My Little Eye (18) <br></br>One Hour Photo (15)

Ghosts in the machine - and killers

A group of deluded young men and women convince themselves that it would be a good idea to spend some time in a strange house. So what if there's someone watching them, they can handle it. Suddenly, one of them disappears, followed by others – until a lone survivor makes a bid for freedom...

The makers of Big Brother and Survivor seem to know their haunted house films down to the last badly maintained floorboard. My Little Eye repays the compliment, even if backhandedly. Five twentysomething Americans have answered an ad on the internet to spend six months in a remote, forbidding heap. There, they will be the subject of a "reality webcast" – the collective prize is $1m, but if one of them leaves the property before the six months are up, all five of them forfeit the money.

Director Marc Evans's big idea is that you have logged on to watch the webcast. We observe and hear events through cameras and microphones dotted around the house, most (though not all) visible to the house-mates. The wobbly camera-work, the poor lighting, the clumsy scene stealing and dull pillow talk – each ramshackle detail of the reality show is rolled out. Even when, instead of food parcels, weapons and threatening messages start arriving for them, these Big Brother-literate house-mates may be spooked but they won't be fooled – they know it's only the producers trying to spice things up. Isn't it?

It's possible to argue that Evans's third film is too clever by half. (His last feature, Resurrection Man, was a bizarre attempt to stage a slasher film against the background of the Troubles in Seventies Belfast.) But at least he swings a large shiny axe at the smirking self-regard of the likes of Scream. Call it old-fashioned, but My Little Eye wants to scare its audience, not flatter their horror film general knowledge. And it succeeds, for a while, thanks to its technical virtues. The night-vision camera, for instance, is a familiar device (one scene is virtually a rerun of the The Silence of the Lambs' murky green conclusion) but a creepy one, nonetheless. Better still is the sound design – conversations, one minute loud, the next barely audible, are contrasted with the noisy workings of the compound, all "picked up" by the mics. This is a house, you're constantly reminded, that is haunted by technology.

That's as far as Evans takes the webcast conceit. In fact, it's to The Blair Witch Project rather than the world wide web that the film owes much of its low-fi tension. Otherwise, it's conventionally edited, and takes place only over the last few days of the house-mates' six-month imprisonment. There are sound reasons for this – if you watched the Big Brother continuous webcasts, you'll know there are some terrors that should remain on the digital editing suite floor.

But it's a pity that Evans didn't explore other features of internet broadcasting – the multiple perspectives that multiple cameras allow, for instance. All we get, briefly, is a four-way split screen at the film's start and its end, and that's more a stylistic flourish than narrative experimentation.

But, for a good hour, this tense little "websploitation" movie works well. At one point, the script – which has already cast the audience in the uneasy role of internet voyeurs – reveals that those watching the webcast have a bloodthirsty financial stake in the goings-on of the house. It's a chilling and clever moment, questioning both our motives as viewers and the motives of those who profit from our thirst for this kind of entertainment. (Another good joke is that those behind the webcast turn out to be a couple of dotcom dudes, high on some pretty dirty venture capital money.) The plot, too, moves up a gear – we know heads are going to roll, but not in which direction.

Sadly, it's also the point at which the film goes axe-happy. Over the final 20 minutes, things get worse and worse for the house-mates – and I don't mean that they have to use an outdoor shower or sing a song to earn their dinner. Evans has a salient comment to make about the risibly upbeat and cathartic conclusion of most American horror films, but it's lost in a welter of cartoon gore.

One Hour Photo also wonders about how we consume images. But this Robin Williams vehicle is as buffed and glossy as My Little Eye is scored and scratched. That's because Mark Romanek's feature film debut puts itself in the shoes of Sy Parrish (Robin Williams), who runs the photo counter at the local discount supermarket.

Sy's developing machine is the best-calibrated in the county. What that means for his customers is perfect prints; what that has come to mean for the lonely Sy is a pathological desire for the domestic bliss beaming from a colour 5x8 family snap. In particular, Sy has attached himself to the Yorkins, a seemingly happy young family. So much so, that he likes to think of himself as a silent uncle to their son, Jakob, decorating his house with copies of the Yorkin family pictures since Jakob was born. The sign in Sy's back office says it all: "Our customers are everything: without them, nothing else matters."

And so Robin Williams continues in his apparent rehabilitation as a serious actor. Death to Smoochy is yet to be released here, but we've already seen him in Insomnia, and his campaign for credibility drags on with this laboured psycho-drama. Unfortunately, there's still not much to go on. It's not that he can't do "disturbed loner" – Mindy appeared more like Mork's social worker than his friend, after all. It's that, uncharacteristically, Williams submits meekly to poorly written parts, in both this and Christopher Nolan's disappointingly workmanlike thriller.

At times, One Hour Photo feels like a lighting exercise to which someone has belatedly hitched a script. Romanek, previously a pop-promo maker, wrote as well as directed. But he leans heavily on the cinematography and production design to dramatise what Sy sees as the gulf between his life and the Yorkins'. Theirs is full of oaky, warm hues and welcoming textures; his is dominated by stark colours and unyielding surfaces. (Sy's hair is blond, which gives Williams the unfortunate appearance of a middle-aged Paul Gascoigne.) You might call the result an overexposure, and one in which Sy's and the Yorkins' characters all but fade away.

Along the way, Romanek makes the point that photographs aren't to be trusted – the stable family life portrayed in the Yorkins' photographs isn't a truthful reflection, a realisation that tips Sy over the edge. Unfortunately, Romanek makes that same point again and again, draining the script of whatever drama it might have had. The film's title nearly gets it right – but it's more like two hours.

Jonathan Romney returns next week