Questions on exposure compensation

[red_ryder]

By changing the shutter speed from 1/125 to 1/250 I am reducing the EV by 1 stop right? Similarly by increasing the aperture from f2.8 to f4, I am reducing the EV by 1 stop.

So when I use the exposure compensation button on the camera and reduce EV by 1/3 stop, what actually happens? If there is no shutter speed in-between 1/125 and 1/250 how does the camera do a 1/3 reduction? Does it still keep my aperture and shutter speed settings?

 

[jnet6]

depending on which mode you are in. A mode or S mode.
EV does not have any effect when you are in manual mode(M mode)

eg. A mode, normal reading is F2.8 @ s=1/125.
+1ev F2.8 @ s= 1/60.

S mode, normal reading is s=1/125 @ F5.6
+1ev s=1/125 @F4

 

[MDZ2]

If you are using an SLR, most lens support aperture adjustment up to 1/3 stop. Also, the shutter speed can vary between 1/2 and 1/3 stops. Take a look at the indications the next time you take a picture. If you set the camera to aperture priority, you will see funny in between shutter speeds when you set the ev at 1/3 stops.
For compacts with fixed aperture plates, most probably the ev only controls the shutter speed.

 

[jumbocrab]

By changing the shutter speed from 1/125 to 1/250 I am reducing the EV by 1 stop right? Similarly by increasing the aperture from f2.8 to f4, I am reducing the EV by 1 stop.

So when I use the exposure compensation button on the camera and reduce EV by 1/3 stop, what actually happens? If there is no shutter speed in-between 1/125 and 1/250 how does the camera do a 1/3 reduction? Does it still keep my aperture and shutter speed settings?

Are you using a modern DSLR camera? If yes, then most likely your camera will be capable of selecting 1/3 stops in between 1/125 and 1/250 - the norms are 1/125, then 1/160, then 1/200, then 1/250.