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Niet beschikbaar in
March 2010

Canon’s DSLR Custom Functions can appear to be a minefield. With 62 available on the Canon EOS-1D Mark IV it can seem like a huge challenge to understand them all, but ignoring them means you are potentially missing out on a superb avenue of flexibility for your DSLR. The camera’s manual will tell you what the Custom Functions do but crucially they miss out on an explanation of why you might use a particular setting. David Newton takes an in-depth look at all of the EOS-1D Mark IV’s Custom Functions and reveals what they all do...

The Custom Functions on the EOS-1D Mark IV are separated into four different groups. Group I deals with exposure settings; Group II with Image settings, flash exposure and display settings; Group III with settings for Autofocus and drive settings; and Group IV with settings for 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 1/3rd of a stop increments, Option 1 will make it full stop increments. Option 2 will change it to half-stop increments. If you select half-stop increments, the display in both the viewfinder and on the LCD panel will show two check marks for each increment, telling you it is a half-stop change. Unless you have a specific reason to change it, it is best to leave this on the default 1/3rd stop setting.


The main Custom Function menu of the EOS-1D Mark IV as seen in the camera’s main LCD screen.

C.Fn I -2 – ISO speed setting increments

This Custom Function allows you to choose whether ISO adjustments are made in 1/3rd 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 1/3rd stop option.

C.Fn I -3 – Set ISO speed range

By default the EOS-1D Mark IV has an ISO range from 100 to 12,800. However, for shooting in very low light conditions, or when you want to achieve a longer shutter speed, you will need to enable the expansion settings. On the EOS-1D Mark IV you have the ability to set certain ranges of ISO speeds as well – this can be used if you want to limit the maximum or minimum ISO speed that can be used – to speed up selection or to avoid shooting at certain ISO speeds. To set this, you choose ‘register’ and select the highest and lowest options. The highest ISO speed range is from 100 to strong (102,400) while the lowest range is from L (50) to H2 (51,200); H1 is ISO 25,600. With the highest and lowest options set, choose apply and then select 'Enable'.

C.Fn I -4 – Bracketing auto cancel

If you make use of the exposure bracketing function of the camera to take three, five or seven pictures at a time with different exposures, this Custom Function will determine whether the exposure bracketing and white balance bracketing settings will be cancelled after the image set – option 0: (On) – or left on – option 1: (Off). If you plan to bracket exposure several times in quick succession, then you should set Option 1 so that you only need set the bracketing amount once rather than resetting it after each sequence. If you select Option 1, the camera will retain the autoexposure bracketing and white balance bracketing settings even after the camera is turned off. Turning a flash on will cancel any autoexposure bracketing settings, but they will be retained in the memory and re-instated once the flash is turned off.

C.Fn I -5 – Bracketing sequence

Like Custom Function I - 4 this deals with exposure bracketing. It determines the order in which you want the bracketed images to be taken. With the default setting 0, it will take the metered exposure, the underexposed image, then the overexposed shot. With setting 1, it will take under exposed, then metered exposure, then overexposed. Setting 2 takes overexposed, the metered exposure then underexposed.

© David Newton: Custom Function III –19

Custom Function III -19 allows you to limit or set the continuous shot count from between 2 and 99 shots in a row. (Click here to see an example of bracketing sequence.)

C.Fn I -6 – Number of bracketed shots

Unlike other EOS models, the EOS-1 series cameras allow you to shoot bracketed exposures in sequences of two, three, five or seven-shot sequences. This is useful if you want to shoot High Dynamic Range (HDR) images to add together later as you can shoot seven images in a sequence with different exposures to obtain a good HDR image set.

Setting 0 (default) will create a three shot bracket. Setting 1 takes two images, setting 2 takes five images, and setting 3 takes seven images. This Custom Function will work in conjunction with C.Fn I -5, so if you do want to create HDR images, use C.Fn I -6-3 and C.Fn I -5-1 to ensure they are in order. If you use C.Fn I -5-0, the sequence will start with the metered exposure, then go down and back up on the exposure scale.

C.Fn I -7 – Spot metering link to AF point

The EOS-1 series models allow you to use spot metering but to have it linked to a focusing point, rather than being limited to the centre of the frame. This allows you to set your metering from the subject you are focusing on, rather than having to meter from the centre and use excessive compensation.

