A cloth is more effective than a folding hood, but when I shoot 4x5", I often use only the folding hood and maybe a hat to provide a little extra shade, in part because I tend to choose 4x5" over a larger format in situations where I want to work more quickly and to be aware of my surroundings (i.e., not under the darkcloth in a crowded place). The folding hood is easier to use if you have a fresnel screen.