[Leica] Re: Se ? oritas on the Semana Santa procession (Mark Rabiner)

[rpalmier at depaul.edu (bob palmieri)]

On Apr 12, 2008, Mark Rabiner wrote:

> I know we're slightly kidding here but on the record I'd like to  
> state again
> and weigh in on the side of  I think the modern ASPH Leica glass  
> lacks in my
> opinion nothing.
> I find no reason not to use them. None.
> I find no brittleness. No lack of Bokeh. Nothing. Nothing negative.
> I have 16x20 fiber darkroom prints from many Leica modern ASPH glass.
> They don't look funny in any way that I can tell or anyone's had  
> the guts to
> tell me.

I should know better than to go here, but I guess that I don't.

I don't see anything "funny" in shots taken with this lens. Just like  
the apocryphal Marlboro, there's a Lot to Like in the ASPH 35.  One  
of these things is likely a great ability to separate the focal plane  
from the background.  But the way in which it accomplishes this is  
apparently not just by rendering this focal plane in a more acute way.

In fact, there's seems to be a fascinating difference between the 4th  
gen. spherical and the current version in something that looks like  
depth of field, although my consultant in optical science sez that  
it's actually more related to the ever-popular bokeh business.  When  
focused on a nearby object wide open, objects far distant from the  
focal plane are rendered more sharply in the spherical version than  
in the ASPH.  Here's one person's examples:

http://www.jimarnold.org/galleries/leica_35_test/

I used to think that this was all governed by the usual depth-of- 
field tables, but apparently this ain't the case.  Here's a statement  
from Bob Atkins:

Depth of field is also NOT directly related to background blur. Depth  
of field equations tell you over what range of distances objects will  
appear to be acceptably sharp (or at least not unacceptably unsharp).  
It tells you nothing about how much blur there will be of objects  
well outside the depth of field. That's governed by different  
physical parameters and determined using totally different equations.

According to my consultant, it's the wave equations (which take phase  
issues into account, among other things) that need to be considered  
in order to explain this seeming breach of all that we hold dear in  
the depth-of-field formulas.

Also, although I haven't done any rigorous tests for this, I hear  
tell there's enough difference in the distortion of the two that if  
you put straight lines really close to the edges of the frame (as I  
often do) there can be some slightly more visible bowing.  Here's a  
recent street snap, shot wide open with a 4th gen 35 that illustrates  
an instance where I'm really surprised at how well formed the store  
signs are across the street even though I'm focussed just a few feet  
in front of the camera.  Also, i put some stuff right up to the edges:

http://www.pbase.com/bobsworld/image/95559160

So, if you like the way your snaps look when made with a certain  
lens, trust your instincts.

Bob Palmieri