Camera manufacturers are sneaky bastards: they will do anything to force you buying overpriced original equipment and accessories. That includes writing a piece of code in camera firmware which will make cameras incompatible to some 3rd party flash units, what I found out earlier this afternoon in a very annoying way: buying a flash which would not work on my Canon EOS 6D. It’s a Yongnuo YN468 speedlite flash that I bough second hand for around $50. The guy that sold it to me said he hardly ever used it. It sure does looks like new and when I tried it before buying, it worked just fine. The problem was I tried it in daylight on a parking lot and could not know that there will be issues in real use.
You can imagine my disappointment later that evening when I tried it indoors and although the bastard flashed happily, all my photographs remained completely underexposed. With some experimentation I realized it doesn’t want to synchronize with camera shutter unless I used extremely slow shutter speeds like 1/4 or 1/8 of a second. Even at 1/15, only about 50% images were lit by flash and the rest was either dark or had part of the frame obscured by shutter movement (image below).
I tried the flash on an ancient Canon EOS 300D that I hardly ever use these days and it worked perfectly: sync up to 1/200, TTL and even auto zoom worked flawlessly. No problems whatsoever. A quick Google search revealed I’m not the only one with a problem like that: it seems that Canon EOS 6D has a lot of issues with 3rd party flash units and that they are present because of firmware restrictions – Canon’s way of telling you to buy expensive Canon flash units. There is a newer version of this flash, the YongNuo YN-468 II that supposedly works on 6D, but I bought the first generation which doesn’t.
I almost reconciled with my bad luck and started surfing the web searching for an affordable flash that would work on my camera when I saw an image of hot-shoe contacts from some cheap basic flash unit and it dawned on me! This problem could be solved simply by forcing the camera to think the flash connected is not a Yongnuo YN468 but something even simpler. On a hot-shoe connector there are five contacts and only the upper one sends a signal when to trigger the flash. Others are there for advanced camera and flash communications like high speed sync, auto flash head zoom etc.
Covering the lower four contacts with a small cut-out piece of duct tape will cut off advanced camera and flash communication and the flash will fire without issues. You will lose TTL but shooting in manual mode will get you better results anyway. Auto zoom is also lost but that was not an issue for me since I mostly use prime lenses.
I’d like to end this post with a saying which is probably familiar to many of you: If it moves and it shouldn’t use duct tape. If it doesn’t move and it should, use WD-40. It seems this applies to Canon DSLR’s, but although using duct tape was successful in this case; please do not use WD-40 on your $1500 digital camera.