At first glance Custom Functions may appear to be tricky to understand. With 25 different Custom Functions available on the EOS 5D Mark II DSLR, and 71 settings within those, it’s little wonder that photographers can take some time to get to grips with them. The camera’s manual tells what they are, but it omits why you might use a particular setting. In this comprehensive guide David Newton examines all of the Custom Function possibilities of the EOS 5D Mark II and reveals what they do and when you might use them.
The Custom Functions on all Canon EOS DSLRs are separated into four groups. Group I deals with Exposure settings; Group II with Image settings; Group III with Autofocus/Drive settings; and Group IV with settings for Operation/Others – in other words how you interact with the camera and how it works.
Custom Function Group I – Exposure settings
C.Fn I -1 – Exposure level increments
This Custom Function allows you to tailor how the exposure adjustments to shutter speed and aperture are made – Option 0 (default) will allow you to change exposure settings in 1/3 stop increments, while option 1 will change it to 1/2 stop increments. If you select 1/2 stop increments, the display in both the viewfinder and on the LCD panel will show two check marks for each increment, telling you that it’s a 1/2 stop change. Unless you have a specific reason to change it, it is best to leave this on the default 1/3 stop setting.
C.Fn I -2 – ISO speed setting increments
This Custom Function, like C.Fn I -1, allows you to choose whether ISO adjustments are made in 1/3 stop or one-stop increments. Unless you specifically want to set one-stop ISO settings – perhaps to speed up changing the ISO at the expense of some options, it’s best to leave this on the default 1/3 stop option.
C.Fn I -3 – ISO expansion
By default the EOS 5D Mark II has an ISO range from 100 to 6400. However, switching C.Fn I -3 to option 1: ‘On’ will allow access to the expansion settings – ISO 50, ISO 12,800 and ISO 25,600, which are named L, H1 and H2 respectively.
These settings should only be used when you really need them, as the image quality will not be as good as at the other ISO settings. However, there is no harm in enabling the setting, so you may as well leave it turned on, unless you don’t want to even be able to accidentally select the higher or lower settings.
C.Fn I -4 – Bracketing auto cancel
If you make use of the exposure bracketing or white balance bracketing functions of the camera the EOS 5D Mark II will determine whether the settings are retained or not. The default setting is ‘On’, which will forget the bracketing settings if the power switch is turned to 'OFF'. Any exposure bracketing will also be cancelled once a flash is ready to fire after turning it on. In this Custom Function option 1, for ‘Off’, will mean that any bracketing settings will be retained, even after turning the camera off and then back on again. If you turn on a flash, the exposure bracketing will be cancelled, but the exposure bracketing settings will be stored in the memory and implemented once the flash is turned off again.
C.Fn I -5 – Bracketing sequence
Like C.Fn I -4, this Custom Function deals with exposure bracketing and white balance bracketing. It determines the order in which bracketed images are taken.
With the default setting 0, it will first shoot the metered exposure, then the underexposed shot, and then the overexposed shot.
With setting 1, it will first take the underexposed shot, then the metered exposure, and then the overexposed shot.
Depending on how you have set the white balance bracketing - i.e. in either Blue/Amber (B/A) direction or Magenta/Green (M/G) direction - this will determine what under or over entails. For adjustments in the B/A direction, under will have a Blue bias, over an Amber bias. With adjustments to the M/G direction under will be Magenta bias, over will be Green bias.
C.Fn I -6 – Safety shift
Safety shift is an automatic setting to allow the camera to change your set exposure values before a shot is taken. If you are photographing a subject where the exposure changes rapidly and erratically, it is possible that you could end up with the wrong exposure. Imagine photographing a footballer running from a shadow area to a highlight area. If the highlight is very bright, and your shutter speed is set to 1/500sec, you may find that the aperture cannot close down enough to achieve the correct exposure.
With Safety shift set to Option 1, the camera will change your shutter speed, in this case making it faster, so you can achieve the correct exposure. This setting will have no effect if you are shooting in Manual or Program mode.
