[MF3D.FORUM:632] Re: Thanks Paul

["Bill Glickman" <bglick@xxxxxxxx>]

Brian

      I was very familiar with the test results of C Perez.  C Perez
purposely did not test the LF lenses at anything smaller than f11.  Most
were tested at f16, f22, and f32.  The very best LF lenses of today can
resolve about 70 lpmm, such as the super symar XL's.   However most still
average in the 60's, while slightly older lenses perform in the 50's lpmm.
New MF glass has resolved up to 130 lpmm while average MF modern glass still
averages about a 100 lpmm.  However, this is a mute point when it comes to
MF stereo since we all agree the resolving powers of all these lenses are
more than what is required in MF stereo.

      My only point was, at wider apertures where it sometimes would be
desirable to shoot MF stereo to prevent blur from wind or shooting moving
subjects, etc.... With MF, you have that option.. while LF lenses are very
very poor at the wider apt., say f5.6.   Even both my Super Symar XL's
performed poorly when shot at 5.6 and 8.  It becomes noticeable through a 4x
loupe.

 I hope I did not offend any LF lovers out there, I own 10 new LF lenses, so
I am a big fan of LF.  But I sure have a lot of slightly blurred shots in
8x10.


Regards
Bill G



 ----- Original Message -----
From: "Brian Reynolds" <reynolds@xxxxxxxxx>
To: "Medium Format 3D Photography" <MF3D.Forum@xxxxxxxxxxxxx>
Sent: Thursday, June 01, 2000 4:33 AM
Subject: [MF3D.FORUM:629] Re: Thanks Paul


> Bill Glickman wrote:
> > But what I was mainly referring to was a deciding on a versatile
> > lens, one that can shoot at 5.6 if you are shooting waves crashing
> > on rocks...(achieve stop motion) in which case many LF lenses would
> > produce very poor results.... and this is due to their very poor MTF
> > curves at these wide apt.  So bad it would be noticeable in the
> > viewer when shot wide open..  MF glass, has excellent sharpness over
> > almost the entire f stop range, usually tailing downwards at the
> > smallest openings.  But in still situations, I totally agree, stop
> > all the way down, you are not enlarging enough to allow diffraction
> > to rear its ugly head!
> >
>
> You shouldn't be so quick to judge LF lenses inferior.  A little while
> ago Kerry Thalmann, Mike McDonald, and Chris Perez did a series of
> lens tests on MF and LF lenses.  Their intent was to cherry pick the
> best lenses available to them.  In the course of their testing some
> people sent them additional lenses to test.  You can see the tests and
> conclusions at <URL:http://www.hevanet.com/cperez/>.
>
> Basically modern LF lenses perform just as well as modern MF lenses,
> and 50 year old LF lenses (Kodak Ektars) are just about as good as
> modern ones.  They also showed that you do not have to stop all the
> way down (even with 8x10).  Of course LF has swings and tilts to
> maximize DOF.  They did find a correlation between price and
> performance.
>
> --
> Brian Reynolds                  | "Dee Dee!  Don't touch that button!"
> reynolds@xxxxxxxxx              | "Oooh!"
> http://www.panix.com/~reynolds  |    -- Dexter and Dee Dee
> NAR# 54438                      |       "Dexter's Laboratory"
>