Canon T3i Experience

Note that when you enable this, the camera will disable Auto Lighting Optimizer and will limit your ISO range to 200-6400. This will be discussed a little bit more in the Highlight Tone Priority and Auto Lighting Optimizer section.

recommend: 0 - but put in My Menu

C.Fn III: Autofocus/ Drive

C.Fn III-7 - AF-Assist Beam Firing

This setting is to enable or disable the autofocus assist beam, which is a flash of light emitted from the internal or external flash to help the camera focus on the subject. I suggest enabling it, setting 0, unless you are in a situation where it is too distracting in some way. If you never use the internal flash and just a Speedlite, set it on 2: Enable external flash only or 3: IR AF assist beam only which will only use the infrared AF- assist beam and not the series of small flashes of light. Make sure the Speedlite's custom functions have it turned on too.

recommend: 0

C.Fn III-8 - Mirror Lockup

This is the mirror lockup that you might have read about from landscape and macro photographers. By enabling it you reduce that extra little bit of vibration that may cause slight blurring with a long lens or a macro lens. It is only worth using in conjunction with a remote shutter release or the self timer, and a tripod. You definitely don't want to use it all the time, so disable it, and put it in your My Menu if you need it sometimes. This is not the feature to use to raise your mirror for manual sensor cleaning. That feature is under Sensor Cleaning in the Set-up 2 menu. More about Sensor Cleaning later. recommend: 0

C.Fn IV: Operation/ Others

C.Fn IV-9 - Shutter/AE Lock Button

This is used to change the function assigned to the Shutter Button when it is pressed half-way and the AE Lock Button (the one with *). The default setting, 0, is for locking both focus and exposure when you press the Shutter Button halfway (when using Evaluative Metering Mode). You then recompose if necessary and fully press the Shutter Button to take your photo. The problem with this is that if you recompose, the correct exposure may change due to your new framing, and the photo may be slightly or possibly greatly under- or over-exposed because you locked in a different exposure. To prevent this, you can use the AE Lock Button (exposure lock button, [*]) to lock in the exposure of your desired framing. This is the default setting, 0. Exposure lock will be covered later in the Exposure section. The other following settings are for advanced users, and can be returned to later after reading about Back Button Focusing.

Setting 1 separates the exposure lock and the autofocus to 2 different buttons. Pressing the shutter button half-way will lock in exposure but not focus. The [*] button is used to autofocus, and letting go of it will stop AF and lock in focus at that distance. It is

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