This C.Fn provides two options: 0 – Disable, which will use the centre of the frame, and 1 – Enable, which will use the active AF point. C.Fn 1, Enable, is only available when C.Fn III -10 is set to option 1, 2, 3 or 4 for number of selectable AF points. If you are using all 45 AF points in Manual selection, or with automatic AF point selection, the spot metering will revert to the central area, even if C.Fn I -7-1 is set.

C.Fn I -8 – 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.


Custom Function II -3 offers the capability of enabling or disabling Highlight Tone Priority.

With Safety shift set to Option 1: Enable (Tv/Av), 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. With Safety shift set to Option 2: Enable (ISO speed), the camera - in Program AE, shutter-priority AE (Tv), and aperture-priority AE (Av) modes - will change the ISO speed automatically to obtain a correct exposure when the subject’s brightness changes erratically and the correct autoexposure cannot be obtained. With settings 1 and 2 safety shift also works with flash.

C.Fn I -9 – Select usable shooting modes

To speed up working with the camera, you can disable any of the shooting modes you don’t use. If, for example, you only use Av and M, you can disable P, Tv and Bulb, so that you can switch between Av and M quicker and without taking your eye from the viewfinder. To set, simply select the modes you want accessible by check marking them and then choosing 'Enable'.

C.Fn I -10 – Select usable metering modes

Like C.Fn I -9, this Custom Function allows you to disable metering modes you don’t use for quicker access to the ones you do. Perhaps you never use centre-weighted or partial metering, preferring instead to use Spot and Evaluative. You can disable the two you don’t want and then switch between the two you do quickly and easily. Set the modes you want available by registering them and then choosing 'Enable'.

C.Fn I -11 – Exposure mode in manual exposure

Some photographers have a specific way of metering when shooting in Manual exposure mode. This Custom Function allows you to default the camera to switch to any of the four metering modes as soon as the camera is set to Manual exposure. There are 5 options: 0 (default) – Specified metering mode; 1: Evaluative metering; 2: Partial metering; 3: Spot metering; and 4: Centre-weighted metering. If you set any of the options 1-4, you will not be able to change the metering mode during shooting as it will be locked to the specified setting.

C.Fn I -12 – Set shutter speed range

In some situations, you may wish to limit the shutter speed range available to the camera – perhaps to ensure it doesn’t drop below a pre-determined speed to avoid camera shake or subject movement. You can register the highest shutter speed between 1/8000sec and 15sec, and the lowest shutter speed from 30sec to 1/4000sec. Once registered, choose ‘Enable’ to activate the range limit.

C.Fn I -13 – Set aperture value range

Like limiting the shutter speed, you may on occasion wish to limit the aperture range to provide a required depth-of-field or to achieve a certain look to your images. This custom function will allow you to set the smallest aperture in the range of f/91 to f/1.4 and the largest aperture from f/1.0 to f/64. After entering the settings select 'Apply'.

C.Fn I -14 – Apply shooting/metering mode

Sometimes you need to switch to a ‘default’ setting quickly without taking your eye away from the viewfinder. This Custom Function allows you to hold down the AE lock, or Star, button and change to previously registered settings. You can register either shooting mode, metering mode, shutter speed, aperture or exposure compensation and recall them immediately.

To register the setting, choose the option you would like to be available and then select enable. This setting cannot be used if you set the shooting mode to Bulb, though in this situation you are unlikely to need to rapidly recall a particular setting.

C.Fn I -15 – 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 1/300sec and 30sec. Setting 1 will choose shutter speeds from 1/300-1/60sec, so you’re unlikely to get camera shake, and setting 2 will lock the shutter speed to 1/300sec.

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 are not worried about the light in the background and achieving a balanced fill flash result, then you should make use of them.


Custom Function IV -11 on the EOS-1D Mark IV allows for quick starting of the camera’s EOS Movie shooting setting.

C.Fn I -16 – AE Microadjustment

This setting is only to be used if you want to match several cameras' exposure response or to tailor the exposure response for personal preference. It will allow you to fine tune the exposure level up to +/-1stop in 1/8th of a stop increments. Option 0 is Disable and Option 1 is Enable.

If you want to force the images to be brighter, set a positive value. To make images darker, set a negative value. Once setting 1 is enabled, pressing the INFO. button will display the adjustment screen.

