petal hoods for lenses

[reemas]

why are some hoods completely circular and some have grooves and cuts like that shape of petals?

is there a difference or benefit?

[drisley]

I believe that lenses that are longer generally have round hoods, while the wider angles have the petal hoods to prevent vignetting in the corners.

[kevin_c]

One of the main reasons for being able to use a 'petal' shaped hood is because the front element of the lens does not rotate, therefore a petal hood gives better protection from stray light from above or below as a round one could only be the depth of the shortest side of the petal type due to not knowing the orientation of the hood for any given shot.


Hope that makes sense!

[drisley]

Yup, that makes perfect sense.

[reemas]

so there is a specific way for the hood to go on? which way is that?

[jfrancho]

My Tamron hood will only go on the way it was intended. I am sure that is true for other petal type hoods.

[Huckaback Photo]

Hi Reemas
The Canon lenses that use petal shaped lens hoods are in fact a bayonet fitting (not threaded) so when fitted they should always lock on in the same possition.
That is until the lens has had some serious pro use when you realise the hood will go round and round cause the small stops are worn .
it always pays to look after the larger L series hoods as you will face a hefty bill if you need to replace them.
My small challenge to all,
If a 70 to 200 f2.8 costs £32
and 24to 70 f2.8 costs £45

How much do you recon for the 300mm f2.8 L is. replacement hood will cost ????

when you check this out, you may prefer to purchase another lense instead.

Cheers
Martin (Huckaback Photo)

My Gallery....http://www.pbase.com/huckaback_photo