Nikkor 105mm: f/2.5 vs. f/1.8
Rene van Oostrum
I'm in the market for a 105 mm Nikkor, and would like some advice
regarding the f/2.5 vs. the f/1.8 version. The f/1.8 has the obvious
one stop extra advantage, and photodo rates it higher than the
f/2.5. However, the photodo ratings are based solely on MTF, which is
a useful measure, but doesn't tell the whole story.
The f/2.5 is often referred to as "a great portrait lens" or even
"legendaric", and David Ruether rates it higher than the f/1.8.
So I'm wondering: what would be the advantages of the f/2.5 over the
f/1.8 (except the lower cost of the f/2.5). I'm especially interested
in the opinion of people that used both lenses.
Thanks,
Rene
Fred Whitlock
another one or has significantly more elements it's a pretty
good bet that it will have some compromises in terms of
performance. The price one pays for speed is to lose some
edge sharpness or gain some distortion or lose some contrast
or something. It's not always the case but almost always.
It's almost impossible that the f1.8 can outperform the
f2.5, even at smaller apertures. I'm not suggesting it
doesn't but I'd be surprised if it did. It is illogical
that it would. It is almost axiomatic that slower and
simpler is better for basic performance parameters (except
with zoom lenses for a lot of different reasons.) The 5
element f2.5 Nikkor 105 is and always has been an
exceptional lens to a large extent because of its
simplicity.
A friend of mine and I went shooting for fun one day last
year with antique cameras. He used a late 1930's vintage
Contax with a 50mm Zeiss Tessar lens. The Velvia chromes he
made that day were simply stunning. They were sharper and
crisper and contrastier than most chromes made with modern
day lenses. Why? The Tessar only has 4 elements and it
happens to be an exceptional design despite its age.
Plenty of modern view camera lenses are still made with the
Tessar design. Simplicity has a lot going for it.
I don't even know what MTF means but my impression is that
it isn't a very important criterion for judging lenses. I
say that mainly because I disagree with Photodo's
comparisons often for lenses that I've tested myself. Not
occasionally-often. I'm not suggesting their MTF figures
are inaccurate. I'm suggesting they may not matter and I'm
fairly certain they don't matter to me. The problem could
be the subject. Most test bench measurements are made using
flat targets. In the real world we photograph 3D subjects.
Some lenses are designed for flat field copy work and they
do much better than regular lenses when photographing flat
subjects. I'd bet they would win the MTF sweepstakes every
time. I don't have an optical test bench and don't test
lenses that way so I'm just guessing at this.
The f1.8 is one of the few Nikkors I haven't used personally
but I'm very familiar with David Reuther's test procedures
and I'd accept his opinion of a lens well before I'd accept
the "opinion" of Photodo. David makes exposures at each
aperture on fine grained black and white film of familiar
subjects (real 3D subjects, too, by the way) and then views
the negatives with a high maginification loupe. I believe
he told me he views them wet. That way he knows at which
aperture a lens will begin to provide corner to corner
sharpness and how distortion might vary with aperture. When
David says the f2.5 is sharper he means it has better edge
and corner sharpness than the other lens at apertures they
share in common or at least the wider two or three apertures
they share in common. I test lenses basically the same way
except I use subjects that are familiar to me (both flat and
3D), I do some mechanical things differently than David
does, and I use color transparency film because I'm also
interested in a lens's style of rendering color. I also
find that I get more consistent results from the E6 machine
processing. Contrast can vary quite a bit in black and
white developing just from the amount and frequency of
agitation and I'm not as good at that as a machine is. I'm
kind of a contrast nut with lenses, too, as you may gather
from my defense of simple designs with fewer elements.
So David, come out of the woodwork and tell me something
about MTF. It seems to have taken the newsgroup by storm
and I don't even know what it stands for or why it matters.
Good shooting.
Fred
Maplewood Photography
http://www.maplewoodphoto.com
Rene van Oostrum wrote in message ...
