AI Servo AF Custom Function ISO Speed Settings Guide
AI Servo AF Custom Function & ISO Speed Settings Guide
AI Servo AF Custom Functions
Custom functions for personalized AI Servo AF settings to capture moving subjects more effectively
The EOS-1D Mark IV offers photographers a variety of options to customize AF and Continuous shooting operation. These can be found in the third Custom Function group (C.Fn III). Among the Custom Function options are those that can be set for a variety of subjects when using AI Servo AF which is the best AF mode for moving subjects. As introduced on page 4, the Custom Function settings provide a greater level of versatility for a wide variety of shooting situations. Depending on the shooting conditions, it is possible for the AI SERVO AF mode to focus more accurately on fast moving subjects by selecting an appropriate Custom Function. This guide describes the features of these key Custom Functions, and how to select and use the most appropriate settings.

ISO Speed Settings

A wide range of normal ISO speeds (ISO 100 12800) and ISO expansion options (ISO 50, 25600, 51200, 102400) are available
A major feature of the EOS-1D Mark IV is its outstanding image quality at high ISO speeds. Image quality improvements brought about as a result of the newly developed 16 megapixel CMOS sensor and Dual "DIGIC 4" image processing make it possible to use a maximum standard ISO speed of 12800, with an ISO expansion of up to ISO 102400. Until now, images at ISO speeds of 3200 and 6400 were of such a quality that usage was generally due to the need for an image rather than a desire to have the best possible image quality. With the EOS-1D Mark IV, image quality has improved so much that the normal ISO range up to 12800 is now suitable for a much greater range of photographic situations. The second half of this guide introduces the superior image quality of the EOS-1D Mark IV including use of high ISO speeds, and offers tips for getting the best results at all ISO speed settings.
AI Servo AF 4 Default Settings: Basic Settings with the Greatest Versatility Notable New Custom Functions 6 [C.Fn III-6] Pinpoint Focusing with Spot AF 8 [C.Fn III-11] Switch to Registered AF Point Instantly Applies Preselected AF Points 10 C.Fn III-16] Orientation-Linked AF Point Selection Switches Focusing Points Automatically When [ Changing Between Vertical and Horizontal Camera Positions Important Custom Functions for AI Servo AF 12 [C.Fn III-2] Tracking Sensitivity: Use Intermediate Slow for Fast Moving Subjects 14 [C.Fn III-2] Tracking Sensitivity: Use Slow For Subjects that Appear and Disappear Intermittently 16 C.Fn III-8-1] AF Expansion with Selected Point: Capture Subjects with Fast Side to Side Movement by [ Selecting Left/Right AF Point Expansion 18 C.Fn III-8-2, C.Fn III-8-3] AF Expansion with Selected Point: Capture Subjects with Rapid Movement by [ Selecting Surrounding AF Point Expansion 20 [C.Fn III-4-0] AI Servo AF Tracking Method: Continuously Follow One Subject with Main Focus Point Priority 22 C.Fn III-4-1] AI Servo AF Tracking Method: Shift Focus to Foreground Subject with Continuous AF Tracking [ Priority 24 C.Fn III-3] AI Servo 1st/2nd Image Priority: Determine the Relationship between AF Operation and Shutter [ Release During Continuous Shooting 26 utual Association of Important C.Fn: How Camera Operation Will Change When Combining C.Fn III-2, 4, M 8 Special Hints for Sharp Photos 28 ollecting Predictive AF Data for 0.5 Seconds Before Shutter Release Raises the Probability of Accurate C Focusing 30 Using AF Point Expansion to Prevent Mistakes with Focus Shifting to the Background 32 sing AI Servo AF Tracking Method to Prevent Focus Shifting to Obstructions in the Foreground U 34 Deal with Slightly Out of Focus Photos from Minor Shaking with Even Faster Shutter Speeds ISO Speed Settings 36 Normal ISO Speeds of ISO Achieve High Image Quality 38 ISO Expansion from ISO Adds a New Dimension to Shooting 40 Image Quality at Each Setting with High ISO Speed Noise Reduction 42 Auto ISO Function is Useful for Shooting Conditions with Great Differences in Contrast 44 Confirming How to View Noise at High ISO Speeds with Print Size 46 Low ISO Speed Expansion ISO 50 can be Useful for Shooting Expression 47 Various Custom Functions that can be Applied to Shooting

