One of the web's "25 most influential people" says that camera phones will soon make digital SLRs obsolete.

"There will be no need to carry around those heavy lenses," Nokia's marketing EVP Anssi Vanjoki told a gathering in Helsinki, according to Reuters.

Citing continuing improvements in cameraphone technology, Vanjoki said: "They will in the very near future revolutionise the market for system cameras." And he wasn't Vanjoking. Do remember, however, that Nokia doesn't make and sell DSLRs, they make and sell phones.

There are three major components to digital photography: the image sensor, the lens, and the hardware-software processing component. In each of these areas, DSLRs have essentially insurmountable advantages for the foreseeable future.

And you notice that megapixelage is not on that list. Perhaps the most overrated spec in cameraland, the sheer number of pixels that a camera claims does have an impact on the size of the image you get to play with, but how those pixels are captured matters far more to image quality.

And those pixels are captured by an image sensor. A good rule of thumb is that the larger the sensor, the less noise in the image. The CMOS sensor in a prosumer-level Nikon D90, for example, is 15.8 by 23.6mm, and the sensor in a pro-level Canon EOS-1Ds Mark III is 36 by 24mm. Fitting a sensor of that size into a Nokia cameraphone wouldn't only be difficult space-wise, but achieving the necessary lens-to-focal plane distance in a pocketable device would result in one frightfully lumpy pocket.

A lens doesn't only let in light - in most cases, the more the merrier - it also carefully collimates that light, adjusts for chromatic aberration, and ensures that no geometric image distortions occur at varying zoom lengths. Until the laws of physics change, you're not going to get quality zoomable lenses into a thin, tiny device.

And let's not even talk about "digital zoom," which even a rank amateur photographer soon discovers is a cruel pixelating joke.

We'll pass over the the hardware-software processing component of a DSLR versus a camera phone for now, seeing as how most pro photographers - unless they're on a heinous deadline - prefer to shoot in raw mode. When "shooting raw," pure pixel data is read from the image sensor and stored on the memory card, to be retrieved later and manipulated by a far more-powerful PC or Mac with dedicated image-editing software.

While OmniVision has announced a 6.35mm, 5-megapixel raw CMOS image sensor, the OV5647, the overwhelming majority - if not all - current cameraphones provide images in compressed JPEG format, despite some kludges being available.

JPEG images are plenty good for snapshooting and even advanced amateur photography, but if you want total control over such image niceties as white balance, effective exposure, fill light, lens corrections, and the like, raw is the way to go.

And if you want raw, you want a DSLR - or, at minimum a high-end pocket camera such as the Canon PowerShot G11. You don't want a cameraphone.

Vanjoki was, however, accurate in one of his Helsinki comments: "It will not take long, less than a year, when phones can record HD quality video and you can transfer it directly to your HD television set." With small-sensor pixel counts increasing and the power required to operate them decreasing, he may very well be correct.

It will, however, be crappy-looking HD video. ®