Curious on a LF lens quality

All true and pertinent, but a XENAR typically opens to f/3.5, compared to f/5.6
for a comparable Symmar, and is corrected for use at or near full aperture.
That's why thes lenses became known as "press lenses" because they could be
used handheld. Like the Planars and Xenotars used in medium format, the Xenars
were fast, contrasty lenses for 4x5 format. I have used all of the
aforementioned lenses extensively, and I admit I have greater trust in the
Symmars, and I usually shoot at f/22, but I have always been amazed by the
Xenar and Xenotar's performance at f/3.5 - f/4!



In article ,
says...


On Sep 6, 10:19*am, "LGLA" wrote:
Curious if anyone here uses any old Schneider Xenar 150mm on their 4x5? *Can
anyone
give a good impression of it's qualities? *I know it is a four element in
three group design
and related to the tessar design.

Large_Alex

The Tessar and the Xenar (as well as some other manufacturer's house
brands) are very similar. The performance of any used lens should be
evaluated by actual measurement since (for a used lens) it depends to
a degree on how the lens has been handled since manufacture. For
Schneider's lenses, prior to WWII, the quality control was a little
uneven, so if it is an early serial number, extra attention to an
actual test is a good idea. After the middle '50s, Schneider's QC
seems to be notably better. Even so, 1 test is worth many expert
opinions.

The primary reason that the Xenar is less widely used than it might be
is coverage, not sharpness. A good Tessar or Xenar can be very sharp
and contrasty. However, the coverage is significantly less than the
Symmar. The Schneider web site gives 62 degrees of cover at f:16 for
a Xenar (see:
http://www.schneideroptics.com/info/...at_lenses/xena
r/data/4,5-150mm.html
)

The corresponding claim for the Symmar of a similar age is 70
degrees. My experience with older Symmars is that some of them
'cover' (i.e., illuminate, with poorer quality) even more than that;
this property can be useful, sometimes. If memory serves faithfully,
I think Schneider at one time or another has actually claimed a little
more as the coverage of the older Symmars, but not recently.

Broadly, a good 150 mm. Symmar should cover an image circle of about
180 mm. in diameter and some might provide 60 line pairs/mm. over much
of that field if your demand for contrast is reasonable. If it
doesn't do better than 40 (especially in the center) either re-
consider your test method or throw it back.