In article <49ga7l$9vd@harbinger.cc.monash.edu.au>, johny@fangorn.cs.monash.edu.au says...
>Will the quality of the image be heavily affected
>if filter (such as Hoya 1B) is put onto ultra-wide
>lens (such as 18mm)?
--No. Actually, the wider the lens, the more tolerance there is for
--some optical imperfections in the filter used (as long as they won't --begin to image on the film - superwides can have enough DOF at smaller
--apertures to begin to image dirt, hairs, etc. on the filter as blobs
--on the film) - a filter that would soften slightly the image of a
--300mm tele would probably show no ractical degradation of the 18mm
--image. BTW, Hoya filters are excellent, and they have thinner rims --than some other brands - important with superwides to avoid vignette.
>The reason why I'm asking is that a filter has some
>thickness. As the angle-of-view goes wider, the
>angle of the light paths measured against the normal
>increases and the effect of refraction will be more
>significant at the outermost region.
--Seems reasonable, but good filters have little or no discernable --effect on image quality regardless of the focal-length.
--Hope this helps.