In C++ multithreading applications, should I pass lambda or function with parameters?

I have just started learning about multithreading in C++... is there a difference between t1 and t2?

#include <iostream>
#include <thread>
#include <mutex>

std::mutex mutexCout;

//prints the value of x, and then increments it
//param: int value to display and increment
void foo (int& x)
{
    std::lock_guard<std::mutex> guard_(mutexCout);
    std::cout << "x is " << x << "\n";
    ++x;
}

//testing different ways to call a function with reference
int main() 
{
    int x = 5;
    //is t1 different from t2???
    std::thread t1 ([&] {foo(x)};
    std::thread t2 (foo, std::ref(x));
    {
        std::lock_guard<std::mutex> guard_(mutexCout);
        std::cout << "x is " << x << "\n";
    }

    return 0;
}