I bought a simple and cheap pop-on diffuser for my Canon 750Ds built-in flash. It is attached by inserting a tiny lid into the camera hot shoe, bending it over the flash and securing it to the "brand plate" in the front of the camera. When I try to pop out the flash it tells me that "Flash is off or unsupported or an accessory is attached".

Is there any way I can get around that error?

  • Does that message also occur when you remove the diffuser? You certainly made sure the popup flash is not blocked by the diffuser. AFAIK those things are made completely from plastic, so I doubt that it has something to do with accidentally contacting the hotshoe contacts. But maybe there is a mechanical spring or something to detect the presence of a speedlight, that the diffuser activates? – smow Apr 14 '17 at 9:43
  • if I remove it the flash works just fine. It is also not blocked by the diffuser, as it is pointing away from the flash (you can only secure it in place, once the flash is up). It might very well be that the diffuser breaks the "spring circuit". In that case it would be an annoying move by Canon. – stebu92 Apr 14 '17 at 9:48

The hot shoe on your 750D is reporting the presence of the accessory attached to the hot shoe. Even though the accessory is not conductive, the pressure it places on the spring under the side rail on the right side of the hot shoe (as viewed from behind the camera) is depressing a switch under the hot shoe to let the camera know something is attached.

I wouldn't blame Canon, they've been doing it that way as long as the addition of popup flashes to SLRs. The blame should lie squarely on the shoulders of whoever designed your accessory. They should have known better. I have seen accessories intended for mounting on the hot shoe that only have one edge that fits below the outer rail on the opposite side of the shoe from the spring switch.

The only workaround I can think of that even might work is to pop the built-in flash up before attaching the accessory to the hot shoe.


I just solved the same issue with my Canon 80D. I found that the diffuser’s foot depresses a small bar on the right side of the hot shoe when it slides in. I cut away a small rectangular piece from the top right of the foot, leaving a little piece at the bottom so that it will still slide in, but now it doesn’t register with the hot shoe and the flash will work.


I had a similar problem w T6. All button sequences that should have raised the Built in flash did not work (Q button and selections, lighting button...). It reported that the flash is not available while other accessories are attached to the hot shoe.

Dirt, etc!

On the right side of the hot shoe rail, there is a leaf spring (helps hold accessories firmly in place, I Figure) which originates from the bottom and runs to the top. About 2/3s of the way forward (near the end of the leaf spring, on the floor of this shoe rail area, there is a TINY black button that gets depressed by that leaf spring when an accessory slides into the shoe. There is something (gray metal) on the vertical face of the most forward area of this hot shoe area. That is not it on the T6. The button is about the diameter of a paper clip. I used a very sharp knife to catch the side edge of the button and raise it up. There must have been a little accumulated dust. I “exercised the mechanism” popping it up and down. Thanks to all the folks that contributed and led me to this.

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