Michael Schumacher admits that the level of competition in F1 is now much greater than in his title-winning years - with the field being much closer than when he was dominating the sport.

Schumacher called time on his career for a second time at the end of the 2012 season having come out of retirement for a three-year stint with Mercedes, which yielded just a single podium finish in Valencia last year.

While some of that relative lack of success was down to the fact that he was no longer at the wheel of a car that was the class of the field, the seven-time champion insisted that the increased competition had also played a role.

"The field is closer together," he told Auto Motor und Sport. "In my early days, there was always the chance to be quicker than another driver not just by a couple of tenths, but a full second. Why? Because the cars aerodynamically were not so balanced and were therefore very sharp to drive. As a driver, you then had many more possibilities yourself.

"Today, the cars are aerodynamically stable and well balanced; the window in which you work is not as big."

Schumacher added however that the closer competition didn't automatically mean that the drivers were better now than they had been in the past.

"Are the drivers of today so much better?" he said. "It has always only been the best drivers who are in Formula One. Today there are more best drivers? Of course I set new standards with the way I work, but my former colleagues were on the way they were accustomed to working perfectly, and some had to replicate the new standard. The difference today is that maybe the new generation has grown up with this same scale."