionals probably would.

With regards to White Balance, the Alpha 700 offers full control over neutralisation, just as the professional Nikon and Canon models.