Sun 27-Oct-13 01:23 PM | edited Sun 27-Oct-13 01:34 PM by Gromit44
Mine does the same - the viewfinder indicator only shows AE-L even when the button is assigned to lock both exposure and focus (i.e. f6 is set to AE/AF Lock).
This is because there isn't a separate AF-L indicator lamp in the viewfinder (not enough room for two lamps?) - so the AE-L lamp doubles for both AE lock and AF lock.
You can test this by allowing the shutter to focus (i.e. set a4 to Shutter/AF-ON). Now focus on something with the shutter button, then press and hold down the AE-L/AF-L button (the AE-L indicator lights up). Keep holding it, recompose on a different subject and half-press the shutter button again - you'll find that the camera will not refocus, so focus is locked until you let go of the AE-L/AF-L button. Exposure is also locked until you let go (the aperture & speed readout stays the same as long as the button is held).