AI Servo AF Default settings
The basic settings have great levels of versatility and can handle a wide variety of shooting opportunities and subjects
Custom Functions related to AI Servo AF are included in the C.Fn III AF/Drive group.
The default out of the box settings are the simplest settings and are more than capable of handling shooting for a variety of subjects.
EOS-1D Mark IV Custom Functions related to AI Servo AF are included in the C.Fn III AF/Drive group. This group's default Custom Function settings are the basic settings for AI Servo AF. Basic Settings are the most general settings, capable of handling the majority of shooting conditions. The Custom Functions that will be introduced later, when set for specific conditions can raise the probability and precision of focusing. However, when the settings are not appropriate, the probability and precision of focusing may actually be reduced. AI Servo AF on the EOS-1D Mark IV uses a new AF algorithm, and the tracking performance of moving subjects has been significantly improved. So, first try shooting with just the default settings and none of the Custom Functions selected. Then after considering the shooting conditions try setting the Custom Functions for even higher consistency and precision of focusing.
Photo taken with the default settings, and not using any of the C.Fn III AF/Drive Custom Functions. This setting will get the best possible performance when shooting subjects that generally do not move. EF400mm f/2.8L IS USM 1/2000 sec. f/2.8 ISO100

Setting hints

When even more stability is required than that provided by the Default Settings, using the options within C.Fn III-8 (AF expansion),and C.Fn III-4 (AI Servo AF tracking method) are also effective
Default settings are the easiest to use, however, when you want to consistently capture subjects that move extremely quickly, C.Fn III-8 AF expansion, and C.Fn III-4 AI Servo AF tracking method: Option 1 (Continuous AF track priority) will be effective. Refer to the description pages (pp. 16, 20).
AI Servo AF Notable function
Custom Function C.Fn III-11
Switch to Registered AF Point
You can instantly shoot with a different registered AF point
Registered points can be applied with one button
Manually selected AF point
Switch to registered AF point Press the Multi-controller once, or
While pressing the AE lock button
In the manual AF point selection mode select the desired AF point, by pressing the AF point selection button. Once the required point has been chosen, then press the ISO button, the AF point will then be registered and this is confirmed by a beep.

The 45-point AF system on the EOS-1D Mark IV makes it possible to capture the subject within a wide area. However, when shooting sports where the players move around quickly, switching from a manually selected AF point while shooting can be difficult. In situations like this, Custom Function C.Fn III-11 Switch to registered AF point is useful. This function allows instant switching to a previously registered AF point with just one button. Registration of AF points can be carried out during normal shooting conditions by manually selecting the AF point, then while pressing the AF point
selection button, press the ISO button to register. Then when C.Fn III-11 is set to option 1 or 2 switching to the registered AF point is possible. Because it is possible to switch the AF point with just one button, while shooting with a manually selected AF point on the left edge, it is also possible to instantly switch and shoot with a registered AF point on the right side. This function is convenient for registering an AF point that is frequently used.
* With the C.Fn III-6 option, when lenses with an AF stop button are attached, selection of registered AF point with the AF stop button is possible.
EF300mm f/2.8L IS USM 1/1600 sec. f/2.8 ISO3200 In order to capture the skater on the right hand side while shooting with a manually selected AF point on the left hand side, this photo was shot by switching to a registered AF point on the right. This feature is effective for shooting sports where there is a lot of leftright, right-left movement.
It is possible to instantly switch between two AF points
Switch to registered AF point
EF300mm f/2.8L IS USM 1/1600 sec. f/2.8 ISO3200
For illustrative purpose, all AF points are displayed superimposed.
Orientation linked AF point selection
Three AF Points with differing orientations can be set
Automatically switch between set AF points for each different hold
Vertical position, with grip on top

Horizontal position

Vertical position, with grip on bottom Different AF points can be set to three orientations. Changing the orientation of the camera will automatically switch to the preset AF point
Set C.Fn III-16 Orientation linked AF point to Option 1: Select different points, and then while holding the camera in each orientation, carry out the AF point registration.

