Re: [Leica] The 3D Efect

["Martin V. Howard" <marho@ida.liu.se>]

John Gong wrote:
>
> I would rather believe that the 3d effect has to do with the contrast 
> characteristics of a given lens.  As I mentioned earlier, the lenses I 
> see this effect are my R series (35 summicron 1st gen, 85 summilux, 
> 35-70 ROM).  I also see them in some of my M lenses (35 summilux 
> aspherical, 75 summilux).
> 

Are you sure you're don't mean bokeh?  Most of thelenses you report
seeing this "3d-effect" with are exactly those that are often reported
as having very pleasing bokeh (35 summicron, 85 summilux, 75 summilux):
Out-of-focus highlights have slightly more intense cores and intensity
tapers towards the edge of the highlight disc.

According to an article in the May/June 1997 issue of Photo Techniques
(I think it was that issue), the result of this type of bokeh is that
the background retains some details, even when out-of-focus.  Thus, the
resulting image appears more three-dimensional than otherwise.

Other factors probably come into play too: I would be surprised if a
single factor alone was responsible for the "3d-effect":  If it was, 
we would expect to find it in more lenses, because fewer factors have
to combine to produce the effect (assuming random distribution).


M.

- -- 
Martin V. Howard, Application Systems Laboratory,     | 
Dept. of Comp. & Info. Sci., Linkoping University,    | Just "DOHH" it!
SE-581 83 Linkoping, Sweden.  Tel +46 13 282 421,     +----------------+
Fax +46 13 142 231; marho@ida.liu.se; www.ida.liu.se/~marho