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Technische Daten

Dieser Artikel ist leider nicht verfügbar auf Deutsch
July 2007

To ensure you get the best results from any camera it is important that, before using it on a shoot, you get to know how it works. The EOS-1D Mark III is no exception and it has a plethora of customisation options to suit the way you like to use your camera and the subjects you shoot.

Here we take a look at the Custom Functions relating to AF performance and drive (Custom Function group III) showing what each setting does and when you might use it.

  C.Fn III Related Settings
1 USM lens electronic MF C.Fn IV-1
2 AI Servo tracking sensitivity  
3 AI Servo 1st/2nd image priority  
4 AI Servo AF tracking method Auto AF point selection, C.FN III-8
5 Lens drive when AF impossible Lens focusing distance limit switch
6 Lens AF stop button function  
7 AF Microadjustment  
8 AF expansion with selected point C.Fn III-4
9 Selectable AF point  
10 Switch to registered AF point C.Fn III-6-6
11 AF point auto selection C.Fn IV-3
12 AF point display during focus  
13 AF point brightness  
14 AF-assist beam firing Flash C.Fn
15 Mirror lockup  
16 Continuous shooting speed  
17 Limit continuous shot count  

Naming conventions: The custom functions on the EOS-1D Mark III are grouped into categories to make it easier to locate and change the settings. The naming follows the convention shown below:
E.g. C.Fn III-4-1
III denotes the custom function group, in this case group III for Auto focus/Drive
4 denotes the custom function within that group
1 denotes the setting applied to that custom function

The Custom Functions in group III

C.Fn III-1 – USM lens electronic MF

Possible settings:
  1. Enable after One-Shot AF
  2. Disable after One-Shot AF
  3. Disable in AF mode

After focus is achieved with the USM lens in the One-Shot AF mode, manual focusing or full-time manual focusing can be used.
By using manual focus after focus is achieved with a USM lens in the One-Shot AF mode, you can adjust the focus manually. For this, set it to “0.” Or you can use full-time manual focusing with the USM lens, in which case you have to set C.Fn IV-1-2 or C.Fn IV-1-3 to enable the AF Start button to operate the AF.
Be aware that the electronic manual focusing ring is very sensitive to enable highly precise focusing. With setting “1” or “2”, you can prevent the focusing ring from turning inadvertently.


The 85mm f/1.2L II USM lens uses electronic focus. C.Fn III-1 allows you to activate or de-activate manual focus after AF depending on the shooting situation.

This C.Fn is for use with the following lenses:

Enable after One-Shot AF

  • 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
  • EF28-80 f/2.8-4L USM

Example situation and usage:

With the “0” setting and a USM lens with electronic manual focusing (see the box above for a list) such as the EF85mm f/1.2L II USM, when shooting portraits you want to compose the shot then focus on the person’s eyes. However, if there is no AF point covering the eyes, you can autofocus with an AF point covering the face and then use manual focus to focus on the eyes.

This custom function setting depends on the setting of C.Fn IV-1: Shutter button/AF-ON button which will enable or disable the electronic manual focusing as shown in the table below.

    C.Fn IV-1
  Setting 0, 1, 4 2, 3
  0 O / X O / O
C.Fn III-1 1 X / X X / O
  2 X / X X / X
  : Full time manual focus

After focus achieved / After focus failed
O: Enabled X: Disabled

C.Fn III-2 – AI Servo tracking sensitivity

Possible settings:

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.

Example situation and usage:
The slow setting is recommended for sports such as slalom skiing or breaststroke swimming. In the case of the slalom skiing, the skier zigzags between poles while racing down the hill. When the skier passes a pole, the pole will be in front of the skier and could distract the AF. However, with the sensitivity set to low, the AF will continue to track the skier without being distracted by the pole.
The breaststroke swimmer presents similar problems as the head rises out of the water and then dives below constantly providing obstructions to the AF. If you try to shoot the face of the swimmer above the water, you can lose focus tracking when the head is submerged in the water. With the slow setting, you can continue to track the face while ignoring the water surface and water splashes as obstructions. If the swimmer stays submerged too long, the camera may still switch to focus on the water surface. If this does happen, stop the AF and try again.

The standard setting is recommended for shooting sports such as figure skating or moving trains and other vehicles.

Figure skating includes both fast and slow movements as the skater is in time with the music. There is a wide range of movement for which the standard setting will provide the best compromise for both the fast and slow movements. With the fast setting, the camera will be more likely to switch to focus on the background if the skater escapes the AF point.