With the EOS-1D Mark IV, it is possible to select individual AF points according to the camera orientation (horizontal position, vertical position with grip on top, and vertical position with grip on bottom) for the AF points. First, select C.Fn III-16 Orientation linked AF point Option 1: Select different AF points, then while holding the camera in each different orientation, select each AF point. Then, by switching back and forth between horizontal and vertical positions, the preset points
will automatically switch according to the orientation. By using this it is possible to shoot in rapid succession without button operation, additional moving from the horizontal position with the AF point on the right, to the vertical position with the AF point at the top. This function is effective for shooting subjects where changes in framing are required.
Automatically switch AF points between the vertical and horizontal positions
Shoot with the set AF point in the vertical position (center of the screen), then right away in the horizontal position shoot when automatically switched to the AF point at the top right of the screen. By using AF point selection for each orientation, this kind of shooting is possible.
For illustration, all AF points are shown at once.
Custom Function C.Fn III-6-7

Spot AF

Pinpoint focusing is
Spot AF narrows the operating area of the AF sensor
EF200mm f/2L IS USM 1/1000 sec. f/2.8 ISO3200
Spot AF can be used by selecting Custom Function C.Fn III-6 Lens/Stop Button Function for setting: 7 Spot AF. (Illustration is the AF sensor during AF. Actual length not displayed.)
Among the EOS-1D Mark IV AF functions, a new function that stands out is Spot AF. This function narrows the operation area of each individual AF point. As focus can be attained on a smaller area of the image, it can be effective when used in situations like sports when aiming at
players through a net, or when attempting to focus on the eyes of a race driver wearing a helmet. (When using a normal line sensor, the probability of focusing on a net in the foreground or on the edge of the helmet is higher, this will make it possible to focus on the main subject at the back.)
* This function can only be used when lenses with an AF stop button are attached.
Lens AF stop button on large-diameter single focal length telephoto and super-telephoto lenses
Spot AF can be activated on supertelephoto L-type IS lenses by pressing and holding the AF stop button after C.Fn. III-6 AF stop button function has been set to option 7: Spot AF setting.

EF400mm F2.8L IS USM

EF300mm F2.8L IS USM

During Normal

During Spot AF

C.Fn III-4

Use Continuous AF track priority when tracking one person during area expansion
Subjects in the foreground will be treated as obstructions with this setting
Main focus point priority
Use C.Fn III-8 AF Expansion with selected point as described on the previous page, and when shooting extremely fast moving subjects, another important Custom Function is C.Fn III 1-4 AI Servo AF tracking method (hereafter tracking method). Basically, when you want to track one subject using area expansion, it is best to set the tracking method to option 1: Continuous AF track priority (hereafter continuous priority). When shooting with area expansion and using this setting, if another subject comes into the foreground, it will be treated as an obstruction by the manually selected AF point (the center of the area expansion). Results of focusing are used to detect the position of the subject, and AF points switch from one to the next within the expanded AF points to capture the subject. With shooting situations like this, when using area expansion to shoot moving subjects, the continuous priority setting is effective in almost every situation. When there is no specific target, as we will introduce on the next page, it is probably best to remember, if area expansion is used, use C.Fn III-4 option 1: Continuous AF track priority.
When shooting sports with a variety of shooting situations with setting C.Fn III4 AF tracking method option 1: continuous priority selected, it will be easier to focus-track the targeted player.
EF300mm f/2.8L IS USM 1/500 sec. f/2.8 ISO1600
EF400mm f/2.8L IS USM 1/4000 sec. f/5.6 ISO200 Continuous priority
In cases where an obstruction cuts into the foreground, and the AF tracking method is set to option 0: Main focus point priority, focus can shift to the obstruction resulting in a missed image. If it is set to Continuous priority, it will continuously track the subject.
AI Servo AF tracking method 2
Shift focus to the subject in the foreground with Main focus point priority
Effective for extremely fast moving subjects and sports with random movements

5th image
When shooting in continuous mode with AI Servo AF, Custom Function III-3 AI Servo 1st/2nd image priority can determine whether shutter release timing is controlled by the camera or the photographer. When AF Priority is selected for the first frame, the camera controls shutter release timing based on focusing data. If Release Priority is selected, then the photographer controls shutter release timing for the first frame. If Tracking Priority is selected for subsequent frames during continuous shooting, the camera will control shutter release timing based on AF data. If Drive Speed Priority is selected for subsequent frames, the camera will fire at the framing rate selected by the photographer regardless of the focusing
conditions. There are four combinations of AF or Release Priority for the first image, and Tracking or Drive Speed Priority for subsequent images. You can select the option for your requirements depending on whether you want priority on focus-tracking or shutter release timing. In normal shooting conditions, there will be no extreme differences no matter what the setting is. However, in conditions such as low light where autofocusing takes more time, please note that the probability of accurate focusing may be lower in some cases if Drive Speed Priority is selected.

