Okii Systems USB Focus Controller User manual

Okii Systems LLC
809 Town Side Dr. • Apex, North Caro ina 27502 • USA
www.okii.net
[email protected]t
Introduction
The Okii Systems FC1 USB Focus Contro er (patent pending) is a battery powered, handhe d USB
host device designed to contro certain Canon EOS Digita SLR cameras that use Canon’s USB
protoco .
The FC1 USB Focus Contro er uses the motor in the ens to contro focus, even whi e recording
video. Additiona switches can be used to access important camera functions such as recording
start/stop, digita zoom to aid with focusing, engaging autofocus, saving focus points, and
adjusting certain camera settings.
For remote app ications, the FC1 USB Focus Contro er has been tested past 25 meters using
norma (non-powered) USB extension cab es. The HDMI output of the camera is not interrupted,
a owing you to use the FC1 USB Focus Contro er at the same time as an externa monitor.

2
Features
•Functions with Canon 1D Mark IV, 5D Mark III, 5D Mark II, 7D, 6D, 60D, 650D, 600D,
550D, and 500D
•Contro s focus by use of ens AF motor
•Starts/stops video recording
•Togg es ive view on/off
•Initiates image capture
•Initiates autofocus and metering
•Saves and returns to four focus points*
•Cyc es digita zoom 1x/5x/10x to aid in focusing
•Adjusts focus step size and focus command send rate
•Adjusts ISO, aperture, shutter speed, and exposure compensation
•Adjusts focus zone positioning
•30+ hour battery ife on two AAA a ka ine batteries
•¼”-20 mount on back p ate for rig mounting
•CNC mi ed from 6061 a uminum
•Approx. 4.7 oz (133 g) tota weight with inc uded batteries
•Made in the USA
*On certain enses on y. See the Controller Functions: Focus Points section of this manua
for more detai s.
Warranty
Okii Systems LLC warrants this product to the origina owner against materia defects for a period
of one (1) year from the origina date of purchase. Pursuant to this Warranty, Okii Systems LLC
wi , at its option, (i) repair the product, or
(ii) rep ace the product with a new or refurbished contro er. For purposes of this Warranty,
“refurbished” means a product or part that has been returned to its origina specifications.
This Warranty on y covers product issues caused by defects in materia or workmanship during
ordinary consumer use; it does not cover product issues caused by any other reason, inc uding
but not imited to product issues due to acts of God, misuse, imitations of techno ogy, or
modification of or to any part of the product, inc uding the software.
Okii Systems is not responsib e for inoperabi ity resu ting from changes to the camera firmware or
USB protoco instituted by Canon. Likewise, if the software on the FC1 USB Focus Contro er is
modified in any way, Okii Systems makes no express or imp ied warranties whatsoever with
respect to its functiona ity, operabi ity, or use.
A Return Merchandise Authorization number must be obtained from the Okii.net website prior to
returning any product for warranty service. Reimbursement wi not be made for service
performed by others. Un ess otherwise instructed, the product must be de ivered, freight prepaid,
in either its origina packaging or packaging affording an equa degree of protection to the faci ity
specified on the Okii Systems website RMA page. The origina sa es receipt must accompany a
warranty c aims.
The customer assumes a risk for the use of any Okii Systems LLC product, and is so e y
responsib e for determining its suitabi ity for use by any individua or app ication. Under no
circumstances sha Okii Systems LLC be he d iab e for damages resu ting from the use or misuse
of the product.

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Table of Contents
•Getting Started 4
•Canon USB Protoco 5
•Contro er Functions
oDiagram 6
oFocus Contro 7
oFocus Step Size and Live View On/Off 7
oDigita Zoom and Autofocus/Metering 8
oRecording Start/Stop and Image Capture 8
oModes 8
oFocus Points 9
oCamera Settings 10
oFocus Zone Contro 11
•Changing the Focus Command Send Rate 11
•Switch Test and Reversing Knob Direction 12
•Battery Indicator 12
•Disassemb y 13
•Reassemb y 13
•Troub eshooting 13

