One of the reasons I bought my Sigma 18-50 f/2.8 Macro is because I love macro and the perspectives you can get with super close focusing. Unfortunately I didn't realize how badly the lens would block light when getting in super close. At most angles even a bounce flash couldn't compensate so I finally made a ring flash.
I basically traced out the profile of my camera with my 580ex II on top and my lens fully extended to get a feel for the dimensions and went to work on a small cardboard box. Making the thing itself wasn't hard but it had a serious problem with light loss where the light had to reflect down into the channel that leads to the ring. I sort of fixed this by cutting out the then flat front and making an angle to reflect the light down better.
Another problems is that the light isn't even.
Has anyone found a way to fix this? I think I'm going to try to make a nicer one eventually and was wondering if creating separate light channels could help deal with the problem. What I was thinking was, in the vertical light channel, split the paths of the light three ways and only allowing maybe a 1/4 to come in directly to the top like this
Don't know how much that would help at the bottom but at least the sides would probably be a little more even. Either way I don't imagine this thing is going to have much range. It's not super efficient but up close obviously it works and I think it could work for portraiture as well.