With the fast setting, the camera will switch quickly to another subject if the current subject is lost. It requires much skill to keep tracking the same subject with the focusing points, especially if the subject movement is fast and erratic. You should only set the fast setting for fast-moving, large subjects like trains that are easier to track and cover with AF points. If the subject is small and the camera is set to ‘Fast’, the camera will tend to focus on the background or obstructions when it loses track of the target subject.

C.Fn III-3 – AI Servo 1st/2nd image priority

Possible settings:
  1. AF priority/Tracking priority
  2. AF priority/Drive speed priority
  3. Shutter release priority/Drive speed priority

For AI servo shooting, you can adjust the priority for the 1st shot or the 2nd 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).

1st shot:
With AF priority (C.Fn III-3-0 or C.Fn III-3-1), a fixed period of time is allotted for focusing (the lens-driving time). Focus does not need to be achieved to take the shot, but with more time to achieve focus, priority is given to achieving focus. With Shutter release priority (C.Fn III-3-2), pressing the shutter button completely will take the shot even during focusing.

2nd and subsequent shots:
With tracking priority (C.Fn III-3-0), more time will be given to tracking the subject. This is effective in low-light or low contrast situations which are harder to track with autofocus. If the tracking sensitivity is low and it is hard for the autofocus system to track the subject, the continuous shooting speed from the 2nd shot will become slower to give priority to subject tracking.
With drive speed priority (C.Fn III-3-1), the continuous shooting speed from the 2nd shot is given priority. Depending on the subject, the camera might not attain the top continuous shooting speed.
With drive speed priority (C.Fn III-3-2), the continuous shooting speed from the 2nd shot is given more priority that in C.Fn III-3-1. Depending on the subject, the camera might not attain the top continuous shooting speed.

Example situation and usage:
C.Fn III-3-0 is useful for car races. Since race cars move very quickly, if the lens cannot track the race car quickly, it will not achieve correct focus. From the 2nd shot on, priority is given to subject tracking instead of continuous shooting speed to give the camera more lens-driving time.

C.Fn III-3-1 is best suited to sports like football and sports at night. In low light, the lens requires more time to achieve focus so for the first shot, priority is given to gaining focus. For the second and subsequent shots, priority is given to shooting speed to capture the moment.

C.Fn III-3-2 is recommended for press photography where capturing the decisive moment is important. At this setting, the focus may be slightly off, but the moment is captured. However, if the subject brightness or contrast is low, AF might not be possible (the focus confirmation lamp will blink in the viewfinder). Sometimes, setting “0” or “1” may be better if you are not working in a fast pace environment.

C.Fn III-4 – AI Servo tracking method

Possible settings:
  1. Main focus point priority
  2. Continuous AF track priority
This custom function requires two other settings:
  • Automatic AF point selection
  • AF expansion with C.Fn III-8
C.Fn. III-4-0 “main focus point priority” will differ as follows on these settings:
  • With automatic AF point selection, the selected AF point will be used
  • With AF expansion, the selected AF point will be used. (The AF point at the centre of the left/right Assist AF points or the AF point at the centre of the surrounding Assist AF points).

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) 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.

Example situation and usage:
With main focus point priority, the AF point shifting will work in the same way as the EOS-1D Mark II N’s AI SERVO AF.

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-4 helps in situations like this where you want to keep the focus on the main subject rather than jumping to a new subject that appears in the foreground.

The same is true of a downhill slalom skier. When the skier turns behind the pole, the camera will ignore the pole as a distraction and will, by selecting a different autofocus point, keep track of the skier.


Switching on the AF expansion points (C.Fn III-4) has stopped the AF system jumping from the skier to the slalom pole despite the motion of the skier.

With continuous AF track priority, if you change the target subject during AF, the camera might see the new target as an obstruction. If this does happen, stop the AF operation and then re-start. The camera will immediately recognise the new target subject.

C.Fn III-5 – Lens drive when AF impossible

Possible settings:
  1. Focus search on
  2. Focus search off

If the camera cannot achieve focus, it can present a very out of focus view through the viewfinder while it searches (‘hunts’) through the focusing range. Setting C.Fn III-5-1 will stop this happening by stopping the AF search function when focus cannot be achieved.

Example situation and usage:
When using lenses such as the super telephoto EF500mm f/4L IS USM, it can be difficult to track a subject such as a bird flying. If the bird escapes the AF point, the sky can cause the AF to hunt through the focusing range trying to find focus. Setting this custom function to 1 will stop the lens hunting and make it quicker for you to re-acquire focus.

