Nikon Z Focussing Tips

 

I wanted to write this for a long time. Focussing is one of the areas where most beginners seem to fail, the other one being exposure. Both techniques depend on so many circumstances that it is impossible to give a simple advice. But let me try right here at the start. 

There are two techniques which are almost guaranteed to work every time.

• Set the camera to fully automatic mode (AUTO). Cameras have become very advanced by now, and will produce reasonable results in this mode. The focus will not always be where you like, nor will the exposure be the one you had in mind. But it will be okay, and often better than anything you might set if things have to go fast. It is the mode that smartphone photographers use all the time.
• Set the camera to fully manual mode (M). I.e., set the focus to manual focus either by the switch on your lens or a setting in the camera, and set the exposure to M. Now, take your time to fix everything as you like it. Obviously, this is slow. But it is a good way to learn the basics.

Those are at the extreme ends of the speed scale. We want to go somewhere in the middle and get good results as quickly as possible.

Autofocus Basics - Where, When and What

Let us start with the auto focus (AF). For this, the AF system needs to be set for the right focussing area (where), a single or continuous auto focus (when), and optionally for face or subject detection (what). We also need to discuss special features like tracking and dynamic areas. We discuss these concepts independent of a specific camera. 

Where? The smallest focus area is a single focus point. Modern cameras have hundreds covering all of the frame. The point can usually be moved by a joystick or a four-way switch. Of course, you can also touch the display to set the point if it is touch sensitive. Wider focus areas cover several focus points. The camera selects one focus point in this area using its secret algorithm. Often, it is the closest or brightest spot. The focus areas can be moved in the same way as a single focus point. The focus area is usually marked by a rectangle.

When? The focussing can be done once for each shot. Nikon calls this auto focus single (AF-S). By default, the cameras use a half-way press of the shutter to focus. But it is also possible to dedicate a special button instead (AF-ON, see below for back button focus). The focussing can also be done continuously as long as the shutter or AF-ON is pressed to allow for changes in the distance to the subject. Nikon calls this auto focus continuous (AF-C). In any case, there is some sort of feedback for a successful focus.

What? Modern cameras can detect faces and eyes, some even for animals of all kind. Some can detect a moving object in the scene and will follow this object in AF continuous mode. You might have to enable these features in the settings. How well the eye detection works, depends on the camera. Some are able to get every shot right, even in burst mode. Some cameras enable face detection only if the full frame is selected as the focus area, others can search faces in smaller areas.

Tracking. In this mode, the focus area follows a subject. In AF single mode, there is no focussing during the tracking, only at the shot, but in AF continuous the camera will focus while following the subject. Tracking is usually indicated by a rectangle following the subject. Each camera has a different method to start and end the tracking.

Dynamic Areas. In this mode the focus area can be changed a bit if the focus fails in the original area, but succeeds in a neighboring area. The mode makes sens in AF continuous only, where it allows to follow a fast-moving subject. 

The Nikon Z Setup

Let us now discuss, how all this works on the Nikon Z cameras. Other cameras are different, and you need to study your camera to learn the handling.

• To set the focus area and focus mode (where and when), the most comfortable way is to set a button for this setup using the menu f2. I use the button Fn2. The front wheel will then change the focus area and the back wheel the focus mode. 
• The focus modes are single mode (AF-S), continuous mode (AF-C) and manual (M). 
• The selectable focus areas depend on the focus mode. They can be restricted in the menu a8 to speed up the selection.
• To speed up the movement of the focus point by the joystick or four-way knob, you can reduce the number of focus points to half in the menu a5.
• In wide area mode, eye and face detection are enabled by default, (see menu a4). If the camera detects no subject, it will make a reasonable assumption and show you the sharp areas by green rectangles in AF-S, and by red, flashing areas in AF-C.
• Single point focussing is the most precise, but slowest focussing.
• You can set the camera so that it only releases the shutter if a focus has been established. This is the default mode in menu a1 and a2 for continuous and single mode.
• Tracking can be enabled by one of the buttons Fn1 or Fn2 at the front in menu f2. In this case, it can also be disabled with this button. Alternatively, OK enables tracking and - ends it. Pressing OK again releases it from the subject and centers the rectangle.
• Put the tracking rectangle over your subject and focus once in AF-S, or continue focussing in AF-C by AF-ON (i.e., pressing the shutter halfway or holding the AF-ON button). 
• Tracking does not focus in AF-S. It will only focus with AF-ON.
• Or you can start tracking on a subject by tapping on the screen, and end by tapping the EXIT icon. For this, the display mode must be in "focus set". Check the small icon on the left edge of the display for this.
• Dynamic mode is available in AF-C only and indicated by a red rectangle with dots around it. You can place the red rectangle somewhere in the frame where you expect your subject to be. Even if the subject leaves the rectangle briefly, the focus will be hold.
• In AF-C and wide area mode it can be difficult to see the selected focus points. The only flash briefly in red. This mode is most useful for eye and face tracking. Otherwise, a smaller area or the dynamic area is more useful.

Manual Override and Manual Focus

On modern cameras, you can override the AF by turning the auto focus ring on your lens. This allows a more precise, albeit slower, setting of the focus.

If you have enabled the focus peaking in d9 the sharp edges will be highlighted in red. It takes some time to learn to interpret this correctly, Then, it is a great help. The peaking will only appear while the camera is actually focussing. So, either press AF-ON or the shutter halfway down to see the red areas.

Another trick for better sharpness is to zoom in. You can set a button in f2 to zoom in 100% (or 50%, 200%). Focussing will then be done in the zoomed area in single point mode. This is very precise, but slow. The area can be moved by the stick. The display shows the current area in the lower right. I find this most useful with back button focus or in manual focus.

Back Button Focus

When the first cameras with auto focus came on the market, it was considered easiest to focus when the shutter is pressed halfway. The shutter press got a resistance at the point which works more or less good depending on the camera. The idea was to make the photo taking automatic. With the shutter release, the camera should auto focus and automatically set the exposure, all in one press.

This kind of point-and-shoot release has disadvantages as soon as we get more critical to our results. We now use histograms and preview displays to check our exposure before we press the shutter. Likewise, we like to check if the exposure is right beforehand. Pressing and holding the shutter halfway is a cumbersome way to do this.

So, many photographers do no longer focus with the shutter. Instead, they use a dedicated button at the back to set the focus. The best position of this button is below the thumb of the right hand, with the forefinger on the shutter. After a while, pressing this button a millisecond before the shutter becomes natural. 

On the Nikon Z, disable the focussing on the shutter in menu a7. You also need to set a button to AF-ON in f2. By default, this is already set to the button labelled AF-ON.

But you do not have to press it shortly before the shutter. You can now slowly and precisely set and check your focus, concentrate on your composition and scene, and then take the shot. This is especially useful when you focus manually. If you zoomed in to focus, you will like the fact that the shutter no longer changes it, even if you are not in manual focus mode.

Another advantage is that you can mimic AF-S in AF-C mode. In continuous auto focus, you need to hold down the AF-ON button, of course. But you can let it go at any time to stop the focus where it currently is.

Many photographers shy back from this mode, because it takes some time to get used to. Moreover, you need to tell anybody you hand your camera about the change. If that happens often, you can set a user mode. The Nikon Z will save the focus settings for each mode.