C.Fn I -17 – FE Microadjustment

Like AE Microadjustment, this setting is only to be used in certain rare cases. It will allow you to tailor the exposure of the flash to suit your requirements. Like AE Microadjustment, flash exposure bias can be set up to +/-1 stop in 1/8th stop increments. Option 0 is Disable and Option 1 is Enable. With this Custom Function enabled, pressing the INFO. button will display the adjustment screen.

Custom Function Group II – Image/Flash exposure/Display 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.

Noise reduction is carried out by a form of dark field subtraction, 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 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. You should therefore experiment with these settings to find out what works best for you.

If you set Option 2, Strong, 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 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 200-12,800 and it is indicated by a D+ symbol in the LCD display. This setting shouldn’t 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 the Canon Digital Photo Professional software, you can add or remove Auto Lighting Optimizer settings in the RAW processing.

© David Newton

Custom Function III -4 allows you to adjust AI Servo AF tracking methods to follow particular moving subjects.

C.Fn II -5 – E-TTL II flash metering

There are two flash metering algorithms you can use for flash metering – the metering pattern you choose for ambient light metering does not affect the flash exposure. The flash metering algorithm determines how the camera reads the light reflected from the pre-flash – either as an evaluative metering algorithm (Setting 0), or as an average metering algorithm (Setting 1) where the light is read from all the metering zones and averaged without trying to determine where the subject is. You should try both in a controlled environment to see what works best for you.

C.Fn II -6 – Shutter curtain sync

This Custom Function allows you to choose whether the flash will sync with the first or second shutter curtain. The options are 0 – First curtain sync, or 1 – Second curtain sync.

While flash can be used for static shots, it can also be used for more creative images and to show motion. With a flash on-camera, you can use second curtain sync flash to make the flash fire just before the second shutter curtain closes rather than as soon as the first shutter curtain opens. This is useful when you’re shooting in low light with longer shutter speeds and can be used to freeze the subject at the end of the exposure while still allowing for the motion to be captured in ambient light behind the subject and look natural.

If you choose second curtain sync, be sure to set the shutter speed to 1/50sec or slower. If you use a shutter speed of 1/60sec or faster first curtain sync will be used.

C.Fn II -7 – Flash firing

This setting will enable or disable the firing of a hotshoe connected flash or one that’s connected to the PC sync socket of the camera. It is most commonly used when you don’t want the flash to fire, but you do want to make use of the focusing lamp built into the EX Speedlites. The options are 0 – Enable, so the flash fires and 1 – Disable, so the flash will not fire.

C.Fn II -8 – Viewfinder info. during exposure

By default, during the exposure, the shooting information such as shutter speed, aperture, remaining shots etc. will not be shown in the viewfinder. However, if you want it to be displayed, simply set this Custom Function to setting 1. In Bulb mode, info will still not be displayed in the viewfinder during the exposure, so this Custom Function is really for when shooting bursts of images.

C.Fn II -9 – LCD panel illumination during Bulb

If you shoot in Bulb mode regularly, you may find it useful to set this Custom Function to option 1 – On during Bulb. This will keep the LCD panel illuminated once you start a Bulb exposure, making it easy to check the elapsed exposure time. Be aware though that it may shorten the battery life as more power is consumed to keep the screen alight.

C.Fn II -10 – INFO. button when shooting

The INFO. button on the back of the camera can provide a wealth of information however, you may find some information more useful than others. By default (setting 0), the camera will display the shooting functions so it mimics the display of the top LCD panel. From this display, you can also use the buttons for Mode, AF/Drive, Metering/FEC, Bracketing, ISO, Exposure compensation and AF point selection and then make your settings from the rear screen where settings are easiest to see.

Choosing Option 1 will mean the rear LCD display shows camera settings instead of shooting settings. This includes settings such as Picture Style settings, Colour space, WB shift and bracketing info, Microadjustment settings, remaining shots on each memory card, image rotation and date and time.

Custom Function Group III - Autofocus/Drive settings

C.Fn III -1 – USM lens electronic MF

Some lenses feature an electronic focus motor that needs to be powered from the camera. There are three settings to this custom function. 0: Enable after One-Shot AF, 1: Disable after One-Shot AF, 2: Disable in AF mode.