C.Fn Mutual association

C.Fn III-2/C.Fn III-4/C.Fn III-8 relationship
With AF point expansion, choices of AF tracking methods will change
AF expansion with selected point
AI Servo tracking sensitivity
AI Servo AF tracking method
III-8 Area expansion and III-4 Tracking method
Two types of AF tracking methods during area expansion
III-8 AF point expansion 0: Main focus point priority Subject that entered the foreground With Enable III-4 AI Servo AF tracking method Available Tries to focus as fast as possible
1: Continuous AF track priority Subject that entered the foreground Disregard

With Disable

III-4 AI Servo AF tracking method Not available
Other than the reaction time to when a subject comes into the foreground, for both options 0 and 1, the AF tracking method will be set according to the option for tracking sensitivity (the same as Area expansion set to Disable).
The three important AF related Custom Functio ns introduced up to now, C.Fn III-2 Tracking Sensitivity, C.Fn III-4 Tracking Method, and C.Fn III-8 AF Point Expansion are associated such that each of their settings exert an influence on the workings of the other functions. For example, if AF point expansion is turned off, the AI Servo AF
tracking method will not function. Regardless of which C.Fn III-4 setting is used, the C.Fn III-2 setting [AI Servo tracking sensitivi ty] generally takes priority. However, if another subject blocks the main subject when the C.Fn III-4 setting is 0, the camera refocuses on the new subject regardless of the C.Fn III-2 setting.

III-8 Area expansion, III-4 Tracking method, and III-2 Sensitivity
There are three cases for the three C.Fns related to AI Servo AF operation

Case 1

When C.Fn III-4 option 0: Main focus point priority is selected and the selected AF point detects a new subject, the camera quickly focuses on that subject.
The C.Fn III-4 Tracking method function is always available when C.Fn III-8 AF point expansion is active. With this combination, the way the AF points show up, and the speed at which focusing occurs can change depending on the specific settings and is subject to the conditions at that time. When Main Focusing Point Priority is selected and a new subject is detected, the AF point showing the fastest response is used first, even if it is not the manually selected focusing point. Focusing control reverts to the manually selected focusing point as soon as possible if the movement of the subject allows it. Case 2

AF point selection

Assist AF points of the expanded area
Regardless of the C.Fn III-4 Tracking Method setting, if there is an AF point within the expanded area that should be used, control will quickly transfer to that focusing point.
When conditions differ from case 1, and the camera determines that the AF point should be Case 3 transferred within the area, it quickly transfers to that AF point and carries out focusing.
When neither Case 1 nor Case 2 applies, AF operation is carried out according to the Tracking Sensitivity settings
When the conditions in both case 1 and case 2 do not apply, AF operation according to C.Fn III-2 Sensitivity is prioritized (For example, if Slow is selected, focus will not quickly shift to the background even if the subject moves away from the expanded area AF points.)
* New subject refers to a subject that the manually selected AF point lands on that is closer than the subject that was tracked up to that time.

Special Article

Requirements for sharply focused photos
Reliably raise the probability of focusing the first image by tracking the subject for 0.5 sec. before the shutter is released
When the shutter button is fully pressed with no predictive computation When the AI Servo AF is not in operation, a photo of a moving subject is taken by suddenly pressing the shutter button fully.

Avoid Focus

The first image may not be focused in some cases When the shutter button is pressed suddenly, it will be difficult to accurately focus the first image

