Radio Trigger Sony Flashes !

Finally, I had found out how to trigger the all Sony flashes with radio signal !

I always wanted to find the way to trigger my Sony flashes with radio signal. Although all Sony flashes (except the "pop-up" HVL F20AM) are WL ready, but there are limitations to the existing build in WL system. With the non-standard hot-shoe on camera and on Sony flashes, it is impossible for any 3rd party radio trigger to work with A-mount system. Although there are hot shoe adaptors for flash and camera availble in the market, but having a much lower trigger voltage (as low as 1.5v) for the flashes made the 3rd party radio trigger couldn't work at all.

Not until one China manufacturer decides to make a Sony radio flash trigger system! Unfortunately, this product is meant for non-Sony flashes; it comes with a Sony mount transmitter, but with one or many ISO mount flash trigger(s). Hence, an hotshoe adaptor is needed for my flash to mount onto the trigger.

Introducing, the YongNuo CTR-301P Radio Trigger
for Sony (iISO mount on trigger)

I am thrilled, and bought a pair of it. But no luck for me b'cause the trigger couldn't trigger any of my Sony flashes (either the F36, F42 or F58). Even though I tried to PC sync'd it, still I have no luck. After consulting my friend, and my other best friend call Google, I finally found out that the receiver for this YongNuo CTR-301P required to be modded in order to work with Sony flashes. The theory behind is because of low trigger voltage of the Sony flashes, we need to by-pass the diode of the circuit of the trigger bla bla bla which I'm not quite understand.

Ok, how to mod ? I do not need soldering, what I need is a short cable and a small screw driver.

This is how the receiver looks like when open up. The cover is the part where the hotshoe is, and the cable connecting the hot-shoe to the circuit board can be easily dismantle because it's on "plug and play" type. "Un-plug" the cable for ease of working of course. The battery was removed from the board while modding the receiver.

What needed to do is to connect the negative battery terminal to the base plate of the flash hot-shoe.

A small length (about 1 inch) of cable will do. Trim out the both end part for about 1 cm length or so to expose the wire inside.

Unscrew the bottom plate of the hot-shoe. The plate will be loosen up. This is where the cable to be slotted in like the photo below:

Once the cable is slotted, put back the screws and tighten them. At the other end of the cable will be slotted onto the plat of the negative terminal of the battery. Upon closely examine the battery compartment, I found out that the cable is actually can be slotted onto the gap between the terminal plate and the battery holder. Once the battery is installed, the battery actually help to secure the cable on the plate itself !

The mod is done. Connect the red-black cable, close the cover, tighten up the screws, put in the battery, and I am ready to radio'd my flash !

I was happily mount my F42 on the trigger and test fired ! Nothing happened.
I mount my F58 on the trigger and test fired, it fired !
Tested on F42 again, the F42 seems doesn't want to fire. It doesn't like the trigger, I think....

Again, after some googling, finally I got my answer: the F42 needs to be sync with the camera body first before it can be radio trigger'd. The reason why need to do this is beyond my understanding. Hence, mounting my F42 onto the camera, half press the shutter button, take out the F42 without turning it off, mount it to the receiver, and walla, my flash fired under radio signal !

So, does this set-up syn with my camera at the highest syn speed ? Well, it syn at 1/250s !

At 1/200s.
(Exif intact.)

At 1/250s !
(Exif intact.)

Faster than that, I capture a curtain closing half way on my pictures. LOL

So, a question is raised : since our Sony cameras and flashes (except F20) are WL ready, why do I need to radio trigger'd ?

Simple : with radio signal, I do not need the line of sight for the off-camera flash to work.

However, there are some other pros about this radio-trigger, such as:
1) The flash can turn off the HSS mode !
2) The flash GN no longer depends on shutter speed. (Under HSS mode, GN of the flash reduce like hell.)
3) The delay between the signal fired till the flash fired reduce tremendously ! (There is a delay on Sony on-board WL system).
4) Flash can trigger at long distance. (Sony WL only at 6m or so.)
5) Flash can trigger under hot-sunny day. (Sony WL may not fired under sunny day).

Of course, I couldn't do high shutter speed shooting with this radio trigger. Under Sony's on-board WL system, the flash could even syn at 1/12,000s ! But the GN at that speed is super low. When on-earth I would use that speed under WL ??

And for sure I couldn't do TTL under radio trigger flash. Well, off camera shooting is all about manual setting, no ?

Anyway, the trigger fit very nice onto my camera because of its Sony mount. We no longer need another adaptor to mount the standard ISO hot-shoe trigger back then. It look nicer, and I like it very much ! :D

By the way, I found this Sony iISO mount Optical Trigger in the camera shop ! Couple with my radio trigger, it completes the whole radio trigger off camera system. I just need a radio trigger'd Sony flash as a "starter" to trigger the other optical slave'd Sony flashes ! Cool, right ? :)

Total cost on these set up (radio + 2 opticals) is about RM 220, a lot cheaper than a PW !! LOL

Can't wait to put this system into field test !

Update !
My flash merely fell from the trigger. No thanks to the SC-6 adaptor. How to prevent it? Read here.