8mm Forum: What is lens bloom?

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Posted by Alan Rik (Member # 73) on March 04, 2005, 07:56 PM:

Hi! Yes.. its Alan R. posting day! (sorry Kev.. just trying to catch up!)
What is lens bloom? I looked it up on the internet and couldn't find anything on it.
All that came up was Orlando Bloom. Who is he anyways? [Smile]

Posted by Kevin Faulkner (Member # 6) on March 05, 2005, 04:27 AM:

Len bloom is when something or other contaminates the coating on the lens. In some of the Elmo lenses you can see lens bloom on the inside elements. I was told a long time ago that this was caused by some adhesive that was used in the manufacture of these lenses breaking down and attacking the lens coatings on the inside. It makes the lens look as if its got a smokey coating on the inside when you view it with the projector lamp running.
Very often a strip down of the lens and a good clean will remove it but in very bad cases the only answer is to have the lens recoated.

Kev.

Posted by Jan Bister (Member # 332) on March 05, 2005, 09:00 AM:

Next time you Google around, try putting your search phrase in quotes, i.e. "lens bloom" instead of lens bloom [Wink]

as for Orlando Bloom, he's your typical young-stud Hollywood actor having appeared in recent features such as Pirates of the Caribbean and Troy... [Big Grin]

Back to the lens bloom... is that the one that would cause a kind of giant halo to appear around the rectangular projection image on the screen, with the halo somewhat lighting up the entire room?

Posted by Douglas Meltzer (Member # 28) on March 05, 2005, 02:38 PM:

Lens bloom makes your footage look as if it was shot with a diffusion filter. The highlights are spread out and the contrast is softened. In extreme cases, Jan's halo effect takes place, similar to looking at a bright window through a piece of gauze.

Doug

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