[LargeFormat] Wide angle for XLF

[Michael Briggs]

The designs of the Grandagons and Super-Angulons (and also Nikkor-SWs and
Fuji-SW and -SWD) are quite similar.    These lenses are all designed to have
better light falloff than a standard lens design.   If with focal length X of
Brand Q of a lens listed above on format size Y with film Z, you find that you
need a center filter, then switching to Brand P from the list above is very
unlikely to change your need for a center filter.  These lenses are not
designed to need or not need a center filter: whether a photographer will want
a center filter depends on the format they are using the lens for, the type of
film, subject matter and their taste.

The super-wide lenses listed above have their characteristic appearance of very
wide outer elements (both front and back) compared to the width of the middle
elements because they are using a trick of tilting the enterance and exit
pupils.   You can see the effecting by looking at the front of one of these
lenses with the aperture stopped down about half way, and slowly turning the
lens from viewing it straight on to viewing it an angle.  The outside rim
of the lens will quickly become elliptical, but the aperture will remain closer
to a circle.   This effect theoretically reduces the light falloff to the third
power of cos theta, instead of the standard fourth.   In practice (based upon
the curves published by Rodenstock and Schneider), the improvement is not quite
as good.

The lenses mentioned in the first sentence have the improved falloff.  The old,
plain Angulons do not.  Nor the the new, high-technology Super-Symmar-XLs. 
In some cases, like yours of a 200 mm lens for 11x14, this is a reason to
select the Super-Angulon or Grandagon over the smaller Super-Symmar-XL.

--Michael


On 03-Mar-2003 Jim Hemenway wrote:
> 
> Having determined through some lens testing with paper negatives, that
> my Rodenstock 300mm and 210mm process lenses are not suitable for wide
> angle use on my 11x14, I'm now looking into the acquisition of a
> Schneider Super Angulon 210mm f:8.  
> 
> Do any of you know whether or not this lens needs a center filter, i.e.,
> was it designed to require one.
> 
> It appears that the Rodenstock 200mm Grandagon does require one and
> costs almost as much as the lens does - used.