I mentioned the Nikon 60mm 2.8 Micro-Nikkor macro lens in a previous post. I used it for this photograph of the centre of a helianthus Lemon Queen but mounted a Nikon SB50DX speedlight on the camera that has the advantage of a tilting head that points downward.
The advantage of this is the f number in this case f45 (although interestingly the lens is only marked at f32) can be held as high as possible for the best depth of field possible. A ring flash that mounts around the lens would be better still but costs a lot of money beyond my means anyway. The photo shows more detail by this method of lighting.