# Lens hood shapes. Whats the difference?



## uberben

I have been using rubber lens hoods for that past while now and I was wondering what the differences are between the rubber, petal and rectangular lens hoods are?


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## Hertz van Rental

The rubber hoods are circular so they don't have to go in a particular position. But you do have to make sure you get the right one for your lens.
The framing on a camera is not circular though, it is rectangular. A circular lens hood means that there are areas where the frame is a fair bit from the edge of the hood which could increase the risk of extraneous light causing flare.
The square hood is an attempt to remove this problem. The hood has the same format as the film and if the right hood for the lens is used the edge is just out of shot. This reduces the chance of flare to the minimum - but the hood has to be positioned exactly or you run the risk of vignetting.
The petal hoods are a half-way house. They are computer designed to be a compromise between a round and a square - and they are often designed for use on zoom lenses. The dips correspond to the film frame corners where vignetting is most likely to occur. Again, these hoods have to be positioned correctly in order to work properly.
Which one you use is up to you - although I wasn't given the option with my DSLR because it came with a petal. The important thing to remember is to always use some kind of hood and be aware of the problems off axis lights can cause.


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## Unimaxium

Hertz is right.
Here's a link that tells you pretty much all I think there is to possibly know about lens hoods, including the differences between different shapes.
http://www.vanwalree.com/optics/lenshood.html


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## uberben

Thanks for the info and the link. That answered all the questions i had.


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