Petri Kekkonen
: I don't even know what MTF means but my impression is that
: it isn't a very important criterion for judging lenses. I
: say that mainly because I disagree with Photodo's
: comparisons often for lenses that I've tested myself. Not
: occasionally-often. I'm not suggesting their MTF figures
: are inaccurate. I'm suggesting they may not matter and I'm
: So David, come out of the woodwork and tell me something
: about MTF. It seems to have taken the newsgroup by storm
: and I don't even know what it stands for or why it matters.
Why cannot you just read
http://www.photodo.com/templates/display.lasso?show=443
and stop telling everybody that you don't know what MTF is about.
- Petri
--
/ Petri.K...@oulu.fi - RockFord - http://spaceweb.oulu.fi/~petri/ \
| Space Physics Group, Dept of Phys. Sciences, Univ. of Oulu, Finland |
| PGP public key http://spaceweb.oulu.fi/~petri/pk.asc - ICQ# 8997422 |
\ "Passion Love Sex Money - Violence Religion Injustice Death" - PSB /
Capt. Ahab
You know, there is very little calling to insult one another in a NG -
especially one designed for our mutual benefit and assistance.
I appreciate Fred's comments. I really wish that my friends and fellow
photogs here would be a bit more tolerant.
Capt. Ahab
Petri Kekkonen wrote in message <7jqitq$a9k$1...@ousrvr3.oulu.fi>...
>Fred Whitlock (a...@cl-sys.com) wrote:
>: I don't even know what MTF means I'm not suggesting their MTF figures
>: are inaccurate. I'm suggesting they may not matter and I'm fairly
certain they don't matter to me>
NetSet
> So David, come out of the woodwork and tell me something
> about MTF. It seems to have taken the newsgroup by storm
> and I don't even know what it stands for or why it matters.
>
www.photodo.com/ under 'lenses' / 'read our explanations'
Also notice the list of articles in the left window, especially
"Resolution, contrast, MTF" by Lars Kjellberg which might
interest you!
Furthermore the article from Canon lens support: "Understanding
the MTF graph"(quote):
"MTF stands for Modular Transfer Function. It is one method of
evaluating lens performance based on the contrast ratio.
.....
Bear in mind that the MTF curves of a lens should only be
compared to those of a lens with an identical or similar focal
length."
/HE
Fred Whitlock
will no longer say that I don't know what it means. I
continue to believe that it's a poor, or at least
incomplete, method for rating a lens. I continue to
disagree with many of the comparisons that I read (from
others on this newsgroup) this group makes. I don't doubt
their (Photodo's) sincerity. I question how important these
measurements of test targets are in real photography with
real 3D photographic subjects photographed in vivid color.
I'd recommend to the readers of this newsgroup that choosing
a lens based on this one parameter is ill advised. I don't
question that lenses with "good" MTF can't be excellent
lenses but I can tell you from real practical experience
that some lenses with "worse" MTF are better lenses than
some with "good" MTF for making real photographs of real
subjects. I withdraw from the debate because I really don't
care enough to continue it. I truly believe this site
(Photodo) does more harm than good and I'll leave it at
that. The really good news is that it's difficult to buy a
bad lens in this day and age. The advent of computer
assisted design has made it easier for designers to make
effective designs-particularly zooms. If one decides to
choose a lens based on a photograph of a test target made on
an optical bench then that's OK with me. I promise not to
attack Photodo and what they do again. I trust that will
make you feel better, Petri. I'm outta here. Good
shooting.
Fred
Maplewood Photography
http://www.maplewoodphoto.com
Petri Kekkonen wrote in message
<7jqitq$a9k$1...@ousrvr3.oulu.fi>...
>Fred Whitlock (a...@cl-sys.com) wrote:
>: I don't even know what MTF means but my impression is
that
>: it isn't a very important criterion for judging lenses.
I
>: say that mainly because I disagree with Photodo's
>: comparisons often for lenses that I've tested myself.
Not
>: occasionally-often. I'm not suggesting their MTF figures
>: are inaccurate. I'm suggesting they may not matter and
I'm
>
>: So David, come out of the woodwork and tell me something
>: about MTF. It seems to have taken the newsgroup by storm
>: and I don't even know what it stands for or why it
matters.
>
Tom
wrote:
> ...snip...
