Re[2]: Dan / Would Perfect Lens have Bokeh?

[seungmin@luxmail.luxcom.com]

     Hi,
     
      Quite a while ago, I heard that Leica designed their lenses with some 
     aberations on purpose.  That is why we all have been talking about 
     bokeh.
     
     Regards,
     David 

______________________________ Reply Separator _________________________________
Subject: Re: Dan / Would Perfect Lens have Bokeh?
Author:  leica-users@mejac.palo-alto.ca.us at Internetmail
Date:    10/16/97 2:39 PM


At 02:59 PM 16-10-97 -0400, you wrote:
> Dan: Thats what I am asking - the perfect lens would have enough 
> aperture blades to be perfectly round and have no aberations at all. 
> The out of focus  points would then be all the same (round) and
> one manufacturers lens would be the same as all the others that
> produced this hypothetical perfect lens since you agree that this 
> "bokeh" is caused by the aberations in any particular lens and has 
> almost disappeared today from Leica's almost perfect asphericals;
> leaving Leica with a lens that takes almost perfect pictures but no 
> individual characteristics (Bokeh).  How many aperture blades does 
> it take to make a perfectly round circle and why is this desirable? 
>
> Marvin (just call me Alf) Moss
>***************************************************************************  
     
Firstly, I wouldn't assume that Leica's optics are aberation free; this is 
probably impossible to achieve.  Secondly, spherical aberation can be under 
or over-corrected, and the look of the "bokeh" depends on this fact.  In 
the article that appeared in Photo Techniques magazine that seemed to have 
started this talk about Bokeh (at least in North America), they referred to 
some Leica lenses as having good bokeh, and others that didn't.  Much of it 
is very subjective, and probably doesn't have much basis in sober 
scientific analysis.
     
Dan C.