RadioPopper PX - Manual (Page 25)

Page 25
RadioPopper PX Radio Wireless System
PX Installation Trouble Shooting
Now let’s check the physical installation of your PX units on your Master and Slave flash unit(s).
1) On your Master flash, PX Transmitter should be oriented such that the small “bump” on the front (the signal pickup
sensor) is facing the same direction as the direction of light coming out of the flash. Please refer to Fig. 2.1, Page 13.
2) Make sure the window with the green circle on your PX Receiver (on the back side) is pointing directly into the signal
sensor of your slave flash. The proper location of this sensor is noted by the opening in the sticker supplied with Canon
mounting kits. On Nikon flash units, the IR sensor is the small black circle / window next to the battery door on your
flash. THE RED WINDOW ON THE FRONT OF YOUR FLASH IS _NOT_ THE IR SENSOR. The red window emits a focus assist
light and does not interact with the wireless flash function in any way.
3) For Canon mounting kits, be sure to remove the white center of the circle punched in the sticker. This center dot
should not be applied to the flash as it would block the signal from entering the flash.
PX Burst Mode and Crossed Signals
The PX system operates by “burst” radio transmission. Essentially, the PX Transmitter waits for a data signal to begin
emitting from your Master flash device. It then begins transmitting a packet of radio data including some coding used to
identify the signal and provide error correction. The PX Receiver sees this communication and begins to process it.
This processing time is extremely short, but it does cause the “Morse Code” blinks of light being reproduced by the PX
Receiver to emit very slightly delayed. If your Slave flash is able to “see” the line of sight IR signal coming from your
Master flash directly, then “sees” the signal being produced by the PX Receiver very slightly following, it may see two
copies of the same signal, slightly out of time with each other.
The PX Transmitter and PX Receiver are “smart” enough to quickly adjust this timing delay and catch the signal back up
to real time such that they are both perfectly in timing sync with each other before any instruction is given to actually
make light. Therefore, this timing delay has absolutely no effect on the timing of the pre-flash, ETTL/iTTL exposure
evaluation, high speed sync function, or the timing of the actual flash.
This Burst Mode makes it possible for multiple photographers to now control the same Slave flash unit in any of its
modes, as well as providing robust error correction, and it has no effect what so ever on the actual operation of your
wireless system. However, care must be taken in the mounting of your PX Receiver to your Slave flash to ensure reliable
operation.
Once your PX Receiver is properly mounted, this should not be an issue. It is generally only observable when shooting
the Master flash directly into the Slave flash at very close range, thus it is not a concern in normal operation.