By Emma Saunders
Entertainment reporter, BBC News
Clash of the Titans was at the top of the UK box office for two weeks
Avatar, Clash of the Titans and the upcoming Tintin trilogy - all of them big budget movies made in 3D.
But it's not quite as straightforward as that.
The price you pay to watch a 3D movie at the cinema is always the same - but there are several ways of tricking your eyes into seeing that extra dimension and, according to some, the quality varies greatly.
Avatar, for example, was filmed entirely using a 3D camera system, which was partly developed by director James Cameron.
Other movies, including the forthcoming Harry Potter finale, are being shot with regular cameras and converted into 3D during post-production.
Clash Of The Titans director Louis Leterrier had wanted to use 3D cameras to shoot his Greek mythology epic - but the technology was so new, the only ones in existence had already been booked for Avatar.
Leterrier had reservations about the conversion process - which, in essence, cuts the picture into layers like a pop-up book - but ultimately, he was impressed with the result.
"It was absolutely amazing, just the amount of detail. It doesn't look like cut-out people on flat backgrounds - everything was absolutely realistic," he told BBC 5 Live.
But not everyone agrees.
Film critic Roger Ebert enjoyed the film but ended his review in the Chicago-Sun Times with a warning: "Explain to kids that the movie was not filmed in 3D and is only being shown in 3D in order to charge you an extra $5 a ticket.
"I saw it in 2D, and let me tell you, it looked terrific."
The Daily Telegraph reviewer Sukadev Sandhu was also unimpressed.
"Part of the problem lies in transferring it to 3D," he wrote.
"Avatar raised the bar quite high for that format... here it feels random, superfluous, distinctly unspectacular. If you choose to take off your specs you'll be missing very little."
Martin Hobbs of Prime Focus, the company which converted Clash of the Titans, says he was pleased with the outcome although admits it was converted quickly.
"There are shots that could have been done with a bit more time," he concedes.
"You need time to make a refined product."
Hi-tech effects were used to create Avatar's eye-popping visuals
The film was converted in just eight weeks as opposed to the usual 12 - 15 weeks because making it into a 3D movie was "an afterthought", Hobbs explains.
To get the film ready in time, Prime Focus employees endured lots of overtime and director LeTerrier was very hands-on.
"He was completely involved, sometimes here up to three times a day," says Hobbs.
Hobbs is keen to point out he is not against making films in 3D - far from it.
"It's not about one (process) or the other - you could shoot one scene in stereo and then choose to convert another one."
But Avatar director James Cameron has also hit out at the conversion process.
Cameron said filming a movie in 3D assures better quality over the subsequent conversion.
Nonetheless, the film-maker has revealed he wants to remake his 1997 blockbuster Titanic in 3D, but said it will be different because he plans to take his time instead of doing a "slapdash conversion".
Tim Burton, whose Alice in Wonderland movie was converted to 3D in post-production, believes the differences in quality are more about artistic vision than techniques.
Jackson describes 3D images as "a little dull".
"With all of these tools, you can see good 3D, bad 3D, good conversion and bad conversions," he said.
But not all film-makers are keen to jump on the 3D bandwagon.
British director Mike Newell (Harry Potter and the Goblet Of Fire, Four Weddings And A Funeral) filmed the bulk of his new movie, Prince Of Persia, in 2008 and some critics have expressed surprise that it was not given a 3D makeover on its journey to the big screen.
But he was adamant that the film would be seen the way it was shot.
"If you're going to do a 3D conversion, what you have to do at this stage is to send it off to some bloke's garage in South Korea and he'll give it back to you in three months' time and say 'that's your lot," he told the BBC.
"Nobody's prepared to do that".
Referring to his fellow colleague Cameron, he added: "Sequences in Avatar, like the seeds falling like snow, have to be planned from the very beginning. You can't just run it through a conversion process. Until Avatar was released, nobody knew."
Another hold-out is Pan's Labyrinth director Guillermo Del Toro, who plans to make The Hobbit in 2D, according to producer Peter Jackson.
"Guillermo wants to shoot in 35mm, old-fashioned film," Jackson has said, "which suits me, because he wants to keep it in the same space as the original [Lord Of The Rings] trilogy".
Jackson has been keen not to over-emphasise the vogue for 3D, saying it "only adds to the experience" of watching a movie.
"The only thing I get annoyed about is the image being a little dull. It does feel like you're looking at the movie with sunglasses on."
Indeed, that is probably the main downside for the viewer. The polarization process that creates the illusion of 3D results in a darker image on the screen, making films less vibrant.
But for just a few million dollars, a small percentage in a blockbuster budget, 2D films can be converted to 3D quite easily.
It is cheaper to convert than make in stereo - to make a film in 3D roughly adds about 30% to the budget, but the cost of conversion is unlikely to exceed $15m (£9.8m) dollars.
And with the extra bucks to be made at the box office, 3D movies show no signs of stopping.