4
Getting Started
The FC1 USB Focus Contro er comes assemb ed with two AAA a ka ine batteries insta ed.
Before beginning, verify that your camera is a mode that is known to work with the contro er:
1DX • 1D Mark IV
5D Mark III • 5D Mark II
7D • 6D • 60D
650D/Rebe T4i/Kiss X6
600D/Rebe T3i/Kiss X5
550D/Rebe T2i/Kiss X4
500D/Rebe T1i/Kiss X3
An autofocus ens must be insta ed on the camera if you intend to use the contro er’s focus
features. Manua focus enses wi a so work, but you ose the abi ity to contro focus or use the
focus point functions. Canon USM or equiva ent autofocus enses are recommended — they tend
to be quieter, smoother and more consistent.
1. With the camera off, connect the contro er using a USB A to mini-B cab e. Turn on the FC1
USB Focus Contro er by s iding the power switch to the “on” position, away from the focus knob.
The LED indicator wi disp ay the current battery eve with a f ickering red, ye ow, or green ight,
fo owed by the contro er status:
Ye ow Camera disconnected or turned off
Green Camera connected, focus point mode
B ue Camera connected, settings mode
Purp e Camera connected, focus zone mode
Red Camera recording
2. Turn on the camera. The LED shou d change from ye ow to green, indicating that the USB
connection has been estab ished and the FC1 USB Focus Contro er is now in the focus point
mode.
3. If the ive view disp ay on the camera is turned on, you can adjust focus by turning the knob
or use any of the other functions described in the Controller Functions section of this manua .
Before using the FC1 USB Focus Contro er, fami iarize yourse f with setting the focus command
send rate described in the Changing the Focus Command Send Rate section of this manua .

5
Canon USB Protocol
Canon EOS digita SLR cameras use a combination of two protoco s ca ed Picture Transfer
Protoco (PTP) and Media Transfer Protoco (MTP) to send and receive commands, data, and
images to and from a computer using USB. Various projects, such as Canon’s own EDSDK, have
documented many of the USB commands that Canon uses. Okii Systems has a so reverse
engineered many of the commands specific to the FC1 USB Focus Contro er.
Canon’s imp ementation of USB has severa characteristics that direct y affect the performance of
the FC1 USB Focus Contro er:
1. When a focus command is sent to the camera, a success packet is a ways returned, even if the
command is ignored. The contro er can repeated y send focus commands, but if the camera is
performing another action, the focus wi not change.
2. There is no way to detect an ignored focus command other than seeing that the focus did not
move on the ens or in the ive view image. No USB feedback is given when focus commands are
ignored.
3. If the rate of commands is too fast, it can cause the camera to temporari y pause and ignore
further commands. The maximum re iab e rate is about 15 commands per second if the ens in
use is mechanica y ab e to move between focus positions at this speed.
4. The time it takes for each ens mode to change focus from one position to another varies,
depending on the type of ens motor, the foca ength, and the focus step size.
These characteristics make it necessary to adjust the focus command send rate to match the
foca ength of your ens and the focus step size. The process is described in the Changing the
Focus Command Send Rate section of this manua .
If a USB bus error occurs, Canon’s USB imp ementation ocks out externa input, making it
impossib e to send additiona commands. This can happen for many reasons such as corrupted
USB packets or overf owing the command/event buffers on the camera. If a bus error is
detected, the contro er wi disp ay a continuous f ashing red LED. Power cyc ing the camera and
contro er wi reso ve the issue.

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Controller Functions: iagram
The function of each switch is divided into short presses ( ess than ½ second), and ong presses
(ho d more than ½ second).
1. Short – cyc es sma /medium/ arge focus step size
Ho d – turns ive view on and off
2. Constant focus towards infinity
3. Constant focus towards minimum focus distance
4. Short – cyc es 1x/5x/10x zoom
Ho d – initiates autofocus or metering
5. Short – starts and stops video recording
Ho d – initiates image capture
6. Mu ti-function switch
a. Focus point mode:
Short – goes to near focus stop
Ho d – saves or c ears current focus stop ocation
b. Settings mode: Exposure compensation
c. Focus zone mode: Moves focus zone downwards
7. Mu ti-function switch
a. Focus point mode:
Short – goes to focus point
Ho d – saves or c ears current focus point ocation
b. Settings mode: Shutter speed
c. Focus zone mode: Moves focus zone eft
8. Mu ti-function switch
a. Focus point mode:
Short – goes to focus point
Ho d – saves or c ears current focus point ocation
b. Settings mode: Aperture
c. Focus zone mode: Moves focus zone right
9. Mu ti-function switch
a. Focus point mode:
Short – goes to infinity focus stop
Ho d – saves or c ears current focus stop ocation
b. Settings mode: ISO
c. Focus zone mode: Moves focus zone up

