All of the D5100's settings to customise operation to your personal preferences.
ou can prevent the D5100 from constantly adjusting the exposure to a changed image frame when the shutter release button is pressed. Instead, it will activate the exposure lock as soon as and as long as you press the shutter button. You can arrange for this in the custom settings menu
You can shift the start of autofocus from tapping the shutter release button to pressing the AE-L/AF-L button, by selecting in the custom settings menu .
This button is programmable to give instant access to a personal favourite setting.
In Nikon's defaults, it sets the ISO sensitivity together with the command dial.
However, the custom settings menu
The AE-L/AF-L button is a second programmable button with fewer possible functions, five in total. These are
In the custom settings menu
The default is that the AE-L/AF-L button locks exposure and autofocus, my preference is to control exposure and autofocus independently and set it.
The custom settings menu can swap the directions used for exposure compensation and/or the aperture setting.