An alternative would be to set the focus distance limit switch to avoid the lens hunting through the entire focus range. This will also help reduce gross out-of-focus situations.

C.Fn III-6 – Lens AF stop button function

Possible settings:
  1. AF stop
  2. AF start
  3. AE lock
  4. AF point: M -> Auto/Auto -> Centre
  6. IS start
  7. Switch to registered AF point

The action of the AF Stop button on lenses such as this EF500mm f/4L IS USM can be customised to suit your needs with C.Fn III-6

The AF Stop buttons are the four black buttons around the front of certain Image Stabilised super-telephoto lenses. This custom function allows the changing of the role of these buttons to suit your preferences or the conditions. This custom function will be ignored if a lens without AF stop buttons is attached to the camera.

0: AF stop - While you hold down the lens AF stop button, the AF operation is suspended.

1: AF start - While you hold down the lens AF stop button, the AF operates.

2: AE lock - When you press the lens AF stop button, AE lock is set. (Same function as the AE lock button.)

3: AF point: M -> Auto/Auto -> Centre - When you press the lens AF stop button, the AF point selection mode changes. (After automatic AF point selection, pressing the lens AF stop button selects the centre AF point.)

4: One-Shot AF <- > AI SERVO - When you press the lens AF stop button , the AF mode changes.

5: IS start - While you hold down the lens AF stop button, the Image Stabilizer operates. (It will not operate if the IS switch on the lens is off.)

6: Switch to registered AF point - While you hold down the lens AF stop button and press the FE lock button, the camera switches to the registered AF point. If you again hold down the lens AF stop button and press the FE lock button, the camera will switch back to the previous AF point.

C.Fn III-7 – AF Microadjustment

Possible settings:
  1. Disable
  2. Adjust all lenses by the same amount
  3. Adjust each lens individually

AF Microadjustment is for users who wish to modify the AF focusing precision. Instead of returning the camera to a Canon Service Centre for adjustment, you can do the fine adjust of the point of focus yourself.
As standard, the AF precision is adjusted in both the camera and lens so that it falls within the lens depth of focus (an area inside the camera at which the light rays are focused). If you use this custom function and adjust it wrongly, it will be impossible to attain correct focus.

C.Fn III-7-0 – No AF Microadjustment
C.Fn III-7-1 – The same focus shift adjustment amount will be applied to all lenses. This is effective if the camera’s focus is out, but the lens focus is not.
C.Fn III-7-2 – The focus-shift amount will be applied to the specific lens model. This is convenient if you want to shift the focus for a particular lens.

Specifying the Lens Model Name – When using AF Microadjustment, be aware that some lenses with a I or II designation will be recognised as the same lens. The table below shows which lenses.

For lenses which can be used with an Extender 1.4x or 2x, the camera will recognise them separately compared to the lens without the extender attached. For example, an EF300mm f/2.8L IS USM lens will be treated differently to an EF300mm f/2.8L IS USM with an Extender EF1.4x Mark II attached. Although the camera distinguish between the EF300mm f/2.8L IS USM and the EF300mm f/4L IS USM, it cannot distinguish between two different models of a lens, for example two different EF300mm f/2.8L IS USM lenses will be treated as the same.

Example situation and usage:
AF Microadjustment provides very precise adjustment of the AF focus precision. If the camera develops a focusing problem and there is no Canon Service Centre nearby, you can perform an AF Microadjustment as an emergency measure. You can then, when near a Service Centre, take the camera in for proper adjustment.

To make the adjustment, mount the camera on a solid tripod, take a picture and check the focus. Make an adjustment and re-check. Repeat this until you are happy with the focusing precision. As a general guide, one notch on the adjustment scale is 1/8 of the depth of field at lens’s maximum aperture. And the adjustment range is ±20 steps. Adjusting towards the front will result in a closer point of focus, towards the rear will obtain a farther point of focus.

