Sigma 62mm Macro Flash Adaptor for EM-140

Obviously different people will be buying this for different reasons... I bought it primarily for a Canon 24-105 lens on a 5D body (full-size sensor). I had expected this to cause a slight issue re vignetting at a wide angle (since the ring flash sits further in front of the lens) but I was very disappointed to find out it's an issue as long as 70mm focal length.

So... if you're using this on a full-frame sensor / film camera and want to use wide angle be very wary of the vignetting...