Simple question – I’ve often wondered, when I see people using their cameras with the lens hood in the reversed (storage) position, why they bother leaving it on the lens…
I mean…more often than not they prevent you getting to the ‘zoom’ ring, and hoods are meant to SHADE the front element, to reduce flair etc.
These two are both for 77mm diameter lenses – the 70-200 f/2.8 and the 100-400 f/4.5 – 5.6 – the one to the right is just slightly deeper (logical when you consider the range of the zoom it’s usually mounted on) I dare say you could actually use either one for both lenses – the point of this is to prevent ‘stray’ light hitting the front element and creating flair by bouncing around inside the lens.
Another oft forgotten use for a lens hood is to provide a physical protection to the front of the lens – you’re wandering around, concentrating on not falling off a cliff, and the end of your lens hits a tree/rock/person…much better that an easily replaceable plastic hood gets damaged rather than an expensive lens element/barrel, or worse.
I do alot of my work in an environment lit by powerful stage lights – for me, a lens hood is vital – you may not even notice the effect it has, until you don’t use one and wonder why your images are sometimes a bit soft…
And did I ever mention a protective filter?