Lens Model Name as recognised by AF Microadjustment Lens Model Name
EF28-70mm f/3.5-4.5 EF28-70mm f/3.5-4.5
EF28-70mm f/3.5-4.5 II
EF200mm f/2.8L USM EF200mm f/2.8L USM
EF200mm f/2.8L II USM
EF28-80mm f/3.5-5.6 EF28-80mm f/3.5-5.6
EF28-80mm f/3.5-5.6 II
EF28-80mm f/3.5-5.6 USM EF28-80mm f/3.5-5.6 USM
EF28-80mm f/3.5-5.6 II USM
EF28-80mm f/3.5-5.6 III USM
EF28-80mm f/3.5-5.6 IV USM
EF28-80mm f/3.5-5.6 V USM
EF28-105mm f/3.5-4.5 USM EF28-105mm f/3.5-4.5 USM
EF28-105mm f/3.5-4.5 II USM
EF75-300mm f/4-5.6 USM EF75-300mm f/4-5.6 USM
EF75-300mm f/4-5.6 II USM
EF75-300mm f/4-5.6 III USM
EF75-300mm f/4-5.6 EF75-300mm f/4-5.6
EF75-300mm f/4-5.6 II
EF75-300mm f/4-5.6 III
EF28-90mm f/4-5.6 USM EF28-90mm f/4-5.6 USM
EF28-90mm f/4-5.6 II USM
EF28-90mm f/4-5.6 EF28-90mm f/4-5.6
EF28-90mm f/4-5.6 II
EF28-90mm f/4-5.6 III

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

Possible settings:
  1. Disable
  2. Enable (left/right Assist points)
  3. Enable (surrounding Assist AF points)

Example situation and usage:
Focusing and following a puppy, bird or other fast-moving subject can be tricky and requires a lot of skill. Using an expanded AF point can help track such fast moving subjects. It should be used with caution though as if you were shooting a ball rolling along the grass for example, the camera could easily focus on the grass in front of the ball instead of the ball itself.
The setting of this custom function should be determined by the size and speed of the subject as well as whether there are likely to be obstructions or not.

C.Fn III-8-1 broadens the selected focusing by one point either side.
C.Fn III-8-2 creates a ‘ring’ of AF points surrounding the selected AF point which is ideal for subjects without a lot of detail or in low-light conditions.

C.Fn III-9-1 – Selectable AF point

Possible settings:
  1. 19 points
  2. Inner 9 points
  3. Outer 9 points

If you find you never use the inner or outer focusing point respectively, you can use this custom function to disable them and make focus point selection quicker. Combing C.Fn III-9-1 or C.Fn III-9-2 with C.Fn IV-3-1 allows instant changes with the quick control dial (no need to press the AF point selection button first), and instant return to Centre AF point if the multi-controller is pressed straight in.


C.Fn III-10 – Switch to registered AF point

Possible settings:
  1. Disable
  2. Enable

By registering your favourite AF point, you can instantly switch from any AF point to the registered AF point. You can switch to the registered AF point only during metering. This is similar to C.Fn 18 on the EOS-1D Mark II and Mark II N.

To register an AF point, select the AF point, then hold down the AF point selection button and press the ISO button. HP will appear on the top LCD panel to inform you that you have registered a ‘Home Point’.

There are then two methods to access your registered home point instantly:
  1. Press the multi-controller directly inwards. (To return to your previous AF point, press the multi-controller inwards again)
  2. Hold down the lens AF stop button, then press the FE lock button. Repeat the procedure to return to the previous AF point. To use this method, you must first set C.Fn III-6-6.

C.Fn III-11 – AF point auto selection

Possible settings:
  1. Quick Control Dial direct:disable/Main Dial:enable
  2. Quick Control Dial direct:disable/Main Dial:disable
  3. 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.

This C.Fn 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.

You can enable or disable the Quick Control Dial from switching to automatic AF point selection during metering as per the following table.

Setting Automatic AF Point Selection
0: Quick Control Dial direct:disable Disable
1: Quick Control Dial direct:disable Disable
2: Quick Control Dial direct:enable Enable

You can also enable/disable the Main Dial from switching to automatic AF point selection when you are selecting the AF point. See the table below:

Setting Automatic AF Point Selection
0: Main Dial:enable Enable
1: Main Dial:disable Disable
2: Main Dial:enable Enable

When automatic AF point selection is disabled, the automatic AF point selection display will not appear.

C.Fn III-12 – AF point display during focus

Possible settings:
  1. On
  2. Off
  3. On (when focus achieved)

The AF point display during focusing is different depending on the One-Shot AF/AI SERVO AF mode and automatic or manual AF point selection mode.

If you don’t like the red focus point illumination this custom function allows you to set whether you would rather it only showed briefly (C.Fn III-12-2) or not show at all (C.Fn III-12-1). Option C.Fn III-12-1 also eliminates red AF point illumination when using automatic AF point selection with One-Shot AF.

