TTL Flash techniques for everyday photography

Nikon CLS Flash Techniques

If you are a Nikon shooter you should learn how to use Nikon CLS Flash techniques. CLS stands for Creative Light System. Nikon CLS makes flash photography more fun (provided that you know the techniques!)

Benefits of CLS

These are some of the most important features of Nikon CLS.

i-TTL: Monitor pre-flashes are emitted from a Speedlight before the main flash and reflected off every object in the frame. Monitor pre-flashes are picked up by either the five-segment TTL flash sensor or an RGB sensor. This information, along with data from the Matrix Metering System, is analyzed to adjust flash output for the most balanced background/foreground exposure possible. In other words, it gauges how far your subject is from you and then adjusts the power of the flash accordingly.

Auto FP High Speed Synch: This mode offers ample fill-in flash while shooting in bright conditions using a fast-aperture (smaller aperture number, larger opening) lenses, enabling effective blur in the background. Once this mode is activated, high-speed flash synchronization makes available shutter speeds that are faster than the camera’s own flash sync speed.

* Auto FP High Speed flash is not available with the D70s, D70, D60, D50, D40X, D40.

Flash Value Lock: With Flash Value Lock, you can obtain the correct exposure, when the subject is off-center and positioned against a dark or light background. Because the flash exposure remains locked-in even if you change the aperture or composition, or zoom the lens in and out, you can obtain the correct exposure for the main subject.

Without FV Lock, the main subject is overexposed due to the dark background

Flash Colour Communication: In Auto White Balance mode, the master unit attached to the digital SLR camera transmits flash color information to the camera. Voltage, flash duration and other variables can affect flash color information, so the camera uses data like this to achieve optimum white balance.

Distance-Priority in Manual Flash (SB-800 and newer): In this mode, the SB-800 and newer flashes automatically control the light output according to distance value and set apertures. Enter the shooting distance value and you can take pictures having the same exposure even when shooting at different apertures. This mode allows you to make exposure compensation by varying the flash output level compensation value

Modeling Flash: Press the Modeling Flash button and the flash will fire repeatedly at a reduced output level. This is useful for checking illumination levels and the shadows cast on the subject before actually taking the picture. The flash can fire up to approximately 3 seconds while the button is pressed.

Advanced Wireless Lighting: (This is our main subject in this class) Method of controlling multiple wireless flash units. The Master sends out a very small light pulse to provide the Remote and they communicate back subject exposure readings before the main exposure. Effective wireless range is 10m (33′) and 30 ° left or right of the Master at longest distance, 60 ° at closer distances.

• It is possible to separate i-TTL Speedlights into four groups comprised of the Master (SU-800, SB-800 can be used as a master to trigger remote units, SB-600 cannot be used as a master unit) and three Remote i-TTL Speedlight groups.

• Using the Master unit’s LCD you can set independent flash mode settings (TTL, Auto Aperture [Non-TTL Auto], Manual Repeating and Flash Cancel) and adjust flash output level compensation values independently for each group (A, B and C) and the Master unit (M).

• There is no limit to the number of Speedlights contained in each group.

• In Advanced Wireless Lighting, flash mode and other types of information are transmitted to each remote unit in the form of a series of low-level flashes from the Master unit. In TTL mode, the camera’s exposure metering sensor detects Monitor pre-flashes to determine each flash unit’s output level.

• The ability to adjust the flash output level of every flash unit from the camera gives you the freedom to experiment with a variety of settings much faster and more simply than with conventional systems. For convenience in pre-shooting lighting confirmation, use the Modeling Flash function.

Is Nikon CLS useful only for Off-Camera flash Photography?

Although controlling the Off-camera flash is one of the most powerful features of Nikon CLS, it changes the way you use your flash on camera as well. As an example, if you are shooting indoor with a Nikon camera and Nikon flash, your camera measures the ambient light and will tell the flash how much light it needs to make a balanced picture. Which results in to a very natural looking image.

As you can see in this sample, the ambient and flash light are very well balanced.

Another good example fro Nikon CLS is the HSS or High-speed Shutter Synch, which allows you to shoot at any shutter speed even over the synch speed.

These are few advantages of Nikon CLS Flash Techniques. If you want to learn more, please register for  Flash Photography Workshop. It is a two part workshop and scheduled for May 13 and 14. We will cover TTL technology for all cameras.