Category Archives: Photography

Yongnuo RF-602 Wireless Flash Transceivers and Receivers

A few thoughts and observations using the Yongnuo RF-602 wireless flash transceiver and receivers.

Max Sync Speed

Normally the Canon 5D has a max sync speed of 1/200 of a second, rather than the more usual 1/250, since it has a full frame sensor. When using the RF-602s, the max sync speed is reduced to 1/160 of a second. These numbers may vary depending on your equipment.

As a general rule I would recommend to test this before you go out shooting. Especially if you’re using a new camera, a new set of receivers or flashes.

Connecting the Receiver to the Flash Using a Cable

While the RF-602s works more or less flawlessly when the flash is connected using the hot-shoe on the receiver, using a cable (as shown in the image), may result in some strange behavior. In my case, for example, the receiver will no longer be able to wake up the flash from sleep. I’ve tested this on both my Canon Speedlite 580EX II with the same result.

This can be solved by disabling the sleep function on the flash unit.

Another thing I have observed on a few occasions is that the receivers stop working. I can be resolved by either turning of the flash unit and then turn it back on, or in some cases turn of the receiver and then turn it back on. Again, this seems to be a problem when using a cable instead of the hot-shoe mount.

Securing the Receiver on a Flash Stand

Based on what I’ve written above, you might wonder why I don’t simply use the hot-shoe on the receiver instead of the cable.

While connecting the flash unit to the receiver is no problem, connecting the receiver to a mount is a whole different story. Actually, the problem consists of securing the receiver to the mount. And the last thing you want is your expensive flash hitting the ground because your cheap receiver couldn’t hold on to the flash stand.

However, if you use a screw (like the one used when connection your camera to a tripod) instead of a hot-shoe mount, this shouldn’t be a problem. The important part is to make sure your flash is secure. Do not compromise.

Pentax AF-330FTZ and Hanimex 325AZ Trigger Voltage

Just a short post about camera flashes and trigger voltage.

Canon specifies a safe trigger voltage up to 6 volts using the hotshoe on their digital cameras. If it’s higher, it might damage the camera. So I have measured the trigger voltage on two older flashes I have lying around, since I didn’t get (m)any hits searching the interewebz.

Pentax AF-330FTZ has a trigger voltage of 3.14V
Hanimex 325AZ has a trigger voltage of 110V

So the Pentax AF-330FTZ should be safe. Hanimex 325 however, isn’t. What’s kind of scary is that I have used the Hanimex on several occasions on my 350D. Luckily no harm done (as far as I can tell).

Update: Found this web page explaining some more around this issue.

I take this to mean that all Canons DSLRs newer than the 350D, as well as all the professional models, can use flash with trigger voltages up to 250 volts in their hot-shoe. However, 6 volts is the safe limit for the D30, D60, 10D, 300D, and Canon’s digital compact cameras.