[Leica] (no subject)

[freakscene at weirdness.com (Marty Deveney)]

>No argument from me on the two Leica lenses mentioned for extremely >good 
>out of focus rendition!  But others would say 'Oh the new designs 
>lack the smoothness or glow (or whatever) of the older lenses.

Those people are confused.  These are not bokeh.  Bokeh is blur, 
specifically the blur in out-of-focus areas of a photo.  It is not blur 
caused by subject or camera movement.  It's nothing else, although other 
things are aspects of it.  

Smoothness, glow, whatever describe either the rendition of the sharp part 
of the image or unquantifiable components.  Bokeh is just the out of focus 
area.

>For example, the last pre-asph Summicron 35 is often held to be a bo-ke 
>champion. It doesn't appeal to me at all compared to its asph. replacement. 
>I see a lot of that >smoothness as inability to resolve un-sharp detail, if 
>you like.

The differences are greater than that.  I think the version IV 35 Summicron 
definitely has the best bokeh of any lens I’ve used, but within a 
pretty narrow range of circumstances.  F4 or 5.6, focused between 1 and 4 
metres.  At f2, its bokeh is, to me, only average and overall, the 
Rodenstock Apo-Sironar view camera lenses, the Zeiss 110/2 for the 
Hasselblads and the 75 Summilux are much more consistent.

>What I call under-correction.

Here you stray into different territory.  This is the 'why'.  This we can 
measure.  From our discussions and looking at photos together, I think what 
you don’t like about the pre-asph look is that the contrast, 
particularly in its rendering of fine detail is lower than the asph.  When 
people talk about a resolution/contrast trade-off in lens design, they 
forget or don’t know that this occurs only when the lens’ chief 
limitation on performance is spherical aberration.  Once this aberration is 
corrected sufficiently to no longer become limiting, both contrast and 
resolution can be increased, as Leica did with the asph lenses, which, I am 
fairly sure, is what you and many other people like about them.  

These differences are more apparent at larger apertures.  At f5.6 and f8, of 
course, photos taken with the pre-asph and the asph show fewer differences.  
I really do think that Leica over-corrected the spherical aberrations with 
the early asph M lenses and designed them to render with too much contrast 
(for me!).  I think they think it too, because the rendition of the 50/1.4, 
the 75/2 and the 50/0.95 are quite different from all three 35s (two asphs 
and the aspherical) and the 90 (I haven’t used the 21 or 24 enough to 
comment).  You can measure this using sensitometric or output gamma curve 
analysis of a digital image of a photo of a test wedge (boring!).  

What goes along with better management of spherical aberration, however, is 
better bokeh (to most people, including me).

>So I was saying to the OP, what do you understand by bo-ke or bokeh or
>whatever you like to call it. Is it the way that OoF highlights are
>rendered? Or the transition from sharp to unsharp

These are aspects of bokeh, but these are not bokeh.  There is much 
confusion surrounding what is really a rather simple concept.  There is an 
amusing, interesting but unfortunately not very instructional thread about 
this on photo.net here: http://photo.net/classic-cameras-forum/00S2yV  which 
pretty much epitomises why I rarely look at photo.net.

I suspect what Doug was asking is 'what lenses show out of focus areas most 
pleasantly to you and why do you like that rendition?'  So what it looks 
like, how it renders highlights and how the in- to out-of-focus transition 
appears are all valid areas of discussion, but they are part of bokeh, but 
they are not bokeh.  Bokeh is just the blur...

>or some subjective Leica quality?

Absolutely not.  All lenses capable of creating out of focus areas using 
limited depth of field display bokeh.

And remember – all lenses (at least those available to us) are LOADED 
with aberrations of all kinds, whether we’re discussing the best Leica 
M or Zeiss camera lenses, the very best cine lenses (which put still camera 
lenses to shame anyway) or lenses for microscopes, binoculars or whatever 
else.  Most people don’t know how to look for them or what they are 
looking at when they see them.  To that extent, they don’t matter.  
But they are there.

Preferences, however, are preferences.  I still don't like my 35/1.4 asph 
very much, though I keep thinking that if I keep using it I'll like it 
better.

Let's all go take a picture, whether it has bokeh in it or not.

Marty

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