© David Newton

Custom Function III -16 is Orientation linked AF point and allows for using the same AF point or a different AF point for vertical and horizontal shooting.

The lenses which feature electronic focus motors are:

  • EF28-80mm f/2.8-4L USM
  • EF50mm f/1.0 USM
  • EF85mm f/1.2L USM
  • EF85mm f/1.2L II USM
  • EF200mm f/1.8L USM
  • EF300mm f/2.8L USM
  • EF400mm f/2.8L USM
  • EF400mm f/2.8L II USM
  • EF500mm f/4.5L USM
  • EF600mm f/4L USM
  • EF1200mm f/5.6L USM

With these lenses, and the default setting, after focus is achieved with the focus mode in One-Shot, you can adjust the focus manually. If you want to use full-time manual focusing with one of these lenses, you need to C.Fn IV -1-2 or C.Fn IV -1-3 to enable the AF-ON button to operate the AF.

This Custom Function exists to stop you from accidentally knocking the focus ring on the lens and changing focus. The focus rings on these lenses are very sensitive to enable precise focusing.

© David Newton

Custom Function III -16 is Orientation linked AF point and allows for using the same AF point or a different AF point for vertical and horizontal shooting.

C.Fn III -2 – AI Servo tracking sensitivity

This Custom Function has five levels, from slow to fast:

  • 0 = Standard sensitivity – AF will momentarily pause if the AF point sees another subject while tracking.
  • -2 = Slow – Tracking will pause for a longer period when AF is disrupted to allow you to find the original subject with the AF point.
  • -1 = Moderately slow – Pause length will be between -2 and 0.
  • +1 = Moderately fast – The AF system will respond faster to a change in subject position.
  • +2 = Fast – AF system will not pause. If the subject escapes the AF point, the camera will instantly re-focus on the area the AF point is currently covering.

The focus tracking sensitivity refers to how the camera responds and switches to another subject during focus tracking. This response sensitivity refers to how long the camera waits before switching to a new target subject when the current target subject escapes an AF point. It does not adjust how quickly to autofocus tracks. The shorter the response time, the faster it will switch subjects to track a new subject. Therefore, if you want to quickly track changing subjects, set the sensitivity to a faster level.

However, if you want to track the same subject as much as possible without switching to another subject, set this sensitivity to a slower level to force the camera to continue tracking the same subject even if a distracting subject enters the frame or if the subject is erratic and likely to escape from an AF point.

You should try each of the settings out to find the one that works best for you, but generally, you will find setting -1 or -2 for fast moving, erratic subjects produces better results.

C.Fn III -3 – AI Servo first/second image priority

For AI Servo shooting, you can adjust the priority for the first shot or the second shot, and subsequent shots. It deals with two issues: how quickly the camera will fire if you suddenly press the shutter button fully, and if the shutter button is held down for continuous shooting, whether AI Servo AF will always take time to ensure correct focus for each shot (which may result in slowing down the drive speed), or whether the camera will always fire at top fps speed (even if proper focus cannot be ensured for each shot in the sequence).


The Custom Function screen for High ISO speed noise reduction, C.Fn II -2, with setting options showing.

There are four settings:

  • 0: AF priority/Tracking priority – this will give more time to achieve focus before releasing the shutter and then during continuous shooting, focus tracking will be given time to keep accurate focus.
  • 1: AF Priority/Drive speed priority – like setting 0, the first shot will prioritise focusing. However, after that the camera will try to maintain the maximum shooting speed. This is useful if the subject is large and easy to focus on, or not moving over great distances.
  • 2: Release/Drive speed priority – this will fire the shutter as quickly as possible for the first shot, not giving as much time to finding focus. For subsequent shots, the camera will continue to fire at the maximum frame rate in preference to giving time to focus driving. If you have to capture the moment at all costs, this is a good option to use.
  • 3: Release/Tracking priority – this will work like option 2, in that priority is given to releasing the shutter, but for second and subsequent images, the camera will then pass priority to focus tracking rather than trying to maintain the maximum frame rate.
C.Fn III -4 – AI Servo AF tracking method

With more than one AF point active, using either Automatic point selection or manual point selection with AF point expansion (C.Fn III -8-1/2/3) this Custom Function instructs the camera how to handle a second subject that may enter the focusing point area. In some situations you may want the camera to obtain focus on whatever the closest subject is you are tracking (C.Fn III -4-0). At other times, you may want the tracking to stay with the initial subject you focused on regardless of what else enters the focusing area even if it is closer than the initial subject (C.Fn III -4-1). This Custom Function will be totally disregarded if only one AF point has been selected.