Shooting with C.Fn III-4 Tracking Method Option 1: Continuous AF tracking priority Shooting the same scene with C.Fn III-4-1 keeps the focus on the main subject instead of the obstruction.
Continuous focus on the subject was made possible As objects cut in front of the primary subject will be viewed as obstructions, mistakes with focus on the obstructions can be avoided.
Motion blur can be suppressed by utilizing faster shutter speeds
EF200mm f/2L IS USM 1/500 sec. f/4 ISO3200
Photos that look sharp at a glance, however
Viewed at 100% on a computer screen you can see it is slightly blurred
When viewed initially there is very little cause for concern, however, when viewed at 100%, an image that is slightly blurred could be caused by the use of a shutter speed that is too slow to stop the action.
Often the cause of this is not focus, but rapid subject movement
Countermeasures for minor camera shake visible at 100% display
Minor motion blurs can be suppressed with high speed shutter speeds of 1/1000 and 1/2000 sec.
EF200mm f/2L IS USM 1/2000sec. f/2.8 ISO6400
Camera shake thoroughly suppressed with faster shutter speeds In order to suppress minute camera shake that is visible when images are viewed at 100%, daring to use fast shutter speeds like 1/2000 sec. can be highly effective. Take advantage of the higher ISO speed image quality and strength of the EOS-1D Mark IV, use the fast shutter speeds.
When an AI Servo AF photo of a moving subject is viewed on a computer display and the photo seems to be slightly unsharp, it is incorrect to assume that a focusing issue is always the cause of the problem. Even in photos shot with a fairly fast shutter speed, the lack of sharpness could be a result of subject movement or camera shake. This is particularly relevant to the EOS-1D Mark IV because even small levels of motion blur are noticeable at 100% magnification due to the cameras 16.1 megapixel resolution. First, determine whether the sharpness problem is caused by poor focusing, camera shake or subject movement. If it is camera shake or subject movement, an effective countermeasure is to use a faster shutter speed. Up to now, if you thought increasing the shutter speed by one stop was sufficient to eliminate motion blur, try increasing the shutter speed by two steps and then shoot the photo.

ISO speed settings

ISO image quality
The EOS-1D Mark IV achieves low noise and high image quality even at high ISO speeds
From ISO100 - ISO12800 it is possible to set the EV value of the ISO speed from 7 stops up to the desired ISO speed level.

With High ISO speed reduction set from Disable to Standard, the number of shots during continuous shooting will not change. When set to Strong, there will be a noticeable drop in the number of shots during a continuous shooting burst.
EF24-105mm f/4L IS USM f/4

Disable

Standard Standard

Strong

The appearance of high ISO speeds on the EOS1D Mark IV are the result of an advanced image sensor and image processing technology. The Custom Function C.Fn II-2 High ISO speed noise reduction setting is set to a default setting (option: 0) of Standard. In order to get an idea of the noise reduction function effects, you should compare photos taken with ISO speeds of ISO1600 ISO6400
or higher by changing Noise Reduction from Disable to Strong. You will be able to see that approaching high ISO speeds of ISO12800, when set to Disable, noise will become more visible. Even at extremely high ISO speeds, if Standard and Low noise reduction are working, noise will be considerably reduced.

Auto ISO

With the ISO speed set to A (ISO Auto), when using manual exposure it is possible to shoot continuously with the same aperture and shutter speed
In the ISO speed settings, turn the dial from ISO100 (default setting) to the left to display A and set ISO Auto.
Aperture f/2.8 1/1000 sec. (ISO800)
Aperture f/2.8 1/1000 sec. (ISO400)
Shooting with manual exposure using the Auto ISO setting The exposure mode is set to Manual, the desired aperture value and shutter speed are set, and shooting is carried out.
As introduced on P 36, the EOS-1D Mark IV has an extremely wide range of normal ISO levels from ISO100 - 12800. By using this wide range of normal ISO speeds and ISO Auto, it is possible to shoot continuously with the same aperture value and shutter speed going from bright locations to dark locations. By simply selecting "A" in the ISO speed settings, the ISO Auto setting will be activated.
Next, the exposure mode is set to Manual, the desired aperture value and shutter speed are set, and then shooting is carried out. Shooting begins in a bright location, and as the camera is directed toward a darker location, shooting takes place with the ISO speed increasing automatically. This method is effective when you want to continuously shoot with a certain aperture value and shutter speed setting.

