EF 70-300mm Why is the lens hood so large?

[Ramsden]

Hello

I got a new 70-300 lens to go with my EOS 90d a couple of weeks ago. I'm just curious why it comes with such a large hood.

I'm sure there's a good reason - which I hope you guys will tell me. 

Also, following on from that question, will a tulip hood make a huge difference.

Thanks

Ramsden

[p4pictures]

Light rays coming from the side of the a lens can bounce off the lens elements and reduce the contrast in the image. A lens hood stops such light rays from the side from even reaching the glass and thus allows the lens to perform to its optimum. 

Changing to a different hood than the one designed for the lens can result in one of two effects, the lens hood may actually appear around the edge of the image - vignetting - and or the different lens hood is less effective at blocking the light from the side resulting in lower contrast and possibly lens flare appearing in images.

For some lenses, the petal shaped hoods are suitable since the lens angle of view may necessitate a shorter side length to avoid vignetting. 

[Ramsden]

Thanks Brian

That makes perfect sense. I was just curious, because it was so different to my other lenses. I’m perfectly happy with the few shots I’ve managed to take so far - being snow bound in the North of England.

Ramsden

[p4pictures]

Broken cloud and 5C over Oxfordshire at the moment 

[normadel]

The 70-300's hood is "so big" because it is a shield to block out stray light coming from angles outside the lens's angle of view. A hood that is short would be pointless on a telephoto lens.  Tulip hoods are for wide-angle lenses and are a compromise. They offer SOME shielding from the sides where it is not needed as much as the top (from the sun). Some tulips provide almost NO side shielding, because they'd get in the way of a very-wide angle lens.

[Ramsden]

Thankyou.

So I can assume this is normal for most zoom lenses?

Ramsden

[p4pictures]

The shape of the lens hood depends on the lens - that’s why there are different ones for different lenses. 

My 16-35mm lens has a petal shaped hood. My 100-400mm has a straight hood, both are zoom lenses. My 24mm has a petal shaped hood, my 85mm, 100mm and 135mm lenses all have straight hoods. 

[normadel]

For zoom lenses the hood length and shape has to be a compromise between what's effective at the short end and at the long end. In theory, you would best have a wide short hood to put on at the shorter focal lengths and a narrower, longer hood to put on for the longer focal lengths. Since this isn't very practical, we compromise.