When I initially shot this backlit sunflower, I recorded an acceptable exposure of the yellow petals because they are translucent. However, note the dark center of the flower in the first image. Since it isn’t translucent, it requires a much longer exposure time than the petals. The solution in this case was to place some fill light on the center of the flower with a reflector. I held up my gold reflector to bounce some sunlight back onto the dark center area. Presto! The difference is clear.

Here, the center of the flower is too dark.
80–200mm lens, f/8 for 1/200 sec.

Presto! A reflector does the trick.
80–200mm lens, f/8 for 1/200 sec.