Flash exposure compensation with the MR-14EX can be set up to +/- 3 stops in 1/3-stop increments (or 1/ 2 -stop increments with some cameras). You can also use flash compensation in combination with normal exposure compensation (to control the background's exposure level) in a flash picture.
This QuickGuide reviews how to use either of Canon’s Two Macro Speedlites: the MR-14EX and MT-24EX. The primary difference is between them is that the MR-14EX has two circular flash tubes permanently mounted opposite each other onto the Flash Ring, while the MT-24EX has two removable and adjustable flash heads that snap into miniature flash shoes.
In low-light or when the viewfinder image gets darker at high magnification, it becomes difficult to achieve correct focus. In such cases, the focusing lamp can assist with focusing.
Three bracketed flash shots can be taken: Correct exposure, decreased exposure and increased exposure. The three shots can be bracketed up to +/-3 stops in 1/3-stop increments (1/ 2 -stop increments if the camera enables only 1/ 2 -stop increments). This is called FEB (Flash Exposure Bracketing).