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Controller Functions: Focus Control
The focus can be adjusted by using the center knob or the two directiona focus buttons when
ive view is turned on. By defau t, turning the knob c ockwise wi cause the focus to move c oser.
Turning the knob counter-c ockwise wi cause the focus to move towards infinity. This matches
the focus ring rotation of Canon EF and EF-S enses. It is a so possib e to reverse the knob, which
is described in the Switch Test and Reversing Knob irection section of this manua .
If a continuous focus transition is desired, use either of the directiona focus buttons. Pressing
and ho ding either one wi cause the focus to continua y move toward the minimum focus
distance or infinity.
Important:
1. The maximum speed at which focus commands are sent is governed by the focus command
send rate. If the focus command send rate is set too fast, some focus change commands wi be
dropped, and the focus movement may be erratic. If this occurs, s ow down the focus command
send rate s ight y, then try again.
2. Each ens mode may require different focus command send rates for optima performance.
The focus step size in use wi a so have an impact: Large steps wi take onger for the ens to
move the focus because it has to turn further, so the rate must be s owed down.
To adjust the focus command send rate, refer to the Changing the Focus Command Send
Rate section of this manua .
Warning: Continuing to ho d a directiona focus button or turning the focus knob after a ens has
reached the end of its focus range may cause excessive wear on the autofocus motor. To prevent
this, use the near and infinity focus stops, which wi prevent additiona focus commands from
being sent once the focus reaches the saved positions. More detai s about using the focus stops
can be found in the Controller Functions: Focus Points section of this manua .
Controller Functions: Focus Step Size and Live View On/Off
Canon’s USB imp ementation a ows for three different step sizes when sending
a focus command to the camera. A short press of the focus step button cyc es through the three
different sizes. The LED wi b ink white one, two, or three times to indicate the sma , medium,
and arge step sizes.
Changing the step size wi have an effect on how ong it takes the ens to comp ete each focus
move, so the focus command send rate must be set appropriate y. Do not change the step size
after focus points have been saved, or you wi ose your focus point accuracy.
Ho ding the focus step button wi togg e the ive view disp ay on or off.
Note: The 7D and 500D/T1i/Kiss X3 ignore ive view “on” commands whi e in video recording
mode.

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Controller Functions: igital Zoom and Autofocus/Metering
If ive view is enab ed, a short press of the zoom button cyc es through 1x/5x/10x digita zoom,
which can be used to aid in focusing. Digita zoom does not work whi e recording is active.
Ho ding the zoom button wi initiate either the camera’s autofocus or metering
if not recording. You may se ect whether autofocus or metering is used in the Switch Test and
Reversing Knob irection section of this manua .
Using the camera’s autofocus wi cause any saved focus points to ose accuracy.
If you must use autofocus, do so before saving any focus points.
Controller Functions: Record Start/Stop and Image Capture
If the camera is in a video capab e mode, a short press of the recording button on the contro er
wi start or stop video recording. The contro er is synced to the camera and wi disp ay a red
LED the entire time recording is active. Recording can a so be started or stopped on the camera
body, and the contro er LED wi disp ay the appropriate co or.
Ho ding the recording button wi initiate an image capture if not recording video. This a so
functions if ive view is turned off or the camera is in a norma image capture mode. Even if
autofocus is enabled on the lens, it will not engage.
If you want to autofocus prior to capturing an image, be sure to first use the mu tifunction digita
zoom/autofocus button.
Note: When a sti image is being exposed, the contro er continua y monitors the camera for a
new fi e to be written to the memory card and disab es any other input. If no memory card is
present, the contro er wi wait the maximum exposure time, which is 30 seconds. It may appear
that the contro er is not responding, but it wi resume operation once 30 seconds passes. For
this reason it is recommended to a ways have a memory card inserted when using the image
capture function.
Controller Functions: Modes
The FC1 USB Focus Contro er has four mu ti-function buttons on the right side. The specific
function of these buttons changes according to the mode of the contro er. The LED disp ays one
of three co ors depending on the current mode:
Green Focus points
B ue Settings adjustment
Purp e Focus zone se ection
To change modes, press the top and bottom mu ti-function buttons at the same time (buttons 6
and 9 as abe ed in the Controller iagram section). The LED wi change co or when the mode
is switched.
The active mode is saved even if the contro er is turned off.
Note: Whi e recording, the LED a ways disp ays red, and the mu ti-function buttons revert to
focus points. When recording stops, the mode automatica y reverts to the ast one in use prior to
recording start.