There are two settings:

  • 0: Main focus point priority – With this setting, the camera will focus on any subject that appears under the main focus point, even if it is closer than the subject that you were tracking.
  • 1: Continuous AF track priority – As long as one of the expanded AF points can still detect the subject, the camera will continue to focus on it, even if there is a different subject covering the main, selected focus point.

Continuous AF track priority is effective for sports such as football or slalom skiing or anything where subjects are likely to enter the AF area in front of the subject being tracked. Football players often cross in front of each other, which can distract the AF system. If you are tracking a player with automatic AF point selection and another player cuts in front of your main subject to tackle him, the player in front could distract the autofocus. With automatic AF point selection, the camera will select a different autofocus point in order to maintain focus on the first target subject. If the player appearing in front of the first target is at almost the same distance as the first subject, the camera may not be able to distinguish the distance difference and might lose the target subject.

C.Fn III -5 – 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 on to. 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.


There are four settings for Auto Lighting Optimizer in Custom Function C.Fn II -4.

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 with long telephoto and super telephoto lenses.

C.Fn III -6 – 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 - means it will act as an AF stop button, so you press it during AF to momentarily halt the AF function – when an obstacle crosses in front of your subject for example.
  • Setting 1 - will make it an AF start button, so you can activate AF from this button rather than the shutter button.
  • Setting 2 - will make the button perform an AE lock, so you can lock your exposure and then recompose and shoot
  • Setting 3 - 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 - will activate the lens IS mechanism. With setting 5 chosen, half pressing the shutter button will not activate the IS.
  • Setting 6 - allows you to switch to a registered AF point. To use this, you need to register an AF point and then holding down the AF stop button and pressing the FEL button on the camera will make the switch to the AF point.
  • Setting 7 - gives access to spot AF focusing. This is not available with lenses that don’t have AF Stop buttons. Spot AF uses a narrower active area of the AF sensor so you can focus on a smaller, more precise area of the subject. This is especially useful when shooting small subjects a long way away, or when shooting “through” obstacles – for example, branches in trees to a bird behind.
C.Fn III -7 – AF Microadjustment

When looking at your images, you may notice that they are not exactly in focus where you want them 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. This AF Microadjustment Custom Function 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 is 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 is really not something you should use by default. It is more for use when you are in the field, knock or drop your lens and cannot 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.

C.Fn III -8 – AF expansion with selected point

With 45 AF points to select from, even if you only have one AF point manually selected, the camera can make use of the others to expand the area over which focus is achieved. This is useful when tracking fast moving subjects as it provides a larger area and makes tracking easier.


Via Custom Function I -3 the EOS-1D Mark IV’s ISO speed range can be expanded up to ISO 102,400.

There are four settings:

  • 0: Disable – only the selected AF point will be used.
  • 1: Left/Right AF point – the points located immediately either side of the selected AF point will be used.
  • 2: Surrounding AF points – all points surrounding the selected AF point will be used.
  • 3: All 45 points area – if you have a single AF point selected, the row of six AF points above and below, and three AF points either side will also be active in tracking the subject. If the subject moves to another AF point within those expanded 18 points, the expansion area will also shift and will centre on the currently active AF point. As long as the subject remains within the AF area frame, it will be focused as the expansion area can make use of all 45 points.

If you are using One Shot AF with option 3, AF will still be performed, using any of the expansion points, even if focus cannot be achieved with the selected AF point.

C.Fn III -9 – Multi-controller while metering

With 45 cross-type AF points, being able to select them quickly is important if you’re to capture the moment. Custom Function III -9 allows you to make use of the multi-controller to do this. Instead of having to press the AF point selection button and then use the front and rear command dial, the multi-controller can be moved to directly select any of the AF points. If you want to make use of the extra AF points (39 of which are cross-type sensitive) for freedom in composition especially when tracking moving subjects, then being able to get to any one of them with the use of only one button will make it quicker and easier to do.