>Furthermore the article from Canon lens support: "Understanding
>the MTF graph"(quote):
>
>"MTF stands for Modular Transfer Function. It is one method of
>evaluating lens performance based on the contrast ratio.
>.....
Thats: "Modulation Transfer Function".
Tom
Washington, DC
PS - it works extremely well to judge / design lenses for scientific
and engineering applications.
Gary Frost
but distilling it down to a one-number rating. (ie. 4.2 vs. 4.4)
Look closely at the data and MTF curves: these are both superb
lenses. Within their aperture ranges, I doubt you could tell one
is sharper than the other. Base your choice of these 2 on something
else like price, weight, speed. Forget about any difference in
sharpness performance. Photodo MTF data is a valuable recource if
you read it carefully.
Gary Frost
Jsnack
>regarding the f/2.5 vs. the f/1.8 version.
Take a look at the Nikon 100/2.8 E lens. It's about the same size as a 50mm
lens and just as sharp as the 105s. They sell used for around $75.00-$150.00.
Look for one with the chrome mounting ring.
Chuck Ross
<a...@cl-sys.com> wrote:
> So David, come out of the woodwork and tell me something
> about MTF. It seems to have taken the newsgroup by storm
> and I don't even know what it stands for or why it matters.
>
> Good shooting.
>
> Fred
> Maplewood Photography
> http://www.maplewoodphoto.com
The answer to this is easily available on Photodo's web site.
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Modulation Transfer Function
Put simply, MTF-measurements assess the contrast between black
and white lines of differing thickness or line frequency, and give an
objective measurement of a lensน performance.
The MTF gives us a measurement of how much contrast remains
between white and black lines after they have been projected through
a lens. How big was the difference, or contrast, in the original? What
percentage of the original contrast is left after projection? If the MTF
for a particular line frequency is 0.85, that means that 85% of the
original contrast remains after projection. This decrease in contrast
does not only affect white and black surfaces; the difference between
dark grey and light grey surfaces also decreases by the same percentage.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
The equipment is at the site of Victor Hasselblad, and is used to
evaluate each lens coming off that line. Photodo's MTF tests are all
done by the same operator since day 1.
x-no-archive: yes
Fred Whitlock
understanding of it. I think it may have more value in
comparing two of the identical lens for QC purposes than it
does comparing two diaparate lenses. Curious though, I've
always thought the lenses were made for Hasselblad by Zeiss
rather than being Zeiss lenses manufactured by Hasselblad.
I wouldn't have expected there to be a lens production line
at Hasselblad. Goes to show you how out of touch we Mamiya
users are, huh?
Fred
Maplewood Photography
http://www.maplewoodphoto.com
Chuck Ross wrote in message ...
Chuck Ross
<a...@cl-sys.com> wrote:
> Thanks. I finally read the site and have a basic
> understanding of it. I think it may have more value in
> comparing two of the identical lens for QC purposes than it
> does comparing two diaparate lenses. Curious though, I've
> always thought the lenses were made for Hasselblad by Zeiss
> rather than being Zeiss lenses manufactured by Hasselblad.
> I wouldn't have expected there to be a lens production line
> at Hasselblad. Goes to show you how out of touch we Mamiya
> users are, huh?
There probably isn't a lens production line at Hasselblad.
I believe Zeiss still makes Zeiss lenses. Hasselblad only
checks the lenses arriving from Zeiss, I suppose. Or maybe
they take the Zeiss lens elements and stick 'em in the
Hasselblad lens mounts.
Who knows...
x-no-archive: yes
PA van Walree
> simpler is better for basic performance parameters
I wonder in which physics book you found this axiom. On the
contrary, a perfect (i.e., diffraction-limited) fast lens
almost by definition has a higher resolution than a perfect
slow lens. Isn't resolution a prime basic performance parameter?
Of course, one may wonder to what degree photographic lenses are
perfect (they are not). In practice, sometimes the faster lens is
better, sometimes the slower has the edge, but differences are
generally very small. Still, it's hard to improve on the performance
of a good brands 50/1.4 or a 85/1.4 employed at f/4.
Walrus