SB-900 - CLS Master
To set the SB-900 to Master mode, press and hold the power button and rotate the switch to the 'MASTER' position.
The LCD will now display the Master Setup, and allow you to set the operating mode for 4 individual groups. These are the Master SB-900 and 3 independent Remote groups known as A, B and C.
Which mode you choose will depend on what and where you are trying to shoot. A brief discussion of the different modes is available here. Within each group you can also set FEC (Flash Exposure Compensation), or in Manual mode set the exact power output of each Group individually.
The SB-900 operates in a very simple easy to use way. You 'Select' something, then you 'Change' it, so to change anything, you must first 'Select' it.
Selecting the Channel
Before you do anything else, make sure that the Master and Remote flashes are on the same Channel! The Nikon CLS also provides 4 different channels so that up to 4 photographers can use CLS in close proximity without accidentally triggering each other's Remotes.
In order to trigger a Remote speedlight, the Master and Remote speedlight must be set to the same channel. A Master set to Channel 1 will only trigger Remote speedlights that are also set to Channel 1. A Master set to Channel 2 will only fire Remotes set to Channel 2, and so on.
To select the Channel on the SB-900 in Master mode first select the Ch button, the press the Ch button again, or use the command dial to cycle through channels 1 to 4 until the desired channel is displayed, then press the OK button.
Once the Channel has been selected, each Remote speedlight needs to be set to a 'Group'. To see how to set a Remote speedlight Group, see one of these links: SB-900 Remote, SB-800 Remote, SB-600 Remote, SB-R200 Remote.
Master Mode Group Selection
A Master SB-900 can control up to 3 remote Groups, designated as A, B and C. Group M is this Master flash.
To select a Group press the SEL (Select) button until the desired group is highlighted.
In this example the 'M' group is currently selected, so any changes to the Mode or FEC will effect the only the 'M' group. Each time the Select button is pressed it will advance to the next group.
Once a group is selected the settings for that group can then be changed as required, without effecting any other Group
Setting the MODE for each group
With the required Group selected, press the MODE button to highlight the Mode for this Group. In this example the M group is selected and the Mode (A) is currently highlighted. Press the MODE button again to cycle through the available modes until the desired mode appears. Each time the MODE button is pressed the Mode for this Group will change to the next Mode in the sequence. Alternatively rotate the command dial to cycle through the available Modes.
The available modes are:
Once the required Mode has been selected, press the OK button to confirm the change, or press the SEL button to move to the next group. Pressing the SEL button confirms the last change and moves to the next group with a single button press.
A description of each of the modes, and when each mode should be used is available HERE.
Flash Exposure Compensation (TTL & A Modes)
From time to time you may want to increase (or decrease) the amount of light coming from one or more Groups, yet still retain a high level of automation. This is achieved by adjusting the exposure compensation value on a Group by Group basis.
With the group highlighted in TTL or A mode, press the +/- function button once to highlight the EV value, then press the +/- button again, or turn the command wheel to cycle through the possible settings. Once the required value is displayed, press the OK button.
In TTL & A mode, the possible values are:
(Reduce Output) -3.0, -2.7, -2.3, -2.0, -1.7, -1.3, -1.0, -0.7, -0.3, (Standard Exposure) 0, (Increase Output) +0.3, +0.7, +1.0, +1.3, +1.7, +2.0, +2.3, +2.7, +3.0.
Note that it may not always be possible to provide the amount of compensation requested. For example, if the flash is already running close to full power it will not be possible to add 3.0 to the final output, and care should be taken to ensure that underexposure (or less exposure that expected) may doesn't occur. Where insufficient power is available, alternatives need to be found.
Setting Power Output in Manual Mode
If the group is set to M mode (Manual), The flash will output the same power each time, and not rely on real time metering functions. This is similar to using regular studio strobes.
To set the power output for each group, select the M button to select & highlight the power setting, then press the M button again, or turn the command dial to select the fixed power output.
For SB-900 & SB-800 models the available output range is from 1/1 (full power) down to 1/128. This is the equivalent of 7 stops of power range!
Setting the Aperture in A Mode
Aperture mode should only be used with bodies that do not support i-TTL.
With the channel highlighted, and the Mode set the A, the third function button will become an FNo option. This allows you to preset the Aperture value for the Group. Pressing the FNo button selects the F stop indicator, then pressing the FNo button again (or rotate the command dial) to select the required F stop setting.
To set the ZOOM position
With the wide angle diffuser open, or when the diffuser dome is attached, the ZOOM position is automatically set to 14mm and cannot be changed. This is ideal for covering large areas, or filling a large umbrella.
However, with the wide angle adapter retracted and diffuser dome removed, the widest zoom position is 17mm and the longest zoom position is 200mm.
To set the zoom on this flash head press the ZOOM button to highlight the ZOOM setting, then press the ZOOM button again, or turn the command dial to cycle through the available zoom positions, press the OK button. The available settings on an SB-900 are: 17mm, 18mm, 20mm, 24mm, 28mm, 35mm, 50mm, 70mm, 85mm, 105mm, 120mm, 135mm, 180mm and 200mm.
Disabling the SB-900 Flash in Master Mode
Press the SEL function button until the M is highlighted at the top left of the display, then press the MODE button to select the operating mode or turn the command dial until the mode shows '---'. This effectively disables the main flash output for the SB-900. The same can be done for any of the Groups. Simply set the group to '---' to disable it.
Caution - Master Disabled - or not?
There appears to be some confusion on many internet forums about whether the SB-900 will emit it's own flash during the actual exposure time, even when disabled. In fact the SB-900 does fire during the exposure, even when disabled, because it uses visible (not infra red) light to communicate with the CLS Remotes. The amount of light that is emitted is much lower than a normal flash, and provided the subject is a reasonable distance away it is unlikely to have much (if any) effect on the exposure.
However, if you are positioned close to the intended subject (i.e. taking shots of something on a light table) even this small amount of flash can easily be seen in the resulting exposure. If you have a lens hood fitted, you may also see a shadow when the lens hood obscured the path of the flash.
So, how do you work around this? The easy answer is to rotate the head to point upwards and/or away from the subject. If this is is not working for you, check out the SU-800 CLS Commander, which does not have a built in flash head.
So, Now what?
Your SB-900 should now be set up ready to go. You should ensure that your Remote speedlights are set to the same channel as the master, and that each has their Group set appropriately. To see how to set up Speedlights in Remote mode, check out the following links.
Setting the SB-900 as a CLS REMOTE
Setting the SB-800 as a CLS Remote
Setting the SB-600 as a CLS Remote