First review Summicron-M ASPH

[Erwin Puts <imxputs@knoware.nl>]

Yesterday Leica officially announced the new Summicron-M ASPH (35mm). =
I have this lens since a few weeks on my M6 for review, but could not =
tell you about it. (embargo etc). A full report with all details will =
be available in a few weeks. But here is an extract of the report.
Leica is clearly practising the art of perfection with its third =
generation lenses for the M line. The new Sumicron ASPH vital =
measurements (current one in ()
Front lens diameter: 42 mm (42mm)
Lenght from bayonet flange: 34,5mm (26mm) 
Largest diameter:53mm (52mm)
Weight black/chrome:255 gram/340gr (160/250gr). 
Lenses/groups: 7(5) one aspherical : 7 (5).
The new lens has the now familiar concave outer surfaces of the front =
and rear elements as has the Summilux ASPH. The weight increase of =
100 gr can be attributed to heavier glass used in the construction. =
Particularly the rear most two lens elements are really fat. 
On test the new lens showed at full aperture  a high contrast image  =
with excellent rendition of very fine detail in the center (a circle =
with a diameter of =B1 12mm). Very high micro contrast crispened the =
edges of the very small details. Going outwards the image becomes =
softer at the edges gradually losing its very fine details when =
approaching the far out corners. Light fall off could be seen in the =
extreme corners, but is in practical shooting negligable. The current =
Summicron-M has the same overall contrast (Leica's prospect is not =
correct here), but loses out very slightly in microcontrast. The =
rendition of very fine detail is a bit softer and the gradation of =
small textures is slightly more washed out. The light fall off is a =
bit more pronounced, but still uninteresting. Most spectactular is =
the flatbess of field of the ASPH. Here we have a lens which at full =
aperture gives a completely flat image! The current Summicron is =
visibly more 'curved'. You need to see the comparative pictures to =
believe the stunning advantage. 
Fromf/ 2.8 to f/5,6 the ASPH reproduces the detail with increasing =
crispness and at f/5,6 reaches its optimum.Then the center qualities =
are extended into the far corners and we have a extremely high =
performer over the total negative area. The current Summicron folows =
exactly the same behaviour, but in the corners never reaches the =
qualities of the ASPH. In the center at f/5,6 the claim of Leica that =
the ASPH has a better resolution of very fine textural details than =
teh current one is borne out. However the German words ("deutlich =
uberlegen") when translated mean "clearly superior"  do the current =
one a disfavour. The difference is theer to be seen but not as =
clearly as this description suggests. From f/8,0 the quality drops a =
little as the edges of small details are softened. But for practical =
purposes both lenses can be used from 2.8 till 16.0 without =
reservation. 
In a nutshell: the new lens wins in the corners and has a better =
micro contrast which gives it the edge in the resolution  of =
extremely fine details which are also rendered more clearly and =
crisply. The flatness of field at full aperture is stunning. Flare =
suppression is excellent, but the ASPH is not perfect: in the  =
corners and sometimes (in very unfavourable circumstances well into =
the outer zones) you still detect traces of coma. 
From f/4,0 howver the differences are a little academic. They are =
certainly there, but if is important in practice?  
I also made an identical series of test pictures with Elite200. When =
using this film I was unable to detect the quality differences =
mentioned above. Only visible difference  was a slighty higher =
contrast, which was noted in direct comaprison. Viewed isolated the =
pictures looked the same. With the exception of the field flatness =
advantage of the ASP Hwhich was clearly noticable at full aperture.

So do you need to buy the new one if you have the current one? =
Ultimately the new one is the better lens, but depending on the kind =
of pictures you take you might see more or less of its quality =
advantage. As the quality is most visible at full aperture (flatness =
of field, excellent micro contrast and suppression of flare) the =
question depends on the percentage of pictures taken wide open and =
the quality you demand. Generally speaking the new lens scores with a =
very high sharpness of very fine details (and of course a excellent =
rendition of the   main object outlines). But the current lens is in =
these respects almost the equal. The new lens has visibly the edge =
but it is not a very marked one. 
More in a few weeks.
Erwin Puts