Football has been at the heart of Sky's success story since it picked up the Premier League rights back in the early 1990s, so when it starts to look at the next generation of broadcast technology, it's only fitting that the beautiful game serves as the test bed.

Director Tony Mills has been the go-to guy for Sky's tech trials since it broadcast its first match. He's overseen the move from standard definition to HD and was at the helm for the first 3D games as well.

And now, it is Mills in the director's chair for the first live 4K Ultra HD tests - and anyone who thinks that he might be jaded about next-generation television by now would be entirely wrong.

Trials and tribulations

TechRadar was given behind-the-scenes access to Sky's live 4K trial as West Ham played Stoke, and we had the chance - via video link up - to interview Mills about the trials and tribulations of making the latest tech work for the world's most popular sport.

Lots of equipment that you won't find in the average electronics shop
Lots of equipment that you won't find in the average electronics shop

"When I saw the practice pictures it instantly hit me that this is really something quite special and that became more apparent as the game went on," says Mills when we ask him about the impact of 4K.

"We were picking out distinct features of people behind the play - it is so sharp and bright. It was a lot more noticeable than in the early days between SD and HD."

The narrative of the game

Trying to make 3D work for live sport was a tough test, with a whole new directing 'language' to be learned by directors, but Mills suggests that adapting to Ultra HD has been more straighforward - at least so far.

A 3D rig - heavier and harder to move around
A 3D rig - heavier and harder to move around

"I was responsible for testing when we first went HD and I also did Sky's 3D coverage when we first started testing that.

"We certainly had problems with 3D - we spent six months testing [and] we only had a couple of rigs to play with.

"We went up and down the country to various reserve games to see what could or couldn't be done, and as the number of cameras grew to four or five quite often we'd start with five and end up with three because a couple would break!

"With Ultra HD we have the four cameras and I expected certain issues to develop during the game but nothing did.

"As we settled on a style of covering the match, the pictures got better and better, and when we started to turn the cameras onto the crowd celebrations, we went: 'Wow, just look at the pictures.'

"You can see details of faces, you can see the smiles and get a real sense of the depth. It just looked really really good."

Sky's 4K test
Sky's 4K test - in an Osterley studio

One of the advantages of 4K cameras over 3D is portability, and the time saving compared to setting up with the dual picture system 3D relies on.

"With 3D, we set them up and they took a long time to line up, and then you left them. If you moved them six inches for some reason the whole lineup process had to start again. We learned that we had no flexibility to move them.

"Today [with UHD] we have a handheld camera that we shot an interview with. We unplugged it, rushed it down as it was about to happen and the pictures were all perfect.

"The camera's now ready to see the players walking out and within two minutes it will be back behind the goal. There's a lot more flexibility with Ultra HD cameras than there is with 3D."