[Leica] (no subject)

[don.dory at gmail.com (Don Dory)]

Thank you for the intelligent overview of why some like one version of a
lens over another.  Or, use the tool that provides the look that you want.

On Tue, Jan 20, 2009 at 5:37 AM, Marty Deveney 
<freakscene@weirdness.com>wrote:

> >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&#8217;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&#8217;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&#8217;t know that this occurs only when the lens&#8217; 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&#8217;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 &#8211; all lenses (at least those available to us) are LOADED
> with aberrations of all kinds, whether we&#8217;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&#8217;t know how to look for them or what they are
> looking at when they see them.  To that extent, they don&#8217;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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-- 
Don
don.dory@gmail.com