© David Newton

Custom Function IV -1 offers control over the shutter button/AF-ON button - it allows you to set back button focus so you can shoot static and moving subjects without having to change the AF mode.

C.Fn III -10 – Selectable AF point

Some users find the ability to select from 45 points either confusing or too slow in fast moving situations. C.Fn III -10 allows you to limit the number of AF points you can manually select from.

There are five possible settings:

  • 0 (default): All 45 points
  • 1: 19 points – this provides the same 19-point arrangement as found in the EOS-1D Mark III.
  • 2: 11 points – sets 11 manually selectable AF points.
  • 3: Inner 9 points – 9 points are manually selectable, located around the centre of the AF area.
  • 4: Outer 9 points - 9 points are manually selectable, located around the outer ring of the AF area.
C.Fn III -11 – Switch to registered AF point

If there is a particular AF point that you like using, you can register it and switch to it immediately using either the multi-controller, or the AE Lock button.

To register an AF point, select the point and then hold down the AF point selection button and ISO button. The LCD panel will display (---) HP for automatic selection, SEL ( ) for centre AF point, and SEL HP for an off-centre AF point.

To switch to the registered AF point use either the Multi-controller, C.Fn III -11-1, or the AE Lock button, C.Fn III -11-2.

If you change the settings on C.Fn III -10 for the selectable AF points, the registered AF point will be cancelled and it will default to the central AF point.

C.Fn III -12 – AF point auto selection

This Custom Function dictates whether you can easily enter the automatic AF selection mode or not. It is only effective when combined with direct Quick Control Dial access to AF points (C.Fn IV -3-1). It also affects whether you can engage the automatic AF point selection mode with the Main Control Dial, after pressing the AF point selection button. If you rarely or never use automatic AF point selection, then C.Fn III -11-1 is probably the most suitable setting. If you often use automatic AF point selection, then C.Fn III -11-2 may prove more useful.

It has three settings:

  • 0: Quick Control Dial direct:disable/Main Dial:enable
  • 1: Quick Control Dial direct:disable/Main Dial:disable
  • 2: Quick Control Dial direct:enable/Main Dial:enable

The setting before the / applies to the Quick Control Dial function with C.Fn IV -3-1 set. The setting after the / applies to the Main Dial function when the AF point selection button is pressed.

C.Fn III -13 – AF point display during focus

Some people prefer not to have the AF point in use continually displayed in the viewfinder, preferring a clean, uncluttered look that allows them to see the scene clearly and easily. C.Fn III -13 allows you to tailor this to suit your preferences. Option 0, the default setting will display the AF point whenever focusing is active. Option 1 ‘Off’, will not display the AF point at all. Option 2 ‘On’ (when focus achieved) will only light the AF point once focus is achieved at that focus point.

C.Fn III -14 – AF point brightness

When shooting in bright conditions it can be difficult to see the AF point displayed in the viewfinder. To help with this, you can select Option 1: Brighter, to make the AF points in the viewfinder easier to see.

C.Fn III -15 – AF assist beam firing

If you are using an external Speedlite flashgun, you can choose whether to have the AF assist beam fire 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 – if the Speedlite is set to not fire, then this Custom Function in the camera will have no effect – the beam will not fire even if this Custom Function is set to have it firing.

C.Fn III -16 – Orientation linked AF point

This Custom Function is designed to make it faster for you to switch AF points when you change from shooting horizontally to vertically. If you’re shooting portraits you’ll find this especially useful as it will save you from manually having to change the AF point when you switch from horizontal to vertical orientation. The camera can be configured with three different AF points that are selected automatically when you turn the camera. You can have a point for horizontal and a point for each vertical – grip up and grip down. The only thing to be aware of is if you shoot ‘creative’ angles – the camera can detect this as a rotation and it may jump to a different AF point.

This Custom Function can prove useful to sports photographers especially, for example when photographing a 100m race – you can start with the camera horizontally to get the whole field in, then as you turn to a portrait shot for the winner crossing the line, the AF point can already be selected by the camera.

The options are 0: Same for both vertical/horizontal – so the AF point will not change when you rotate the camera (this is the default setting). 1: Select different AF point. If you set option 1 and register AF points, then be aware that clearing camera settings will also clear the saved AF points and the centre point will be used for all.