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Controller Functions: Focus Points
When focus point mode is active (green LED), the mu ti-function buttons 6 – 9 are used to save,
c ear, and return to four focus points. Two of these are dynamic, whi e the other two act as focus
stops and wi not a ow the focus to trave past them:
Button 9: Infinity focus stop
Button 8: Dynamic focus point
Button 7: Dynamic focus point
Button 6: Near focus stop
Saved focus points are not retained through a power cyc e of the FC1 USB Focus Contro er, but
they wi be saved if the camera is disconnected or turned off whi e the contro er remains on.
A short press causes the LED to b ink ye ow and the focus to trave to a saved focus point. If
there is no saved point assigned to the button, nothing wi happen.
If no focus point is assigned to a button, a ong press wi save the current focus position and
b ink the LED purp e. A second ong press on the same button wi c ear the focus point and b ink
the LED red.
Once a focus position is saved with either of the focus stop buttons, the focus wi not trave past
the saved points. The infinity focus stop prevents the focus from trave ing further towards
infinity, whi e the near focus stop prevents the focus from trave ing any c oser. If either of the
dynamic focus points store ocations outside the bounds of the infinity and near focus stops, they
wi automatica y be c eared.
The two dynamic focus points do not prevent the focus from trave ing past them in either
direction.
Focus points can on y be saved or c eared when ive view is turned on and you are not recording
video.
Important: The focus points are saved on a command count basis, i.e., the contro er knows the
ocation of each saved position based on the number of commands it takes to reach them. If the
focus command send rate is set too fast, commands wi be dropped, and your saved focus points
wi not be accurate. Additiona y, if you do not set the infinity and near focus stops and continue
to turn the focus knob or ho d the directiona focus buttons after the focus reaches either end of
the focus range, your saved focus points wi no onger work.
Important: The use of the focus stops is significant — the contro er wi maintain the correct
count and accuracy, even if you continue to turn the focus knob or ho d a directiona focus
button after the focus has reached either stop. The contro er wi indicate a focus stop has been
reached by b inking the LED ye ow as ong as focus commands continue to be sent.
Important: Some enses suffer from focus point shift. For examp e, each increment towards
infinity focus may rotate the focus ring 15 degrees, whi e each increment towards near focus may
rotate the focus ring 10 degrees. This difference makes it a but impossib e to use focus points
re iab y. On y some enses suffer from this attribute, so test for this by saving two focus points
and repeated y transitioning between them.

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Warning: If you have saved focus points, the following may cause you to lose your
focus point accuracy:
1. Turning the focus ring on the ens by hand.
2. Changing the focus step size.
3. Setting the focus command send rate too fast.
4. Changing the foca ength of the ens (if using a zoom).
5. Initiating autofocus.
6. Continuing to turn the knob or ho ding a directiona focus button after the focus reaches
the end of the focus range, whi e not using the focus stops.
7. Using a ens mode with varying focus increments, resu ting in focus point shift.
Recalibration: If you have saved severa focus points but ost accuracy for any of the above
reasons, it is possib e to reca ibrate the ens without having to c ear/save the focus points again.
To accomp ish this, navigate to a saved focus point by pressing the appropriate button. Once the
focus stops moving, grasp the focus ring on the ens and turn it unti the ens focus corresponds
with the saved focus point.
Controller Functions: Camera Settings
When settings mode is active (b ue LED), it is possib e to adjust certain camera parameters, as
ong as the current y se ected shooting mode on the camera a so a ows it.
Mu ti-function buttons 6 – 9 are each used for a specific setting:
Button 9: ISO
Button 8: Aperture
Button 7: Shutter speed
Button 6: Exposure compensation
To change a setting you must press and ho d the assigned button, and then turn the knob to
increase or decrease the disp ayed va ue on the camera. The knob sensitivity is reduced whi e
changing a setting to make it easier to pick a new va ue. Once the new va ue is disp ayed on the
camera, re ease the button. The knob direction for each individua setting can be reversed.
Detai s on how to do this are in the Switch Test and Reversing Knob irection section of
this manua .
Note: Settings can on y be modified when recording is inactive. It is possib e to change certain
parameters whi e recording video by using the on-camera contro s, but the USB commands wi
be ignored due to Canon’s USB imp ementation.

