"MikeWhy"

Hi. I'm brand new to LF, and just bought my first camera and lens. I have a
question about the lens, a Schneider Angulon 90mm f/6.8. I know it's old;
the serial number is is mid 5 million, making it a two years my senior. The
trouble is, I can't seem to find any information about it on the web. What I
did find conflicted with everything else. I'm looking for just the angle of
coverage and coverage at infinity focus. It was mere curiosity before; now
that I have it in my hands, I'm concerned. I have loupes with more glass
than this lens has; it's not at all what I was expecting. Is this reasonable
for a 4x5 wide angle lens? Will I get reasonable coverage and movement on
4x5? The camera hasn't arrived yet, so I'll have to wait a few more days to
find out. In the meantime, you can help drive me crazy with more rumors and
suppositions. What can you tell me about this lens I bought?

Thanks.
Mike.

You're running into the gray area with some older lenses. They may illuminate
a large area before cutting off. But no standard exists to define the point
were performance drops enough to be unusable and a cutoff marked. In fact the
unable/unusable point could vary depending on the image. So you may find
different figures quoted by different sources. I often wonder how they defined
this usable circle to the nearest mm. I believe that most modern lenses are
mechanically cutoff at a point the maker believes is the usable limit. Again
there is no standard between manufacturers to define this point. So when
comparing lenses you really have to look beyond just the claimed circle since
no one keeps makers from expanding it for marketing purposes.
Chuck