C.Fn III -17 – 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 – if you don’t have a remote shutter release, then touching the camera will negate any advantage of mirror lock-up.

C.Fn III -18 – Continuous shooting speed

Although the EOS-1D Mark IV can shoot at up to 10fps, it doesn’t mean you’ll want to shoot that fast all the time. This Custom Function allows you to change the shooting rate of both the low speed continuous and high speed continuous speeds to match your needs. The high speed rate can be set between 2fps and 10fps while the low speed rate can be set between 1fps and 9fps.

C.Fn III -19 – Limit continuous shot count

With the EOS-1D Mark IV's ability to shoot at 10fps it's quite easy to shoot far more images than you need to. C.Fn III -19 allows you to limit the number of shots you can take in a single burst, helping to conserve memory card space and shoot only the images you need.

To make use of this Custom Function you need to register the maximum number of images you want to be able to capture and then enable the setting. One example may when trying to capture a golf swing – you can limit the number of shots fired to capture only the number of images you need to.

Custom Function Group IV – Operation/Others

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 that you can shoot static and moving subjects without having to change the AF mode.

There are five settings:

  • By default (setting 0) the Shutter button and AF-ON button both activate metering and start AF functions.
  • Setting 1 causes the shutter button to start metering and AF operation, while the AF-ON button acts as an AF Stop to pause AF operation.
  • Setting 2 is one of the most common choices. The shutter button will start exposure metering and the AF-ON button will start autofocus and metering.
  • Setting 3 is another common one, with the shutter button being used to activate AE lock and the AF-ON button starting metering and autofocus.
  • Setting 4 disables the AF-ON button and makes the shutter button start both metering and autofocus.

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, like 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, release the AF-ON button, recompose and shoot. Because the shutter button does not 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 – Quick Control Dial in metering

The Quick Control Dial fulfils a range of functions on the camera. However, when the metering is active the function of the Quick Control Dial can be changed.

By default the dial will control either exposure compensation or the aperture, unless C.Fn IV -5-1 is set in which case it will control exposure compensation or shutter speed.

There are five settings:

  • 1: AF point selection – this can be used to change AF points, without first having to press the AF point selection button. Unless C.Fn II -12-2 has been set, you will only be able to select single AF points in the horizontal plane. You will not be able to select vertical or auto point selection. For exposure compensation, you will need to press the +/- exposure compensation button and turn either of the command dials (Main Command Dial or Quick Control Dial).
  • 2: ISO speed – simply rotate the Quick Control Dial to change the ISO speed directly.
  • 3: AF point selection and +/-/AFpoint selection – this is the same as setting 1, but it also switches the function of the exposure compensation button and AF point selection button, such that pressing AF point selection and turning the Main Command Dial will act as exposure compensation.
  • 4: ISO speed and +/-/ISO – This works like option 2, but the functions of the exposure compensation button and ISO button are switched so exposure compensation is accessed by pressing the ISO button and rotating the Main Command Dial.
C.Fn IV -4 – 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 a choice from 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.

  • 0: Normal (disabled)
  • 1: White Balance
  • 2: Image Size
  • 3: ISO Speed
  • 4: Picture Style
  • 5: Record func + media/folder
  • 6: Menu display
  • 7: Image playback

If you have already set up Live View Mode or Movie shooting to be accessed from the SET button that setting will override any setting that’s made in this Custom Function.

C.Fn IV -5 – Tv/Av setting for Manual exposure

If you prefer to use the main dial to change the aperture when shooting in Manual mode, you can use C.Fn IV -5-1. By default, the main command dial adjusts shutter speed and the quick command dial adjusts aperture. C.Fn IV -5-1 switches these over.

C.Fn IV -6 – Dial direction during Tv/Av

Some photographers prefer the dials on the camera to work in the opposite direction, so rotating the Main Command Dial right in Av makes the aperture larger rather than smaller. To do this, you can reverse the dial direction using C.Fn IV -6-1.

If you activate this function in Manual mode both the Main Command and Quick Control dials will be reversed. In Tv and Av modes only the Main dial will be reversed while the Quick dial will function the same.

