AF-C

The camera also has a “Continuous AF” mode setting (denoted by “AF-C”), which can be used when you’re shooting sports (or anything that moves). When this mode is enabled you are essentially telling the camera “my subject is moving. Even when you’ve found focus, keep trying to focus on the subject because my subject will not stay still!” Keep in mind that in Continuous mode, once the camera achieves autofocus, it will not give you a steady green light and an audible “chirp”. Instead, it will continue to track and refocus (the subject is moving after all, right?) in an attempt to keep the subject in focus until the final shot is taken. You can always tell when you’re in Continuous focus mode, because the green focus indicator along the bottom left corner of the screen is surrounded by two sets of parentheses, which is supposed to convey movement.

AF-A

Tired of constantly switching between AF-S and AF-C modes? AF-A will choose for you intelligently. That's the idea, anyway; however there have been many occasions where I was not happy with its decisions and it kind of got in my way. Not recommended.

DMF

“Direct Manual Focus” mode means it will start out in AF-S mode (focus on a subject, then stop trying to focus) and then it will go directly into manual focus mode, where you can quickly tweak the focusing if you so choose. It will stay in manual focus mode for as long as you hold the shutter release button down halfway. This tends to be most useful when shooting macro photos of flowers that move slightly in a gentle breeze.

That's the official purpose, anyway. As mentioned previously at the end of “Other Essential Customizations” (Section 2.3), DMF is even more useful when you have Peaking Level and Peaking Color enabled (Section 7.10). With Peaking Level enabled, as soon as the camera switches to Manual Focus mode, the things that are in focus (areas of highest contrast) will appear in a certain color, allowing you to see instantly whether the camera focused accurately or not. Think of it as the Mother of All Focus Confirmation indicators.

This was even more important for earlier E-mount cameras, which were all contrast-detect in AF-S mode and therefore was vulnerable to false positives. So it's not needed as much anymore; however this kind of focus confirmation is comforting to me.

MF

Manual Focusing, which probably needs no explanation. The camera will actually magnify the center of the viewfinder for easy focusing if MENU --> 1 --> MF Assist is set to ON (Section 7.38). Peaking Level functions (as described above) work here also, but for some reason are harder to see.

I should mention here that if you’re after absolutely critical focus, manually focusing using the MF Assist feature will get you accuracy greater than if you just relied on autofocus. This is especially true in macro and other shots that require the sharpest detail.

 

TIP: You can fine-tune the AF-S and AF-C settings by telling the camera either "Don't take the picture unless you think it's in focus", or "Do your best to AF but take the picture when I say so, no matter what!". The Priority Setting function is described in Section 7.22.

TIP: As a shortcut, when you put the camera into Sports Action mode (Section 6.38.2), the camera automatically invokes AF-C, continuous shooting "high" and wide area focus for you.