The above table is found on P93 in the Users Manual. With this table one can really plan the focussing behavior of the E-M5. The E-M5 Auto Focus action can be activated with either the Shutter Button or a pre-programmed Function Button or the Touch Screen. I like to refer to the first two methods as the traditional way of focussing and using the touch screen as the iPad generation method of auto focussing.
In the above table, the 2 most left columns shows the three different Focussing methods available in the E-M5, Single Auto Focus (S-AF), Continues Auto Focus (C-AF) and Manual Focus (MF) Each of these three focussing methods have 3 to 4 modes the user can select from in the E-M5. In the top row you see the "Shutter Button Function" and the "Button (AE/AF) Function". The table also shows how the shutter button behaves and how the AEL/AFL button behaves in the different user selectable modes.
Lets look at a few examples to see how you can set your E-M5 to operate to your liking. Looking at the above table one can see that the user has the choice between three different methods to focus with the E-M5, Single AF, Continues AF and Manual Focus. The aim is to program the behavior of the shutter button and the AE/AF button. The E-M5 allows the user to really determine how the E-M5 will act at the hallway shutter position or when the shutter is fully pressed. In addition one can decide to completely independently control Auto Focus (AF) or the Auto Exposure (AE) with the E-M5.
Example A:- S-AF (Mode 2 - see the red markings in the above image)
In S-AF, Mode 2 the camera will do a single auto-focus when the shutter is pressed halfway. The E-M5 will not measure exposure when the shutter is pressed halfway. The camera will only measure and lock the exposure when the shutter is fully pressed. One can use the camera in two ways in this mode. First one can turn the camera to a specific subject in the foreground for example, focus on that subject and with the shutter kept in the halfway position one can then move the camera to frame the final image before fully pressing the shutter to capture the image. When pressed all the way the camera will also measure and lock the exposure. Secondly one can use the camera like always, press the shutter halfway to focus on the subject and then all the way to take the image without moving the camera. With any of the two examples one can also use the AE/AF function button (holding down) to lock the exposure.
This is a great method to apply the 2 thirds focus method in landscape images. We know that typically everything within one third focus area in front of the focus point will be in focus and everything in the remaining 2 thirds area behind the focus point will be in focus. The camera aperture determines the range of the in-focus space. If you therefore focus at the horizon you will not benefit from this thirds focus rule. This particular focus mode helps the user to really select a focus point in the scene that will make the best use of this thirds focus rule. The fact that the exposure will be measured completely separately from the focus will give the photographer the opportunity to become even more creative with exposing the image.
Example B:- S-AF (Mode 3 - not market)
In this example the Shutter Button will lock the exposure when pressed halfway or when pressed all the way will activate the shutter. In mode 3 the shutter button will not at all activate any auto focus function. Auto focus will only be activated when pressing the AE/AF function button. Take care that with Mode 3 the function AEL/AF has to be assigned the one of the buttons (Fn-1 or Fn-2). (For Mode's 1 or 2 it is not a must to assign AE/AF function to a button.)
Here are page references in the Users Manual with more information:-
P93 Table with all the functions one can assign to buttons (see image at the bottom of the article)
P48 Auto Exposure metering information including Exposure Lock.
P86 Custom Menu *A - AF/MF set-up page with all set-up descriptions
P43 Different Auto Focus types on the E-M5
P87 Important description of the Rls Priority S and C modes
P46 All about Face Priority
P45 All about the AF Zoom Frame
P44 All about the Focus Target, single, group or all targets
P39 More about the Super Control Panel (SCP)
Example C:- MF with magnifying the AF frame
When using the new 12 - 50 mm Kit lens one has the option to use the Lf-n button on the lens for different selectable functions. For this example I assigned MF (Manual Focus) to the Lf-n button. When doing that my advice is you also activate the "MF Assist" function (P86). To select Manual Focus (MF), press the Lf-n button on the lens and the letters "MF" will be displayed on the camera screen or the view finder. When turning the MF ring on the lens, the screen view will automatically be magnified by a factor of 10. When done the screen will automatically return to the standard view. You will feel that the MF ring on the lens has a unique feel to it, the reason is Olympus use a focus by wire system to do MF. The MF ring is not physically linked to the MF mechanism inside the lens, the manual focussing is therefore done "electronically".
Example D:- C-AF in Mode 2 with and without "Rls Priority C"
Mode 2 separate AF from AE when the shutter is in the halfway position. Personally I prefer this configuration while in C-AF. The camera should only really measure and lock the exposure when the shutter is pressed all the way. Keep in mind that the E-M5 does AE measurement as quick as it does the AF measurements. I have only tried C-AF on subjects that move toward me in a straight line or that moves away from me. I lock the camera onto the subject by pressing the shutter halfway and then keep it pressed halfway until I take the image. You could have a wedding couple walking down the isle. The camera should be on a tripod plus the remote shutter should be fitted to the camera to prevent shake. Set the settings such that the shutter speed is high enough to get a clear image. In the default state the E-M5 will take the image also when the image is not in focus. To prevent that you need to change the "Rls Priority C" setting to "Off" That will prevent the camera from taking the image if the target is not correctly focussed. Under normal conditions this should not be a problem. In my opinion the E-M5 is performing well enough in C-AF to safely set it up for this "wedding" example. The more you practice the better you will know what the limitations are.
Some users report it is better to use the standard 1x1 focus frame when using the C-AF mode. When using C-AF mode, users also report they get good results using Vivid picture mode. With fast moving subjects users said they used the S-AF mode instead. The reason is the FAST AF technology of the E-M5 is quick enough to lock onto and focus on faster moving subjects. The secret is to press the shutter all the way when ready and not to go halfway first.
The E-M5 has many options to tailor the camera exactly to the user needs. One can for example save different camera configurations to the MySet menu's. From this short article it is clear that the camera offers a high level of flexibility programming AF/AE and function buttons. As you will guess, I experiment a lot with different settings while preparing articles. When using the camera I again try to limit the button functions to one only specific "camera" configuration at a time. That helps me to really master the different options I assigned to each of the buttons. One could have a video specific configuration to one MySet space and an image configuration to another, each with its own set of button functions.
In a next article I will have a closer look at the video function of the E-M5.