There are two major new films concerning slavery in the US that will shortly be reaching British cinemas and they couldn't be more different. One is an earnest, high-minded and well-crafted costume drama and the other is directed by...Quentin Tarantino.

You simply couldn't imagine Tarantino making a film like Steven Spielberg's new film Lincoln. Spielberg, for his part, wouldn't have the chutzpah to make a spaghetti Western/exploitation movie quite as extreme as Tarantino's latest effort, Django Unchained. Even so, the two movies are set within a few years of each other and have obvious thematic overlaps. Lincoln takes place in 1865 as the then President Abraham Lincoln fights a bitter political battle to pass the Thirteenth Amendment to the US Constitution that would ban slavery. Django Unchained is set in 1858, as an escaped slave turned gunslinger (Jamie Foxx) and a European bounty hunter (Christoph Waltz) try to rescue the gunslinger's wife from a southern plantation.

As he approaches his 50th birthday, Tarantino is tackling a hugely contentious episode in US history and one that filmmakers have largely avoided since DW Griffith's The Birth Of A Nation (1915) with its underlying racism and notorious scenes celebrating the Ku Klux Klan. Tarantino being Tarantino, he is doing it in an utterly brazen fashion.

In interviews in the run up to the film's release, the director has been striking a typically contradictory note. On the one hand, he has suggested, shooting his first Western was a blast – so much fun that he doubted the Hollywood bosses would have let him get away with it if they knew how much fun he and his crew were having. On the other, he has insisted that he wanted to show the ugliness, brutality and “surrealism” that went hand in hand with slavery.

“I was always amazed so many Western films could get away with not dealing with slavery at all,” the director commented in a recent interview in Newsweek magazine . “Hollywood didn't want to deal with it because it was too ugly and too messy. But how can you ignore such a huge part of American history when telling a story in that time period? It made no sense.”

Lincoln (scripted by Tony Kushner) is full of sententious, brilliantly written speeches about human rights, democracy and the legislative process. Django Unchained is powered along by trash talk and Tarantino's familiar wisecracking, punning dialogue. It is one of the few Westerns with a black hero (Jamie Foxx.) In Lincoln, although the film is set in the middle of the Civil War, the reality of slavery is kept in the background. We see the corpses of the dead Union soldiers. Lincoln is shown visiting wounded soldiers suffering horrible disfigurements. The real conflict, though, is in the debating chamber as white politicians land rhetorical blows on one another. In Django, the violence is unrelenting. There are whippings, slaves wrestling one another to the death and dogs ripping slaves to pieces. The grotesquerie of a system in which white Southern aristocrats treat their slaves as chattels is made very evident. In Lincoln, there is a wise, folksy, cunning President (brilliantly played by Daniel Day-Lewis) who uses his knowledge of human nature to push through political change. In Django, justice is administered through guns in slow motion, Sergio Leone-style action sequences.

Tarantino researched his subject matter extensively. However, he has made it very clear that he had no interest in making a history movie with a “capital H” (as he told a BAFTA audience last week).

Back in 1997, when Tarantino directed Jackie Brown, Spike Lee attacked him for his excessive use of the “n-word”. “I want Quentin to know that all African-Americans do not think that word is trendy or slick,” Lee was quoted as saying by veteran showbiz journalist Army Archerd. The use of the “n-word” is even more frequent in Django than it was in Jackie Brown. The light-hearted moments when Klan members can't see out of their masks or Django leaps aboard his horse as if he is Roy Rogers on Trigger, sit uncomfortably next to the scenes of slaves being tortured and abused. Tarantino talks about the toxic legacy of slavery in one breath and his love of Sergio Corbucci's Django films the next. Then again, that is his way. In Inglourious Basterds (2009), he took an equally lurid and tongue-in-cheek approach to Hitler and the Holocaust.

There is a sadistic element to Tarantino that hasn't dissipated since Reservoir Dogs with its famously gory scene in which Michael Madsen cuts off a cop's ear as we listen to “Stuck In The Middle With You”. Django has a similar scene in which it looks as if one of the leading characters is about to be castrated. He likes to make revenge movies in which the heroes get their hands very bloody. His justification is that it was cinema as well as the spaghetti Westerns, blaxploitation and martial arts movies of the 1960s and 1970s, which were extremely violent too, rather than real life that formed his tastes when he was a movie geek, growing up in California and working in a video store.

His films are never simply pastiches of old genres either. He retains a flair for funny, self-reflexive dialogue. Whether it's Harvey Keitel in Reservoir Dogs or John Travolta in Pulp Fiction or, now, Leonardo DiCaprio as the debonair young plantation owner in Django, he also excels in coaxing surprising performances from well-known actors in unfamiliar roles.

Tarantino has intimated that he would like to make more Westerns or perhaps try his hand at a 1930s-set gangster movie. Some critics are calling on him to “grow up” now that he is nearly 50. His fans, of course, hope for the reverse. It is instructive to compare his career with that of Steven Spielberg, who made genre movies like Duel and Jaws early in his career before going on to direct such weighty and mature efforts as Schindler's List, Amistad and now Lincoln. If you took the juvenile movie-brat enthusiasm out of Tarantino and got him making straight historical epics, he would be a pale shadow of the filmmaker that he still is. He is still a rogue Peter Pan figure, operating as profitably as ever in the illicit margins between arthouse and exploitation.

'Django Unchained' is released on 18 January. 'Lincoln' is released on 25 January