:> -----Original Message----- :> From: owner-photoforum@xxxxxxxxxxxxxxxxxx [mailto:owner- :> photoforum@xxxxxxxxxxxxxxxxxx] On Behalf Of James Schenken :> Sent: 29 December 2007 15:19 :> To: List for Photo/Imaging Educators - Professionals - Students :> Subject: Re: Halo and blooming :> :> It seems that 'blooming' in a film camera can occur when the light :> intensity in an area is such that the adjacent areas get some of the :> photons that are not absorbed by the silver crystals. For this to :> happen in a digital camera, the individual pixel sensors would have :> to have at least semi-transparent walls that allowed reflected light :> to pass to adjacent sensors. To get significant 'blooming', the :> light intensity would have to be such that the adjacent sensors would :> pass it on, so to speak. :> :> Does anyone know if the side walls on image pixel sensors are at all :> transparent or not? :> :> For 'haloing' to occur in a digital camera, the software that does :> the interpolation to fill in the missing colors and adjusts the :> contrast could easily do this. You get the same effect by over :> sharpening in the image processing software. I'm not aware of a :> process that yields haloing in a film camera while the film is still :> in the camera. Help me if someone on the list does know how this might :> happen/ [Chris:] HALOES OCCUR IF THE LENS IS misted over. I think it occurs also if the developer is used up or the film is not agitated. Digital backs might do it if the photodiodes rob adjacent photodiodes of electricity thus making a dark ring round a bright area. Lens flare is another cause. This is where light shines on the lens surface. Blooming is (guessing) where a highlight is over exposed thus washing out detail. :> :> Cheers, :> James :> :> At 09:53 AM 12/29/2007 +0800, you wrote: :> >Eslon writes: :> > :> > :> >: I wonder why it seems to be seen as an aberration in this review of :> the :> >: Nikon D300: :> >: :> >: "The camera was loved for its "brilliant" image quality, its good :> colour :> >: balance, low noise and its LCD. However at times the D300 produced :> some :> >: minor haloing in high contrast areas." :> > :> > :> > :> >odd! they must have meant blooming I guess :> > :> >k :> :> James Schenken :>
