18th November 2003, 02:29 PM
Why a flower?
Why are those hoods shaped like a flower? Are they just round ones available? Why need to have them look like flowers?
18th November 2003, 03:03 PM
The flower ones are made in such a way to prevent fall off for the lens. You will probably realise that the flower ones usually accompany the wider lenses.
Originally Posted by ndroo
18th November 2003, 04:36 PM
err .. don't get u ... prevent fall off?
Originally Posted by coke21
18th November 2003, 04:52 PM
Found this interesting article on the above subject. Do searches on the Internet to get answers to everything (albeit sometimes not "zhun").
Article on lens hoods and why.
18th November 2003, 04:57 PM
*Pic not available, so just read from article.
Figure shows lens the occurrence of lens flare and the usefulness of a proper lens hood. There is a regular light ray that belongs to the photographed scene, this is the blue ray that arrives within the lens angle of view indicated by the brighter gray. This ray is normally refracted and contributes to the image formation. (Note however that I did not attempt genuine ray tracing, the light paths in figure 1 are merely illustrative.) There is also a slanting ray of sunlight that impinges upon the front element when a lens hood is absent. A small part of the light is reflected from the rear surface of this element (red arrow). A fraction of this light is reflected again from the front surface, directed to the film (dashed red line). This is flare.
© Paul van Walree
Last edited by PLRBEAR; 18th November 2003 at 10:27 PM.
18th November 2003, 05:01 PM
I believe fall-off is also another name for vignetting. Which is the unintended darkening of the image corners in a photographic image. Please correct me if i'm wrong. Thanks.
18th November 2003, 05:52 PM
Sorry, correction not for fall off but for vignetting. You can read more about it here
Originally Posted by PLRBEAR
Althought fall off and vignetting might have similarities, don't think they are caused by the same thing.
18th November 2003, 08:02 PM
thanks. the info from the link is great for a newbie like me cheers
18th November 2003, 09:27 PM