In the previous installment, we looked at ACR3, which is Adobe's Converter for Raw files. ACR3 is so great that it's well worth upgrading the package just to get those new Raw workflow features. But today, we'll move to the main Photoshop program, which contains a number of new features of specific interest to digital photographers.

Click here for a look at how Photoshop CS2 improves handling in the Raw format.

The new filters that stand out most at first glance are Smart Sharpen, Reduce Noise and Lens Correction. We'll have a quick look at the first two today, and keep the Lens Correction tool for later.

In digital photography, sharpening is a bread-and butter matter. It's a novelty to photographers coming from film, but it's inescapable in digital. The need arises principally from the softening anti-alias filter covering the sensor of almost every digital camera.

Furthermore, digital printing tends to soften detail yet again, which is why shots are usually sharpened somewhat at some point in every digital workflow.

Photoshop's main tool for sharpening so far has been the USM (Unsharp Mask) tool, with a slider-driven interface that is as obfuscating as its name.

CS2 brings us a new Smart Sharpen filter, which adds to but does not displace the old Unsharp Mask workhorse. Smart Sharpen offers some new abilities—it can reduce Gaussian blur, lens blur or motion blur.

For motion blur, you need to tell the software the direction and the amount (in pixels) of the displacement for which you wish to compensate. The result seems to be a sharpening effect with no halo, unlike anything you could get with USM.

It would seem that the new Smart Sharpen filter hides under an assumed name. It is in fact an unshaking and deblurring tool!

There is some sophisticated technology lurking under this simple interface. In fact, while adding blur is easy, some rather hairy mathematical code is necessary to achieve its removal. This type of effect goes under the recondite name of deconvolution.

Adobe should be more honest and call the thing a deconvolver, or is it afraid of falling under technology export restrictions ?

Can Adobe redefine the creative workflow? Click here for a column.

Now that we've dealt with Smart Sharpen, we can move to the second part of this sneak peek, namely noise reduction. Unfortunately, Adobe does not seem to have gone all out on this one.

The new Reduce Noise filter is very much a special-purpose tool, but for Hi-ISO shooters needing to treat shots aggressively, it can be an essential one.

A number of excellent, third-party plug-ins out there—such as NeatImage and NoiseNinja, and even Kodak's Digital Gem—cater to this market and have built up an audience.

The Reduce Noise filter has an intriguing "Remove JPEG Artifact" check box, which may be useful for prepress treatment of compressed photos, and it comes with its own "Sharpen Details" slider that, judging by the halos, seems to invoke USM to restore detail that has been oversoftened by the noise-reduction algorithm.

While CS2's inclusion of a new, "free" filter is a welcome step in the right direction, I don't think the third-party developers will need to rush out and find new jobs. We will see how shooters judge this feature when CS2 hits the street.

For myself, I think the main practical application of this ostensibly noise-reducing tool may be that of a sharpener that doesn't add noise and intensify grain when a picture gets sharpened!

Some tools are at their most useful when they are misused.

Edmund Ronald has a Ph.D. in Applied Mathematics, but he is currently on a sabbatical as a photographer in Paris.