Controlled tests of 40mm f/1.4 Nokton Bokeh

[Amin Sabet]

I was just reading Gautham's excellent review of this lens (http://ziforums.com/reviews/showproduct.php/product/28) and felt it was time to collect a few of the bokeh tests together in one thread and dispel the myth that this lens has "harsh" bokeh.


Anupam Basu's comparison (http://decisivemomentum.blogspot.com/2008/04/leica-40mm-summicron-c-vs-cv-40mm.html)
Roland Ruehl's comparison (http://ferider.smugmug.com/gallery/2727734_MNe74#144981927_Y7jV9)
Jürgen Kook's comparison (http://www.pbase.com/juergenkook/bok_voigt_leica)

Comparison #1 shows harsher bokeh for the Summicron-C, a lens which some people say has similar bokeh to the last pre-asph 35mm Summicron, than for the Nokton at the same settings.
Comparison #2 shows harsher bokeh for the M-Rokkor and Summicron-C than for the Nokton at the same settings.
Comparison #3 shows similar bokeh for the Nokton and pre-asph Summilux wide open and at f/2, with the Nokton looking slightly better to my eye, especially at f/2.

I can only guess that the 40mm Nokton has a rep for harsh bokeh because it is manufactured by Cosina and relatively inexpensive. Anyone have a better explanation?

Addendum: I realize that there are other bokeh tests for this lens which conclude that this lens' OOF rendering is distracting, harsh, etc. However, I've come to believe that for a bokeh test of a given lens to be valid, it must involve comparisons with other lenses using the same subject.

[Brian]

Like most modern, fast lenses- the images show "donuts" in the out-of-focus areas. The 1950's S-Mount and LTM Nikkor-S.C. 5cm F1.4 is probably the "harshest" lens that I've used. But no one "knocks" it for its bokeh. The pre-war Sonnars are the smoothest super-speed lens that I've used. So much for the Nikkor being a "copy" of it. The Leitz Summarit is the "wildest" with astigmatism where the donuts become footballs. Yet, its one of my favorite lenses.

Some people like donuts.

[Amin Sabet]

I love the OOF rendering I'm seeing in your Sonnars, and it couldn't be more different than that of the Nikkor you mentioned. As you say, bokeh is subjective, and I've seen examples where the Nikkor harshness works to pleasing effect.

However, I think that if one were to do a blind taste test using any of the three examples above, the great majority of people would prefer the Nokton 40 over the Rokkor and the Summicron, and by a more narrow margin, over the pre-asph 35 lux as well. Yet the Nokton is often said to have "bad bokeh", whereas the other three are commonly praised for their OOF rendering.