Archived posting to the Leica Users Group, 1998/02/10

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Subject: Re: [Leica] 50mm Noctilux-M f1
From: "A S Jordan" <andrewsjordan@worldnet.att.net>
Date: Tue, 10 Feb 1998 23:40:38 -0500

- -----Original Message-----

>that the Noctilux is not a useful multi-purpose 50mm.)  Does anyone
>out there have this old report?
>Warrick

Warrick and  Noctilux fanatics:

You lucked out. I happen to have the Modern Photography test report on the
Noctilux lens(original published in March 1976 p. 114).In the photo Buying
Guide 1977 the report is reprinted. The following table is reproduced here
in an abbreviated form:

SERIAL NUMBER:2794632
RESOLUTION AT 1:47 magnification
f           center(lpmm)               corner(lpmm)
1            47                                    37
1.4         47                                    33
2            47                                    33
2.8         37                                    42
4            47                                    47
5.6         59                                    52
8            66                                    52
11          66                                    59


IMAGE CONTRAST AT 30 lpmm
f            center(%)                    corner(%)
1             44                                   16
1.4          44                                   16
2             46                                   16
2.8          54                                   18
4             62                                   40
5.6          59                                   52
8             60                                   60
11           55                                   54


It seems  that the resolution is fine; but at large apertures the contrast
is low. The Table also shows that at  smaller "normal" apertures the lens is
a good performer. Perhaps Erwin wants to comment about the validity of the
old Modern P. tests as well as the pictorial implications ol low contrast at
large apertures.
Flare was also pronounced between f1 and f2. Overall, I think the reviewer
preferred the older Noctilux f1.2 with 2 aspherical surfaces.
In the same volume, Modern P. provides a verbal evaluation per f stop of the
50mm f1.4 Summilux lens(excellent, very good, etc.). Clearly the Summilux is
superior to the Noctilux.
I also have a Xerox copy of a Modern P. review of the M4-2 from 1978 or 79.
Accompanying the evaluation of the camera, the magazine provided test report
on the 50/f2, 35/f1.4, 90/f2 and 135/f4 lenses. The measurement technique
was most likely analogus to the one employed in 1976 for the Noctilux. As a
basis of comparison I quote selected  values for the 50mm f2 Summicron:
RESOLUTION AT 1:50 magnification
f              center(lpmm)              corner(lpmm)
2               50                                  40
2.8            56                                  50
4               63                                  50
5.6            63                                  50
8               63                                  56
11             56                                  56

IMAGE CONTRAST at 30lpmm
f               center(%)                  corner(%)
2                42                                 32
2.8             50                                 40
4                56                                 50
5.6             58                                 54
8                58                                 52
11              54                                 48


I hope you will find this information helpful.


Regards, Andrew Jordan