C.Fn I -7 – Flash sync speed in Av mode
By default, Av mode will try to produce a balanced fill flash result. In low light this can mean the shutter speed becomes quite long and you are at risk of camera shake. This Custom Function will stop that. The default setting, or 0, will allow any shutter speed to be set between 1/200sec and 30sec. Setting 1 will choose shutter speeds from 1/200-1/60sec, so you’re unlikely to get camera shake, and setting 2 will lock the shutter speed to 1/200sec.
If light levels are low, then both setting 1 and 2 will most likely result in black backgrounds to your images, although setting 1 may record some ambient light at the slower end of its shutter speed range. If you aren’t worried about the light in the background and achieving a balanced fill flash result, then you should make use of them.
Custom Function Group II – Image settings
C.Fn II -1 – Long exposure noise reduction
This Custom Function lets you choose how noise reduction for long exposures is performed.
- Setting 0 – the default, will not perform long exposure noise reduction.
- Setting 1 – ‘Auto’, will perform noise reduction on exposures over 1sec if noise is detected.
- Setting 2 – ‘On’, will perform noise reduction on all exposures with a shutter speed of 1sec or longer.
A form of dark field subtraction carries out noise reduction, so you may have to wait between shots while the camera captures another exposure of the same length as your set shutter speed. With a shutter speed of 10 minutes, it could take up to another 10 minutes to do the noise reduction. You will be able to continue shooting, as long as the burst indicator in the viewfinder shows ‘1’ or higher.
C.Fn II -2 – High ISO speed noise reduction
This Custom Function determines how much noise reduction is performed on images shot at all ISO settings. Although it is especially useful at high ISO speeds, it will also help to minimise noise in shadows at low ISO speeds as well.
The options are Standard, Low, Strong and Disable. Since noise reduction smoothes digital grain, it may also smooth some fine detail. Therefore it’s best experiment with these settings to find out what works best for you.
If you set Option 2, Strong, note that the maximum burst rate will decrease, as the camera has to carry out more complex calculations so image data is processed more slowly.
C.Fn II -3 – Highlight Tone Priority
Highlight Tone Priority aims to improve the tonal gradation of highlight areas in an image. All cameras have a fixed dynamic range, or a range from shadow to highlight, that they can capture. Highlight Tone Priority shifts some dynamic range from the mid-tones to the highlights to produce smoother tones, with more detail, in the bright areas.
With Highlight Tone Priority set, the ISO range will be limited to 200-6400 and it is indicated by a D+ symbol in the LCD display.
This setting should not be used in low light or when shooting subjects with heavy shadows as it may cause more noise to appear in those areas.
C.Fn II -4 – Auto Lighting Optimizer
Auto Lighting Optimizer will automatically correct an image to make it look better. It works with images where the contrast is low or where the subject has come out too dark, or when using flash. It will even out the image to improve the look. There are four settings – Standard, Low, Strong and Disable. Like the noise reduction settings, you should experiment with these settings to see what works best for you.
If you shoot in RAW and use Canon’s Digital Photo Professional software (free in the box with EOS DSLRs), you can add or remove Auto Lighting Optimizer settings in the RAW processing.
Custom Function Group III – Autofocus/Drive settings
C.Fn III -1 – Lens drive when AF impossible
In some situations, the camera may simply not be able to focus. These are usually situations where there is low contrast and no detail for the camera to lock onto. A good example is photographing a bird against a blue sky – if the AF point drifts off the bird to the sky, the camera may not be able to focus.
This Custom Function allows you to choose whether the camera attempts to focus or not. If focus search is set to 'On', setting 1, the lens may hunt through the range. With it set to 'Off', setting 2, the lens will not try to acquire focus until there is something to focus on. This is useful as if the lens hunts for focus it’s possible you won’t be able to see the bird at all, even when pointing directly at it, as it could be completely out of focus. In situations like this, you should set setting 1.
