Re: [KOML] Series filters AGAIN!

[Mel Brown <melbrown@eatel.net>]

Clive Warren wrote:

> At 5:04 pm -0500 27/11/97, James W. (Jim) Simmons wrote:
>
> >you need a series adapter let me know.  Once you start using series filters
> >you will know why the pro's of old (30-40 years ago, and before) used them.
> >Remember that was what your Koni lenses were designed to be used with!!
>
> Hang on a minute, why did pros of old use series filters then, other than
> the fact that they were for particular lenses which were highly regarded
> having that thread rate, and may have been of higher quality?  If it was
> because the filter glass was of higher quality than contemporary non-series
> mount,  then for us today the more easily obtainable non-series mount
> filters with modern coatings and glass will be superior and cheaper.

[chomp]

> ...For the
> Rapid-omega it is probably easier to use a Cokin or similar sqaure filter
> given the hassle in trying to work out relative rotations of a glass
> screw-in polariser.  Anyone have experiences that they would like to share?
>
> All the best,
>
>               Clive   http://clive.bel-epa.com

Clive, I'm not sure what Jim has in mind, but the only reason I remember for
using series filters was that, in the 1950s, some lenses had no threads for a
screw-in filter. Thus, it was necessary to use a series filter with a slip-on
adapter. Also then, before the introduction of zooms and large aperture
wide-angles, most lenses for a given film format were roughly the same diameter
at the front element. One would buy a single set of series filters to fit the
largest lens, then use appropriate adapters to use the same filters on the
smaller lenses. In no case was there a difference in quality between a series
filter and a fixed screw-in size.

A polarizer, whether screw-in or not, is mounted in a ring that rotates
independently of the screw-in threads. That's fine for an SLR, but is a concern
for RF and TLR cameras because it is not possible to see the effect of the
filter while it is mounted on the lens. One would have to remove the filter to
orient it as desired, note its rotational position, then screw it into the lens,
then re-establish the noted orientation. Clunky, but workable. The only other
time there is a problem with the orientation of a polarizer is on stupid lenses
with front elements that rotate to focus (not an issue with any Koni lens, of
course).

Regards,
Mel