[Leica] Bokeh

[wildlightphoto at earthlink.net (wildlightphoto@earthlink.net)]

On Jan 23, 2009, at 11:10 PM, Geoff Hopkinson wrote:
>
> Some photos from two of my favourite Leica M lenses, The Summilux-M  
> 50mm f/1.4 ASPH. & the APO-Summicron-M  75mm f/2 ASPH.
> Note retention of shapes even in out of focus areas. See reproduction
> of highlights and rich tones in shadows. I typically shoot these  
> lenses from wide open to around f/4, like true believers should ;-). The 
> OoF  
> highlights of both are quite characteristic.
> The larger web sizes provide a better view.
> 50 wide open (film)
> http://www.pbase.com/hoppyman/image/90728291
>
> 50 f/5.6-ish (film)
> http://www.pbase.com/hoppyman/image/91239055
>
> 50 wide open (M8)
> http://gallery.leica-users.org/v/gh/a/usa/f/SM9.jpg.html
>
> 50 f/4-5.6-ish (M8)
> http://gallery.leica-users.org/v/gh/a/usa/d/SF11.jpg.html
>
>
> 75 at f/3.8 & f/4 (M8) <http://www.pbase.com/hoppyman/image/106035165>
> http://www.pbase.com/hoppyman/image/101824436
> http://gallery.leica-users.org/v/gh/a/f/IB1.jpg.html
>
> 75 f/2 (M8)
> http://www.pbase.com/hoppyman/image/101824440
> http://gallery.leica-users.org/v/gh/a/f/Borg.jpg.html
>

These are good examples of what can be expected from a well-corrected lens.  
It's typically not the buttery smooth bokeh of a lens with under-corrected 
spherical aberration, neither is it the harshness of an over-corrected lens. 
 The 50 wide open (on film) photo with OOF highlights illustrates the 
'neutral' bokeh:  

http://www.pbase.com/hoppyman/image/90728291

The distribution of light intensity is very uniform over the entire OOF 
point.  A 'smooth' bokeh lens will show higher intensity in the center of 
the disk and less toward the edges, a 'harsh' bokeh lens will show greater 
light intensity toward the edges and less in the center.

In my experience the 180mm APO-Elmarit-R and 280mm f/4 APO-Telyt-R also show 
this neutral disk with even illumination.  Sometimes I prefer the smoother 
look of the f/6.8 Telyts, especially when they turn water into liquid magic 
but the neutral bokeh of the APO lenses is VERY acceptable to me too.

Doug Herr
Birdman of Sacramento
http://www.wildlightphoto.com