If you use this setting though, remember that in low light, the camera may simply decide there is nothing to focus on and it will not try. Unless you are aware you have this set, it can be quite frustrating.
This setting is most commonly used when shooting with long telephoto and super telephoto lenses.
C.Fn III -2 – Lens AF stop button function
Some Canon EF lenses feature an AF stop button mounted on the lens body. This Custom Function allows you to choose what the function of that button is.
- Setting 0 – this means it will act as an AF stop button, so you press it during AF to momentarily halt the AF function, for example, when an obstacle crosses in front of your subject.
- Setting 1 – makes it an AF start button, so you can activate AF from this button rather than the shutter button.
- Setting 2 – makes the button perform an AE lock, so you can lock your exposure and then recompose and shoot
- Setting 3 – the function will depend on whether you are using manual or automatic AF point selection. If you are using Manual AF point selection, pressing the button will switch from the manually selected AF point to automatic AF point selection, but only while you keep the button pressed. If you are using automatic AF point selection, pressing the button will switch to the central AF point, but, again, only while you hold it down.
- Setting 4 – will switch between One Shot focus and AI Servo focus so you can switch from shooting a static subject, to a moving one.
- Setting 5 – this will activate the lens IS mechanism. With setting 5 chosen, half pressing the shutter button will not activate the IS.
C.Fn III -3 – AF point selection method
This Custom Function allows you to choose how you select your AF points. The default setting, 0, requires you to press the AF point selection button then use the Main and Quick Control Dial to navigate around the AF points.
- Setting 1 – Multi-controller direct, this will speed up the process. Instead of pressing the AF point selection button, you simply use the multi-controller on the back of the camera like a joystick to move around. Pressing straight in will choose the centre point. If you want to use Auto point selection, simply press the AF point selection button.
- Setting 2 – Quick Control Dial direct, this allows you to just use the Quick Control Dial directly without having to press the AF point selection button first. Usually the Quick Control Dial is used for exposure compensation. If you still want to use exposure compensation, you need to press the AF point selection button and then use the quick command dial.
C.Fn III -4 – Superimposed display
Sometimes, the AF point flashing in the viewfinder when focus is achieved can distract you from the view of the subject. This Custom Function allows you to turn it off. By default, it is set to option 0: ‘On’, however, option 1: ‘Off’ will stop it flashing. The AF points will, however, still light when you are selecting them.
C.Fn III -5 – AF assist beam firing
If you are using an external Speedlite flashgun, you can choose whether to have the AF assist beam firing, to help with focusing in low light, or not. By default it will emit a grid, but if you are working with other photographers photographing the same subject, it is possible that another photographer may take a picture and see your AF grid if you happen to be focusing at the same time.
This setting can be over-ridden by the Custom Function on the Speedlite flashgun. If the Speedlite is set to not fire, then this Custom Function in the camera will have no effect – the beam won’t fire, even if this Custom Function is set to have it firing.
C.Fn III -6 – Mirror lockup
When shooting at fairly slow shutter speeds and using a tripod, it can be advisable to use mirror lockup. This will then require two presses on the shutter release – one to raise the mirror and the second to take an image. By raising the mirror well before the exposure, any vibration caused by the mirror motion will not affect the image.
This Custom Function is best used with shutter speeds from around 1/60sec to around 1sec and should only really be used if you are using a remote release and a tripod. If you don’t have a remote shutter release, then touching the camera will negate any advantage of mirror lockup.
C.Fn III -7 – AF expansion with selected point
The EOS 5D Mark II has six AF assist points located around the central AF point that help when you use the central point and AI Servo focusing. It is useful for subjects that move erratically – it will give you a larger AF area to focus with and remove the need to keep the centre point directly on the subject.
C.Fn III -8 – AF Microadjustment
When looking at your images, you may notice that they are not exactly in focus where you want to be. You can only tell this after looking at lots of images. You will build up a feel for whether your lens and camera focus slightly in front of where you think they should, or slightly behind.
