People love photography related hacks and DIY projects. The most popular ones are related to photography lighting such as light modifiers, special lighting equipments, etc. If you want to sample just some of the things you can do, has a pretty good list of things you can try.

Here are the couple of things I have been playing with lately. If you have noticed reduced posting frequency on this blog, that’s part of the reasons. 🙂

TTL flash output controller

If you read our post about the duration of flash you will know the amount of the flash output is controlled by the duration of the flash. When the flash such as the Nikon SB-600 is mounted on a camera’s hot shoe and the system is set to operate in TTL mode, the camera tells the flash how much light it emits via electrical signal communication between the camera and flash. The communication protocol is proprietary information.  To maintain backward compatibility though, the flash in TTL mode can also work in a simple way: Just like you turn on a light, wait for a while, then switch it off. Obviously we need a circuit to do this in a much faster way.

If you look at the flash shoe on a Nikon DSLR camera, you will see something like this (image credit

The flash starts to fire when the sync contact (X) is shorted to the ground and stops the flash when the quench contact (Q) is shorted to ground. The simple DIY circuit below does just that. An Arduino Duemilanove I/O board is used to control the flash duration. The precision of the flash duration is about 1 microsecond or 1/1000000s.

Hacking flash

Nikon wireless flash controller

Nikon Creative Lighting System (CLS) supports Advanced Wireless Lighting (AWL). I was able to decode most of the communication protocol by recording the light pulses using a photodiode connected to a computer sound card (Part I, II, III, IV, V). What the simple setup below does is quite simple: it records the light pulses from the wireless flash commander then replays the signal via a LED when a button is pushed. The signal from the LED is very weak so the effective distance is only about an inch!

Hacking flash, II

Smart optical trigger

If you try to use a flash with a simple optical flash trigger mixed with Nikon flashes in AWL setup, you will run into trouble because the flash will fire upon seeing the first light pulse from the pre-flashes. The setup below is an optical trigger that cannot be fooled by the monitor pre-flashes sent from wireless commander. It also works in non-wireless TTL mode where the flash on camera still emits pre-flash for metering purpose.

Hacking Flash, III

Where are the details?

I will be publishing details of the hacks in the coming days. Stay tuned (if you are interested).

Posted in: DIY Photography on February 3rd, 2010. Trackback URI
Keywords: , , , ,

Related Posts


« Previous story
Next story »