Schumacher returned to the sport in 2010 for three seasons, claiming a sole podium in Valencia last year.
When asked whether the competition was greater than in his first career, Schumacher replied "Yes, because the field is closer together".
Speaking to German publication Auto Motor und Sport, Schumacher added "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 also added that while the competitive field does not mean the current crop of drivers are the best, he reckons they are the most professional.
"Are the drivers of today so much better? It has always only been the best drivers who are in Formula One. Today are there are more 'best' drivers? Of course I set new standards with the way I work, but my former colleagues were on the way [where] 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".