[Leica] 60/2.8 Macro question

["Anderson, Ferrel E" <AndersonF@ria.army.mil>]

I own both, and have used them extensively.  I have also tested them for
resolution with Kodak Technical Pan film and the old US National Bureau of
Standards testing targets.  I bought the 60 with the 1:1 extension ring in
mint condition for $250 (have to crow a little!), and didn't use it for a
while.  But when I did, I was amazed at the crispness and brilliance of the
slides I took of frost covered leaves at a distance of 10 feet.  I was also
impressed with pictures I took of old photographs at about 1:5 magnification
ratio.  The 60 resolved the printing pattern right into the corners, which I
could not achieve with the 65/3.5 black Elmar, the 90/2.8 Elmarit R, and the
100/4 Elmar  lenses.  Since those tests, I purchased the 100 APO, and have
found it to be an even better lens optically, but in normal conditions the
difference is difficult to detect.  

In resolution tests, the 100 APO is the best lens I have ever tested.  The
next best is the 60, and it is followed very closely by the 90/2.8.  The
resolution lines taken with the 100 are so sharp they seem to be etched on
the negative.  The maximum resolution the test could achieve at 26 focal
lengths is 80 lp/mm, but all of these lenses exceeded this figure handily
from the center to the far edge of the frame in both the tangential and
sagital orientations at their best apertures (f5.6-8).  The 60 and 100
lenses even resolved 80 lp/mm across the field at f2.8, and just got better
until they maxed out at f5.6-8 - and remember, these are macro lenses!  It
is interesting that at f11 and higher apertures the 60, 90 and 100 Elmar
lenses outperform the 100 APO.  If one is using f11 and smaller apertures
for macro work, these lenses will do a better job in terms of resolution.
This pattern was also shown in the test results that Popular Photography
published about two years ago.  As far as handling, the 60 is a delight to
use, mainly because focus is so easy to achieve.  It is much easier to focus
than the 50 Summicron R both for optical reasons and because of the steeper
focusing helical.  The 100 APO is easy to focus optically, but it takes a
lot of cranking, and, therefor, time to get to where you want to be.   The
older 60 takes E60 or serie VIII filters, whereas the newer version
(optically identical) takes E55 filters.  The 100 APO takes E60 filters.  A
nice feature of the 100 APO is that a tripod collar is available for it.
This is an advantage since the lens is heavy.   I consider the 60 to be more
versatile because of its angle of view (focal length), ease of focusing,
size, weight, and the use of accessories such as extension tubes, extenders,
and more readily available filters (E55).   On the other hand, the 100 APO
provides a greater distance to the subject which is an advantage for
lighting, perspective, and animal subjects. If I were restricted to one R
lens, the 60 would be my choice.

My feeling toward these two lenses if that they are unmatched in quality,
and that with them I can achieve the best possible optical performance.  The
only weak link is the guy or gal behind the camera.  They are superb lenses.