-snip
>Are there any circumstances in which a MC filter would be either neutral or
>perhaps an improvement over a conventional uncoated filter with an SC lens?
>
>Lee, are you lurking? Others?
>
>Joel
>
Joel,
Coatings on lenses are there to reduce reflection from the_surface_of the
glass. A coating only works on the surface to which it is applied.
Multi-coating can be thought of as applying another anti-reflective coating
on top of an already coated lens in order to further reduce reflectance
from the surface. Similarly it only works on the surface to which it is
applied. It has no power to affect reflectance from surfaces to which it is
not applied. All glass, even coated ones, have some kind of reflection. If
they did not, a well coated lens would be well nigh invisible except for
its refractive and filtering properties. So, if you add an MC filter to the
front of the lens, you have added 2 more air-glass surfaces that will
have_some_reflectance. So Lee is correct, adding an MC filter will not
affect the reflection from any of the SC elements in your lens and it will
add its own minor reflectance to the sum of the whole. In addition, since
the filter is out on the end of the lens barrel its surface is even more
likely to be lit up by direct sunlight and flare introduced in the absence
of careful shading.
Hope this helps.
Winsor
Winsor Crosby
Long Beach, California
mailto:wincros@xxxxxxxxxxx
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