AF Microadjustment allows you to adjust the calibration between the camera and lens to bring the plane of focus to the point you expect it to be.
The settings are ‘Disable’, ‘Adjust all by same amount’ or ‘Adjust by lens’. The camera can store adjustments for up to 20 lenses at a time. This lens data is stored by lens model, not serial number, so if you have two lenses of the same model, the camera will treat them the same.
You can adjust the plane of focus by up to +/-20 steps forwards or backwards. If you find the camera requires a lot of adjustment, it’s best to send it into a Canon Service Centre to have the camera and lenses adjusted by computer calibration.
If you clear all the Custom Function settings, the camera will still retain any calibration you have done but the setting will be 0 – disable.
This setting isn’t something you should use by default. It is more for use when you are shooting in the field, knock, or drop, your lens and can’t get the camera and lens to a Canon Service Centre to be recalibrated. If you think your lenses are a long way out of alignment, you should send them to a Canon Service Centre to have them properly calibrated.
Custom Function Group IV – Operation/Others settings
C.Fn IV -1 – Shutter button/AF-ON button
This is one of the most used Custom Functions as it allows you to set back button focus, so you can shoot static and moving subjects without having to change the AF mode.
For shooting moving subjects, either option 2 or 3 are the most likely. Your choice will depend on whether you use AE lock, and want immediate access to it on the shutter button, or not. An example of its use would be when photographing a moving subject that then stops, such as a bird flying to a perch. Normally you would have to switch from AI Servo to One Shot if you wanted to recompose, but with C.Fn IV -1-2 set, you can track the subject in AI servo by pressing the AF-ON button. As soon as it stops, you can focus on the eye with your selected AF point, then release the AF-ON button, recompose and shoot. Because the shutter button doesn’t activate autofocus, the focus will not change when you recompose despite being in AI Servo.
C.Fn IV -2 – AF-ON/AE lock button switch
Enabling this Custom Function switches all the functions of the AF-ON button and AE lock button. This is used in combination with C.Fn IV -1 to perform focusing with the AE lock button rather than the AF-ON button.
With this set, in playback mode, the AE lock button will not zoom out of a review image. To zoom out you will need to use the AF-ON button.
C.Fn IV -3 – Assign SET button
In the default configuration, the SET button has no function. However, you can assign functions to the SET button to make them quicker or easier to access. There is the choice of seven settings that can be applied. If you apply one of the settings, pressing the SET button will bring up the setting screen on the rear LCD panel. The settings are:
- 0: Normal (disabled)
- 1: Image quality
- 2: Picture Style
- 3: Menu display
- 4: Image replay
- 5: Quick Control screen
- 6: Record movie (Live View)
If you have already set up Live View Mode/Movie shooting to be accessed from the SET button, that setting will over-ride any setting made in this Custom Function. However, if you haven’t and you want a quick way to access Movie shooting without having to enter the Live View Mode, choose option 6. This will enter EOS Movie Mode and start movie recording directly.
C.Fn IV -4 – Dial direction during Tv/Av
Some photographers prefer the dials on the camera to work in the opposite direction, so rotating the Main dial right in Av makes the aperture larger rather than smaller. To do this, you can reverse the dial direction using C.Fn IV -4-1.
If you activate this function, then in Manual mode, both the Main and Quick Control Dials will be reversed. In Tv and Av, only the Main dial will be reversed while the Quick Control Dial will function the same.
C.Fn IV -5 – Focusing screen
This Custom Function should be set to match the focusing screen you are using. The EOS 5D Mark II has interchangeable focusing screens that can be used depending on your needs. Simply select the setting to suit your screen. If you’ve never changed your focusing screen, you can simply leave it on the default setting.
- 0: Eg-A – standard focusing screen
- 1: Eg-D – for the matte with grid screen
- 2: Eg-S – For the super precision matte screen