Recently when watching TV I realised that professional photographers often have a lens hood at the front of their lens. I don't own a lens hood yet, so I would like to know: - Is a lens hood good in general or only when you have sunlight/light from a side angel (that you want to avoid)? - Is it a "secret trick" of pro photographers to have the lens hood attached always or is that just a stupid idea of mine? - Are there any benefits/disadvantages of a lens hood? Thanks!