Digital Photography Tips and Techniques

Nikon CLS Advanced Wireless Lighting is actually very capable. It handles all the functions you can do with a Nikon Speedlight attached to the camera’s hot shoe except the RPT flash. Specifically, Flash Value (FV) lock, FP high speed sync, modeling flash all work seamlessly. It even works when you use mirror-lockup function on the camera. In the part V of the series, we will look at the FV lock function.

Flash Value (FV) Lock

When you push the FV lock button (on my D200, I assign the FUNC button to FV Lock), the camera will initialize the pre-flash sequences to determine the flash output amount for all groups involved. Then you can recompose and take a photo without causing incorrect exposures for off-center subject. This is fairly straight forward in regular TTL flash mode but more complicated in wireless lighting setup due to the extra communication requirements. To illustrate the flash sequence when FV lock is used in Advanced Wireless Lighting, I use a simple example in which Master (a Nikon D200 in Commander mode) is set to TTL mode and remote group A is also set to TTL mode. I first pressed the FV lock button, then pressed the shutter release button all the way down ~1 second later. Read More…

After going through the boring parts of the series (Part I, Part II, Part III), in which I described the “secrets” of Nikon CLS Advanced Wireless Lighting, I will discuss some real world examples this time using Nikon CLS Advanced Wireless Lighting. The examples are intended to show some of the common issues people may have seen.

To run the test, I mounted a SB-800 Speedlight on one end of the Nikon SC-28 TTL Remote Cord, then mounted them on a light stand using the 1/4″ thread of the SC-28. If I connect the flash to the camera’s accessory shoe, I can use the available flash modes offered by SB-800, such as TTL/BL, TTL, etc. I can also disconnect the cable from Camera and set the flash as a remote unit that I can control using the camera’s built-in flash as master. This setup allows me to run the test without moving either the flash or the camera. Read More…

In the first two parts (Part I, Part II) of the Nikon CLS Advanced Wireless Lighting series, I have showed many examples of the pulse communication sequences but didn’t go into details about them. In part III, I will discuss the detailed coding scheme used by Nikon CLS Advanced Wireless Lighting system.

From the previous examples we know that there are several command types the master flash unit emits to control the remote flash units. To avoid interference, the optical pulse sequences start with a channel indicator so only remote flash units belong to the specified channel react to the commands. This channel indicator always contains 3 pulses. After examining the distances between pulses, I found that all the distances are results of a unit distance multiplied by integers, except for the channel indicator pulses, which contains 1x, 1.5x, and 2.5x unit distances between pulses. It appears that the optical wireless communication uses a hybrid coding scheme. After the channel indicator, the pulses confirm to simple binary format, pulse for “1″, no pulse for “0″. So it is quite easy to figure out what’s going on. Read More…