Mobile phone flash external flash

20 18 12 15 "Flash synchronization of mobile phone photography"

The initial idea of mobile phone photography flash synchronization is that some mobile phone photography software is set to the volume button for synchronization operation, and the shutter acoustic signal is used to trigger the flash. But in practice, it is found that the shutter sound of mobile phone photography is always later than the actual shutter action time. After the deduction and practice of 1 year, the method of using the mobile phone flash with camera flash to trigger the studio flash is as follows:

Because the flash power of the mobile phone flash is extremely small, it is unrealistic for the flash of the mobile phone flash to directly trigger the studio flash with a distance of several meters to several tens of meters, so I designed a transit method as follows:

In the actual measurement, it is impossible for a camera flash with the size of a pill to be directly close to the flash window of a mobile phone (next to the camera of the mobile phone), so I designed to directly attach the photosensitive probe (photosensitive resistor) to the flash window with aluminum foil insulation tape. 1 is to make the photosensitive resistor (photosensitive probe) fully absorb the flash, and 2 is to prevent the flash from becoming interference light and affecting the flash photography. The specific method is as follows:

The life of a broken flash umbrella bulb is mainly due to the damage of the flash tube and the capacitor, while the photosensitive head (photosensitive resistor) that doesn't emit light on the other side of the flash tube opposite to the red light and the green light is basically not broken, so buy a broken flash umbrella bulb, remove the photosensitive probe (photosensitive resistor) the size of mung bean, connect a DIY flasher (RF remote controller is followed by a delay microswitch) and use the delay microswitch to flash and relay the RF remote controller. Because my low-grade 4-segment Yinhe brand studio flasher passively triggers the studio lamp, the measured data cannot trigger the same passive delay microswitch. The solution is as follows:

The delay microswitch is actively triggered by the RF remote controller at the legal standard frequency, such as 433MHz.

Total cost: If you buy multifunctional low-voltage (5V~30V) relay with LED digital panel (including multiple functions such as delay microswitch) and RF remote controller in an enterprise store, the total price of online shopping plus freight is around 50 yuan.

In addition, you can try to buy photoresistors online (note: the price is unknown, it should be very cheap, but you should pay attention to buying photoresistors that are sensitive to light, and the resistance will become very small immediately after receiving light), or you want to spend more money to buy a flash flasher of tens of dollars to remove the photoresistors, or you can connect a good flash umbrella bulb with a flash hole and remove the photoresistors when it is useless. In short, the photoresistor must be close to the flash window of the mobile phone to really flash, but I measured the photoresistor.

As for the delay time of flash start, the delay time of flash start is determined according to the shutter speed of flash photography (adjusted by user-defined ISO sensitivity), the resistance sensitivity and static (loss) current of photosensitive switch, the distance between RF remote controller and receiver, and the start delay of time delay relay.

Pay attention to insulation to prevent electrical short circuit. Because the passive trigger relay will have a slight spark in the pull-in mode, it should be far away from oil and gas sources, such as gas stations.

Summary: Practice is one of the criteria for testing truth.

Supplement: The camera software of Nubian NX403A mobile phone has not turned on the touch screen shooting function. Put the photosensitive head a few centimeters away from the flash of the mobile phone, so that the mobile phone can flash directly with the shooting flash without induction (startup). At this time, the delay of tens of yuan can be saved, and only the RF remote controller of 10-20 yuan can be kept. The measured flash synchronization is 1/8S. Other mobile phones and third-party shooting software that comes with non-mobile phones have not been tried.

Note: professional camera flash is a kind of RF remote control.