I've been shooting these type of macro floral photos for several years. Since the focus is so shallow I've always tried to shoot them indoors under more controlled conditions. Lately, I've been trying them outdoors with some success when it's not windy. This is a passion flower in our backyard. 1/60 sec at f/2 with extension tubes, ISO400.
Several years ago Larry Patrick and I experimented with portrait lighting with colored gells. It was one of those things that you see other photographers do and think you should try. You think it would be easy but as Larry and I found out at that day -- not so much. We made some critical errors in our efforts that day -- shooting too shallow depth of field, not really focusing on how the colors would mix, and most importantly the intensity of the gells coupled with the overall ambient exposure. So, needless to say those images never saw the light of day. But I always had it in my mind to try it again, and when a photo shoot last weekend got moved from outdoors to indoors I thought it would be a good time to revisit this technique. The image above of April was taken using turquoise and orange gells, really knocking down the ambient exposure with shutter speed, and selectively lighting with snoots on the gelled speedlights. And one more important thing I learned: even the slightest change in position and direction of the light makes a huge difference. 1/125 sec at f/7.1, ISO200, 85mm.
I've been experimenting with in-camera double and triple exposure lately. Pretty amazing technology, where you can tell the camera to overlay two or three consecutive images together all the while allowing for the exposure gain. Amazingly the combined composite turns out remarkably well exposed. The above was some fall flowers. After so many years of Photoshop and its infinite possibilities, it's different and challenging to do this so randomly in camera.