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Controller Functions: Focus Zone Control
When the focus zone contro mode is active (purp e LED), you can move the focus rectang e by
using mu ti-function buttons 6 – 9:
Button 9: Moves the rectang e up
Button 8: Moves the rectang e right
Button 7: Moves the rectang e eft
Button 6: Moves the rectang e down
To re-center the focus rectang e, press buttons 7 and 8 at the same time whi e the digita zoom
is at 1x.
The focus rectang e position is not synced between camera and contro er, so using the on-
camera contro s fo owed by pressing buttons 6 – 9 wi cause the rectang e to reset to the ast
contro er issued position. Do not use both the on-camera contro s and buttons 6 – 9 at the same
time whi e moving the focus rectang e.
Changing the Focus Command Send Rate
The focus command send rate is one of the most important settings on the FC1 USB Focus
Contro er. It governs how quick y the focus can change, and a ows accurate and repeatab e
saved focus points. The defau t setting is 10 commands per second.
To enter the focus command send rate setting menu, the camera must be in focus point mode
(green LED) or settings mode (b ue LED). You then enter the menu by pressing multi-
function buttons 7 and 8 at the same time. The LED wi rapid y b ink purp e to indicate the
menu has started, and then disp ays a repeating sequence which shows the current command
send rate.
The sequence is made up of red and b ue LED b inks. Each red b ink indicates five commands per
second. Each b ue b ink indicates one command per second. For examp e:
1 red + 1 b ue b ink repeated = 5 + 1 = 6 commands per second
2 red b inks repeated = 5 + 5 = 10 commands per second
To increase or decrease the command send rate, press mu ti-function button 7 or 8. The LED wi
f ash purp e each time either button is pressed, and the b ink sequence wi show the new va ues.
To save the command rate and exit from the menu, press mu ti-function buttons 7 and 8 at the
same time. The contro er wi switch back to whichever mode you were in previous y.
The abi ity to save and return to stored focus points depends entire y on se ecting a command
send rate that is s ower than the minimum time required for the ens to switch between two
focus positions. If the command send rate is too quick, successive focus commands wi be sent
too fast and ost. This wi a ter the accuracy of the focus stops, and wi resu t in erratic motion if
you intend to use the directiona focus buttons or focus knob.
The focus command send rate is saved through a power cyc e, so there is no need to set this
each time you turn on the FC1 USB Focus Contro er.

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Switch Test and Reversing Knob irection
A diagnostic mode is bui t into the disconnected state (ye ow LED) of the FC1 USB Focus
Contro er. Pressing any switch by itse f or turning the focus knob wi cause the LED to start
b inking. This is a convenient test for a stuck switch or improper y insta ed button.
The knob rotationa direction can be reversed for focus contro and the settings mode for ISO,
aperture, shutter speed, and exposure compensation. This may be usefu if infinity and near
focus are switched on your third party ens, or if you want to match the rotationa direction on
your camera to change a setting. The knob directions can on y be modified whi e the FC1 USB
Focus Contro er is turned on and the camera is disconnected or turned off. The LED must show
ye ow to indicate the disconnected state.
To reverse the direction or change a button function, press and ho d the record start/stop button
(button number 5 on the diagram). The LED wi begin b inking ye ow. Press one of the fo owing
buttons to modify its function:
Focus step – button 1 Reverse focus direction
Mu ti-function – button 9 Reverse ISO
Mu ti-function – button 8 Reverse aperture
Mu ti-function – button 7 Reverse shutter speed
Mu ti-function – button 6 Reverse exposure compensation
Zoom – button 4 Togg e autofocus or metering
Each time the direction is reversed, the LED wi b ink red or b ue to indicate the change. The
zoom button’s ho d function can be switched to initiating autofocus (red LED) or metering (b ue
LED).
Knob directions and button functions are saved through a power cyc e, so there is no need to set
them each time you turn on the FC1 USB Focus Contro er.
Battery Indicator
As mentioned in the Getting Started section, the battery ife is shown with a f ickering red,
ye ow, or green LED when the contro er is first turned on:
Red Low battery
Ye ow Medium battery
Green Good battery
Additiona y, the battery eve is continua y monitored whi e the contro er is in use, and wi f ash
the LED red every five seconds when a ow battery is detected. This is viewab e in any contro er
state or mode except during active recording.
Typica battery ife with good qua ity a ka ine AAA batteries is approximate y 30 hours, depending
on usage. Lithium AAA batteries can extend this by another
10 – 15 hours. Once a ow battery eve is reached, approximate y one hour of run time remains.

