On my recent Texas trip we drove by several fields of very large sunflowers on the way to the Santa Clara Ranch in Starr County. We were late and could not stop but I made time the next morning. I made lots of different images; this was my favorite by far.
Canon 800mm f/5.6L IS lens with a 25mm tube on the lens and the 1.4X II TC behind it (for closer focusing but you need to focus manually). ISO 400 in early morning light. Evaluative metering +2/3 stop: 1/160 sec. at f/11.
Don't be shy; all comments welcome.