EF70-200mm f/2.8L IS USM 1/1000 sec. f/2.8 ISO Auto
Aperture f/2.8 1/1000 sec. (ISO320)
Shooting takes place with the same aperture value and shutter value and only the ISO speed will change It was possible to photograph the athlete continuously from a bright location to a dark location with no changes to the aperture at f/2.8 and shutter speed at 1/1000 sec.
Relationship of noise and print size
Confirm the noise appearance at the actual printing size (magnification)

420 mm 420 mm

297 mm
Actual size sample of printing at A4 size two-page full-sized (420 x 297 mm)
Actual size sample of printing at approximately of an A4 page (210 x 148 mm)
4 x 4 cm section of each displayed ISO1600 A B

ISO6400 A B

An increasing amount of attention is being paid to the image quality of digital SLR cameras, in particular in reference to the noise at high ISO speeds. So, when photos are printed, how will the noise and image quality appear in printed materials? There should be a visible difference in the noise and image quality when confirming an image is magnified (at 100% display on a monitor), compared to the actual print size used. Here we have placed high ISO speed images from
an EOS-1D Mark IV, shown at the magnification of two popular printed sizes used in magazines. You will notice the image quality of EOS-1D Mark IV images at high ISO speeds with a lack of visible noise, however, at actual printing sizes, you will notice that image quality even at low ISO speeds compares favorably. Use these photos as a reference when deciding your own standard ISO speeds.

ISO3200 A B

ISO12800 A B
EF24-105mm F4L IS USM f/8
Taking advantage of ISO 50 (L)
Using lower shutter speeds, aim for creativity by making use of low ISO speeds
Using C.Fn I-3 Set ISO speed range, with the minimum value registered to L, it is possible to set ISO50 (L).
At ISO50 the shutter speed is set 1 stop down and panned
With the EOS-1D Mark IV, in addition to ISOnormal ISO speeds, it is possible to use 3 stops for the higher ISO speeds (ISO25600 102400), and 1 stop for the lower ISO speeds (ISO50) as ISO expansion. To use low ISO speed ISO50, it is necessary to register the minimum low ISO speed setting L with Custom Function C.Fn I-3, the same as with the high ISO speed options. With the lower ISO speed ISO50, compared to
ISO100, it is possible to set a 1 stop slower shutter speed, or a 1 stop brighter aperture value. Due to this, when you want to pan with a slow shutter speed in comparatively bright conditions, or shoot with a blurred background in the same bright conditions with the lens towards maximum aperture, setting to ISO50 can be effective. When set to ISO50, compared to ISO100, note that highlight areas can be more easily blown out.

A variety of Custom Functions that can be applied to shooting

C.Fn -14

Apply shooting/metering mode [Setting:1 Enable]
EF300mm f/2.8L IS USM 1/1250 sec. f/2.8 ISO100 (Manual exposure) EF300mm f/2.8L IS USM 1/1000 sec. f/2.8 ISO640 (Shutter-priority AE)
While shooting in manual exposure, large differences in brightness or contrast are dealt with by applying auto exposure This function can be useful in scenes where you primarily want to shoot with manual exposure, but you need to be able to deal with cases where the subject suddenly moves into dark or bright areas. Set C.Fn I-1 Apply shooting/metering mode to option: Enable, and auto exposure (Aperture priority AE for example) will be registered. With this option set, while shooting in Manual exposure mode, the camera will switch to the registered auto exposure mode only when pressing the AE lock button. If the subject moves into a dark or bright location, the appropriate auto exposure can be carried out. When the subject returns to the original lighting conditions, manual exposure mode can be restored by releasing the AE lock button. This setting is effective while shooting locations with great differences in brightness or contrast.
With C.Fn I-14 using Register you can register the exposure mode, metering mode, shutter speed, aperture, and exposure compensation amount to the camera, and you can instantly apply any of these with the AE lock button.

C.Fn -3

Quick Control Dial in metering [Options: 1 or 3 AF point selection]
Using the Quick Control Dial while shooting can be an effective way of moving the AF point While continuously shooting moving subjects, it is difficult to instantly switch the AF point to the desired location. As introduced on pp. 8 11, the registered AF point function is one useful function for switching AF points during continuous shooting. Also, when you want to move the AF point horizontally, options 1 and 3: AF point selection of C.Fn IV-3 Quick Control Dial in metering is also effective. By using these settings, while metering is active it is possible to move the selected AF point left and right with the Quick Control Dial. As the Quick Control Dial is easy to operate during continuous shooting, carrying out extremely fast horizontal movement of the AF point while shooting is possible.

By setting C.Fn IV-3 Quick Control Dial in metering to option: 3 AF point selection, horizontal movement of the AF point using the Quick Control Dial is possible.