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isassembly
Disassemb y of the FC1 USB Focus Contro er requires the use of a 1/16” and 5/64” A en wrench,
and a Phi ips screwdriver:
1. The back p ate of the contro er case is secured by two visib e Phi ips head screws. Removing
the back p ate wi expose the circuit board and AAA battery ho ders.
2. If further disassemb y is required, the knob must be removed. Use a 1/16” A en wrench to
oosen the set screw that secures the knob to the rotary encoder shaft. A fu turn shou d be a
that is necessary to s ip the knob off the shaft. Be carefu not to remove the set screw comp ete y
from the knob, as it can be easi y ost. Beneath the knob is a ny on washer, which can be set
aside.
3. Use a 5/64” A en wrench to remove the two board mounting screws ocated between the
battery ho ders. Once unscrewed, the entire circuit board can be ifted out. The LED ight pipe
and nine button inserts are now visib e and can be easi y removed.
Reassembly
Reassemb y is done in the reverse order:
1. Verify that the nine button inserts and LED ight pipe are insta ed.
2. Insert the circuit board into the case, ining up the power switch, rotary encoder, and USB
port.
3. Rep ace the two board mounting screws, making them snug.
o not over tighten!
4. P ace the ny on washer in the recessed groove on the underside of the knob.
5. Line up the knob set screw with the f at side of the rotary encoder, and then s ide it onto the
rotary encoder shaft.
6. Tighten the knob set screw unti snug.
7. Before rep acing the back p ate, verify that a the buttons work by turning on the contro er
and using the switch test mode. When no buttons are pressed and the knob is not moving,
the LED shou d disp ay so id ye ow. For each button pressed individua y, the LED shou d
start b inking.
8. If the LED b inks continuous y even though no buttons are pressed and the knob is
stationary, then one of the buttons is stuck. Disassemb e the contro er and correct the stuck
button.
9. Rep ace the back p ate and secure it with the two Phi ips head screws.
Troubleshooting
Many connection prob ems are caused by rapid y turning the camera or contro er off and on, as
this does not a ow the USB connection to proper y reset. For optima use and re iabi ity, a ways
give the contro er and/or camera severa seconds to fu y turn off or on before f ipping the power
switch again.
Controller displays constant blinking red LE .
This indicates a USB bus error. Turn off the camera, wait for the contro er to disp ay a ye ow
LED, then turn the camera back on.

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Controller does not turn on.
Verify condition of batteries and make sure the power switch is set to the “on” position (furthest
away from knob).
Controller does not recognize camera is connected.
Check that the USB cab e is secure y p ugged into both contro er and camera. Verify that the
camera works and the battery is charged. Make sure the camera is compatib e with the
contro er. If it sti does not work, disconnect the camera from the contro er and turn both off.
Pu the battery from the camera and wait 10 seconds, then rep ace. Reconnect the camera to
the contro er, then turn the camera on, fo owed by the contro er.
Camera displays error or is unresponsive.
Unp ug the camera from the contro er. Turn both off. Pu the battery from the camera and wait
10 seconds, then rep ace. Reconnect the camera and contro er, then turn the camera on,
fo owed by the contro er.
LE continuously blinks yellow when controller is turned on.
One of the switches is stuck. Press/re ease each one to find the stuck switch. It may be
necessary to disassemb e the contro er to fix the stuck switch.
Button presses seem difficult. Executing specific functions that require you to hold a
button don’t always work.
This indicates a stuck or defective button insert. Verify that a buttons work by using the switch
test mode bui t into the disconnected state (ye ow LED). Once the prob em switch is found, swap
the button insert with another switch ocation to see if this corrects the issue.
Focus points are not accurate.
Make sure the focus command send rate is not too fast for the specific combination of ens, focus
step size, and foca ength (if using a zoom). Changing the command send rate, focus step size,
or foca ength after saving focus points can affect the accuracy. Additiona y, some enses have
s ight y different increments if the focus moves from near to infinity versus infinity to near, and
wi not be accurate regard ess of contro er settings. This is a imitation of the specific ens.
Focus occasionally pauses or moves unevenly.
Make sure the focus command send rate is not too fast for the specific combination of ens, focus
step size, and foca ength (if using a zoom). If the command send rate is too fast, some focus
commands are dropped because the camera is busy executing the previous command. This gap
before the next command is received causes the focus to move uneven y. If you encounter
onger pauses when focus commands are ignored, the most ike y cause is that the focus
command send rate is too fast, creating an overf ow in the camera’s command buffer. You shou d
keep the focus command send rate be ow 15 commands per second.
Additional information is available at www.okii.net.