When the Nikon D90 arrived, the buzzword was, of course, HD video recording. Nikon claimed a world first with its new baby’s 720p record mode, and also added an HDMI socket, so that snappers, or indeed videographers, could connect up their camera to an HD ready TV. Canon has now upped the stakes with the EOS 5D Mark II, which boasts full 1080p captures at 30fps.

There’s been lots of talk online about why we are getting HD capabilities in DSLRs now. After all, we’ve had HD shooting abilities in digital compact cameras for a while now, the Panasonic Lumix DMC-FX35, to name but one, was launched way back in February.

Well – it’s all to do with processing abilities – namely how quickly the camera can deal with data. For digital stills, however fast the capture rate is of the DSLR, it still has a "break" in-between shots, whereas HD video requires constant processing – something the new Canon DIGIC 4 and the Nikon Expeed chips are capable of.

Then there’s the sensor – Canon has always used CMOS sensors in its DSLRs (bar one CCD sensor), whilst Nikon moved to CMOS technology for the D90, where as its predecessor, the D80, used a CCD sensor.

It is generally agreed that CMOS sensors are more power efficient, better on noise and handle heat better than CCD sensors hence why they are now being used in the two HD video capable DSLRs.

But, all of this aside, do we actually need, or want, HD capabilities in DSLR cameras?

For compact cameras, there is certainly a huge appeal, after all, think where people usually take pictures – parties, sport events, and family gatherings. For all of these, being able to shoot short videos to be able to show others, or load up online, is great.

To be honest, whether the video is HD or not probably doesn’t matter to many people unless they have invested in an HD ready TV, and then having the higher quality filming option on their camera is worth forking out for because it will show up in the standard of the footage they play on the TV.

Moving on to the D90, there was some grumbling about the fact that the HD video recording was restricted to five minutes, and also the video mode doesn't offer auto focus or auto exposure. These aren’t factors that would bother digital compact owners, but, if you are paying £699.99 for a camera, you are going to be a bit more demanding. After all, for that money, you could buy a HD capable digital compact and a HD camcorder.

But, in reality, the majority of people who will buy the D90 will do so for its image capture abilities. As its price reflects, this isn’t a model for people who only take their camera with them to parties, but people who love photography, and, whether it is their livelihood or not, are discerning and want a fast, responsive machine that will deliver crisp, impressive shots. For them, the video capabilities are a nice extra, but only if none of the still shooting capabilities have been sacrificed to add HD video.

So now to the Canon EOS 5D Mark II. With its £2299 price tag, this model is three times as expensive as the D90, and as such, despite what Canon says, will be appealing to a largely pro audience.

There has been much talk amongst journalists about how photographers need to learn to capture film as well as stills in order to survive in this increasing tough market, when magazine budgets in particular are being slashed. But is the quality delivered by the new 5D model going to be good enough to produce footage that can be sold alongside the top quality images this camera will no doubt deliver?

Digital camcorder manufacturers should be concerned about the D90 because it is just cheap enough to appeal to the mass market and, as such, it could definitely eat into their sales as HD video producing digital compacts have. And there are sure to be a whole host more digi compacts, bridge models and DSLRs under £1000, offering HD capabilities soon.

But, for the top end of the market, for those with wallets big enough to buy the 5D Mark II, or those who need this snapper for work, the video recording capabilities are simply a nice extra.