The table below shows the differences when used with either One-Shot AF or AI SERVO.

Setting One-Shot AF/Automatic Selection One-Shot AF/Manual selection
0 Displayed when focus achieved Always displayed
1 Not displayed Not displayed
2 Displayed when focus achieved Displayed when focus achieved
Setting AI SERVO AF/Automatic selection AI SERVO AF/Manual selection
0 Not displayed Always displayed
1 Not displayed Not displayed
2 Not displayed Displayed only when AF starts

C.Fn III-13 – AF point brightness

Possible settings:
  1. Normal
  2. Brighter

Set this if you want the AF point display in the viewfinder to be brighter. When the AF point is brighter, you can see the AF point display even under direct sunlight. Also, it can help you see the AF point better when you are tracking a fast-moving subject in AI SERVO AF mode.

C.Fn III-14 – AF-assist beam firing

Possible settings:
  1. Enable
  2. Disable

When emitting the AF-assist beam is not suitable, such as group photo sessions, you can disable the EOS-dedicated Speedlite’s AF-assist beam. In low light, it might be difficult to focus without the AF-assist beam, but there should be no problem under normal lighting levels. Note that the AF-assist beam is only emitted in One-Shot AF mode and not in AI SERVO AF mode regardless of the setting of this custom function. It will also not be emitted if the camera determines there is sufficient light to focus.

Example situation and usage:
At a group photo session with other photographers and one model, it is possible that when your focus beam is emitted, it could be recorded in the image of another photographer shooting at the same time. To prevent this, set C.Fn III-14-1.

Effect of Speedlite Custom Function
The table below shows what happens when this custom function is combined with the Custom Function for AF-assist beam on a compatible Speedlite.

  Camera Speedlite AF-assist beam
C.Fn setting Enabled Enabled Emitted
Enabled Disabled Not emitted*
Disabled Enabled Not emitted
Disabled Disabled Not emitted

* If you have an EOS-dedicated Speedlite which does not have a Custom Function for the AF-assist beam, use the camera’s custom function to disable it.

C.Fn III-15 – Mirror lockup

Possible settings:
  1. Disable
  2. Enable
  3. Enable: Down with SET button

Using mirror lockup prevents vibrations from mirror movement causing camera shake which degrades image quality, especially with telephoto and macro lenses. With C.Fn III-15-1, the mirror will raise on the first press of the shutter button, then return to the normal down position after the image is taken with the second press of the shutter button. If the picture is not taken within 30 seconds of the mirror being raised, it will return to the down position to protect the shutter blades from heat caused by focused light rays hitting them.
To shoot continuously with mirror lockup, set C.Fn III-15-2. This will keep the mirror locked up for as many images as required. To return the mirror to the normal ‘down’ position, press the SET button.

During mirror lockup, the mirror lockup icon will be displayed on the top of the LCD panel as shown in the picture below:


C.Fn III-16 – Continuous shooting speed

Possible settings:
  1. Disable
  2. Enable
  3. Register

This custom function allows you to set a desired maximum shooting speed for both high-speed frame advance (2fps-10fps) and low-speed frame advance (1fps-9fps). These can be set in 1-fps (frame per second) increments. The set fps for the high-speed continuous shooting must be faster than that set for the low-speed continuous shooting.

Example situation and usage:
To capture something regular such as a golf swing, you could use a faster frame rate – to see exactly what happens during the swing, or a slower frame rate to capture fewer frames and show more change between them.
This setting can also be useful if you want to shoot continuously but don’t need the maximum 10fps. By setting a lower fps, you can shoot more images in a sequence before the buffer fills and ‘Busy’ is displayed on the LCD panel.

Even with the maximum fps of 10 set, there are situations when that cannot be reached:
  • A slow shutter speed is used
  • A small aperture is used
  • AI SERVO AF is used and the subject moves in a way that takes the lens longer to focus
  • The subject is dark or has low contrast
  • The maximum burst for continuous shooting has been reached and the buffer is full.

C.Fn III-17 – Limit continuous shot count

Possible settings:
  1. Disable
  2. Enable
  3. Register

There may be times when shooting that you do not want to shoot until the buffer is full. You can limit the maximum burst using this custom function to prevent excessive shooting. This will help save on image storage space and review/edit time needed later on the computer.

Example situation and usage:
In conjunction with C.Fn III-16, you could limit the number of shots taken to match the period of time required to capture an entire golf swing.