C.Fn IV -7 – Av setting without lens

This Custom Function has two settings:

  • 0: Disable – without a lens attached, you cannot pre-set and aperture to shoot with once you attach a lens.
  • 1: Enable – allows you to set an aperture without a lens attached. In studio photography where the aperture may already be determined, this will speed up your workflow.
C.Fn IV -8 – WB + media/image size setting

Usually, setting the WB and Image size, without entering the camera menus, is done on the small rear LCD panel after pressing the FUNC. button. This is the default, 0: Rear LCD panel setting.

Option 1: LCD Monitor allows you to makes these changes on the larger main rear LCD panel where they are easier to see. To move through each setting, press the FUNC. button. This setting will still work when shooting in Live View or Movie mode.

C.Fn IV -9 – Lock/mic button function

The protect/mic button on the EOS-1D Mark IV can be configured to do different things. This Custom Function has three settings:

  • 0: Protect (hold: Record memo). If you press the button, it will protect an image so that an image cannot be deleted. Holding the button for two seconds will allow you to record a voice memo attached to the image being displayed.
  • 1: Record memo (Protect: Disabled). Pressing the button will start voice memo recording. Releasing the button will stop the recording.
  • 2: Play memo (hold: Record memo). If you have a voice memo appended to an image, pressing this button will play the memo. Holding the button for two seconds will enter the memo recording function.

With settings 1 and 2, if you want to protect an image, you will need to use the menu function for image protection.

C.Fn IV -10 – Button function when rear command dial is OFF

The Quick Control Dial on the rear of the EOS-1D Mark IV can be turned off from the main On/Off switch so that you don’t accidentally knock the dial and change settings while moving around. If you have not activated the rear command dial, this Custom Function determines what each button does.

The default setting, 0: Normal, will allow all buttons to continue to function. Option 1: Disable, will also disable the main command dial, the quick command dial and the multi-controller – they will be unable to make any setting changes.

This setting may prove of interest to photojournalists who have to work in fast-paced environments where a camera swinging from your shoulder could easily change a setting by rubbing against your body.

C.Fn IV -11 – Start movie shooting

If you regularly shoot so that you combine stills and movie footage into multimedia presentations, it is likely you may want quicker access to the movie shooting mode.

By default (setting 0) you have to enter Live View Mode first. However, choosing option 1, Quick Start (<FEL> button), allows you to press the <FEL> button and immediately begin movie recording.

C.Fn IV -12 – Focusing screen

This Custom Function should be set to match the focusing screen you are using. The EOS-1D Mark IV 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.

The four settings are as follows:

  • 0: Ec-C IV – for the standard focusing screen.
  • 1: Ec-A, B, C, C II, C III, D, H, I, L – for laser matte screens.
  • 2: Ec-S – for super precision matte screens.
  • 3: Ec-N, R – for new laser matte screens.

C.Fn IV -13 – Timer length for timer

Various camera functions are stored in a timer memory after you have pressed a button. These include AE Lock, multi-spot metering and FE Lock. There is also a self-timer for the shutter release. There is a default setting for these times, but you can activate a 6sec timer for AE Lock, a 16sec timer for FE Lock and multi-spot metering. The timer after release is usually 2sec, but can be set from 0sec to 59sec in second increments, or from 1min to 60min in minute increments.

To make use of this, you need to 'Enable' it, 'Register' and 'Apply'.

C.Fn IV -14 – Shortened release time lag

The EOS-1 series DSLR cameras have a very short lag between fully pressing the shutter button and the shutter firing. However, some users may still prefer it to be quicker. If so, you can make use of C.Fn IV -14-1: Enable. As long as the lens aperture does not have to close more than three stops from the maximum aperture, the release lag can be reduced by up to 20%. For sports and photojournalists, this can be beneficial in capturing the moment.

C.Fn IV -15 – Add aspect ratio information

If you are shooting images to fit a particular aspect ratio, you can have guides displayed during Live View and Movie shooting, and the data appended to captured images for automatic cropping when in the Digital Photo Professional software programme. When shooting with this setting enabled, the whole image will be captured so you can change your mind later.

The seven setting options are:

  • 0: Off
  • 1: Aspect ratio 6:6
  • 2: Aspect ratio 3:4
  • 3: Aspect ratio 4:5
  • 4: Aspect ratio 6:7
  • 5: Aspect ratio 10:12
  • 6: Aspect ratio 5:7