Re: [Leica] Re: Film vs Lens Resolutuon - facts wanted

[Jim Brick <jim@brick.org>]

Just curious... how many of you that are posting on this resolution thread,
have a UV permanently mounted on your lens? Could be oxymoronic you know...

;-)

Jim


At 08:44 AM 2/10/98 +1000, you wrote:
>
>> The recent add by Zeiss in PopPhoto claims a resolution of 300 l/mm for its
>> MacroPlanar 2,8/60. This claim I find on the high side. Leica lenses easily
>> handle 150 - 250 l/mm (areal resolution!!!!). But that is not the question.
>> Looked at the MTF curves the important figure is the contrast transfer at
>> 80 l/mm. Most lenses have really trouble getting this relatively low value
>> on the film with a good contrast.
>> So here you have it; on the face value most modern films will 'handle'
>> around 125 - 150 l/mm. Most lenses can on one count easily top these
>> figures and chalk up values of 150 and 300 l/m, depending on the
>> measurement method. This comparison gives the plus to lenses.
>> 
>> But lenses also are really in trouble to get 80 l/mm. In this comaprison
>> the film easily wins. If you go for high contrast transfer for both system
>> components (film and lens); the film can handle 40 to 80 l/mm and the lens
>> can handle 20 to 40 lines (or to be a bit tolerant 80 l/mm). In this
>> comparison both components are about equal. The best lenses just outperform
>> most films and the best films just outperform most lenses.
>> Are we lucky that with Leica lenses we can have the best of both worlds.
>


>Just to make things worse, I was reading an artical about the problems of
light
>scatter on/in the film.  Given the same "resolution", a smaller aperature
will
>give a better lpmm on the film.  Though your lens may give its best
performance
>at f4, f8 will probably give you better resolution on the film.
>
>Then again we can start on film flattening devices etc, etc.
>
>The lpmm of film is, I belive, performed using contact printing methods.
>
>    Duncan ( just adding annother level of complexity to the equation )
>