There is a lot of sense in using a card or other flat object to shade the lens, in that you can observe exactly where you need to cast the shadow by simply looking at the lens. With wide lenses you may need to exercise caution, but you can still do it and for a lot less money and weight than hoods, shades or compendiums. When shooting into the light, this may require something fixed to the front of the lens, although you'll have to be real careful to observe the gg with the lens at taking aperture to make certain you're not vignetting. In the motion picture industry, camera operators use a french flag to do this. This is a flat black piece of aluminum on the end of a thin gooseneck that attaches to the top of the camera. As far as hats go, I prefer to keep that on my head to hide my thin spot.