Hi--

(Still buyied in the web project, but occasionally surfacing to answer e-mail...;-)

>You should not. My results are mostly verbatim translation of published MTF
>curves combined with practical experience. After all, lenses are supposed to
>take photographs and not just be judged by test charts! So, for instance, my
>observation that the performance of the AF-D Nikkor 105 f/2.8 deteriorates
>sharply beyond f/11 matches objective test results. Of course, MTF testing
>does *not* include the ill effects of chromatic aberration and neither do
>DOF calculation. I'm recently being aware of the sharpness decline that
>results from residual chromatic aberration in the out-of-focus zone, an
>optical defect that is increasingly more common amongst computer-optimised
>lenses. Neither is image-plane field curvature taken into consideration for
>MTF lens tests.

As a result of all this, I will be checking small-aperture performance
more carefully - and I have a 28mm f2 AI to run through the test in
comparison with other 28's...

>As you are well aware of, lenses also do differ in their
>performance according to the focused distance. Sometimes the performance
>difference is very great. I find a lot of wide-angle primes to be optimised
>for quite close distances. In fact, this holds for most Nikkors with
>floating elements. They may score very highly on shooting targets close up,
>less so at infinity.

I am amazed that this is so little recognized, and have been pushing the
concept on the 'net for a while, with little apparent recognition...
(chart-testing may place good lenses at considerable disadvantage, due
to the chosen test distance...). The MF 85 f2, 105's, and 135's are
notably poorer near minimum-focus than elsewhere...

>By the way, this also holds for the DAF-IF 200 f/4
>Micro-Nikkor, which truly is a phenomenal lens. Used for landscapes, the
>on-axis image of the 200 ED Micro is super sharp even wide open but the
>corners need f/11 to yield good sharpness.

I find this true of the 60, also (but it is a great lens for 2X with
the TC200/1, if you have enough front space).

>Beyond f/11, the quality declines
>rapidly and this is also evident up close for the 200. In fact, excepting
>the 105 UV Micro, all Micro-Nikkors should *not* be stopped down beyond f/11
>if optimal sharpness is sought. DOF considerations dictate f/16-f/22
>occasionally, but I prefer to know apriori the extent of image degradation
>at these apertures to allow me to decide whether enhanced DOF is worth the
>quality loss. Without being too categorical, I would recommend that f/11 be
>the limit for stopping down for *any 35mm lens* if professional image
>quality is to be achieved. By *professional quality* I mean images that can
>be printed as double-page spreads and still look sharp. When I go out using
>my middle and large-format cameras, I mentally adjust this limit to be f/22
>instead due to the relaxed tolerances of these larger film formats. 35mm is
>a small format and so much quality is potentially lost in the reproduction
>process afterwards that one should strive for the utmost quality of the
>image in the first hand.

I can't disagree with the f11-as-minimum-for-highest-quality concept, since
diffraction shows as the limiting factor beginning around f8 with many
lenses... I am just not ready to accept the f16-performance-varies-among
good-samples concept just yet, without finding it for myself... (for me,
it is like hearing an experienced car owner-lover saying, "BTW, most people
don't realize it, but the rear end of many cars shortens by about a foot
when the speed exceeds about 70mph..." - it is just TOO far from my
assumptions/experiences to accept easily (I am not into religion...;-).

>As I repeatedly have stated, the 20-35 f/2.8 Nikkor is a superb lens when
>used for its designated purpose, which is photojournalism. At f/5.6, the
>images produced by this lens are perfectly sharp across the frame with just
>a tinge of softness in the extreme corners. Contrast is very high to make
>the pictures "pop" (the correct wording?). I have shoot thousands of
>pictures with this lens and love it. Mounted on the F5, the perceived
>synergism between this lens and camera is simply stunning. Never have I felt
>this comfortable when taking on difficult assignments where time is short,
>ligh conditions unpredictable or terrible, and the results must be perfect.
>With this combo, I go on taking my pictures knowing they will come out
>perfect. However, taking the 20-35 for landscape work is a known disaster.
>Here the old 25-50 f/4 beckons to me like an old dog waiting to be walked.....

I sold my 25-50, due to the too-short zoom range... My guess is that
poor corners in the 20-35 would discourage me from using it (the 20mm
f2.8 is just plain fine by f5.6 with color film).

>>- I have noticed that the resolution of the 300mm f2.8 does not
>>improve appreciably when stopping down to mid stops, but the contrast
>>does ("sharpness" for me is a combination of resolution and contrast,
>>not just one or the other...),

>Again, we observe the same, but draw different conclusions. Of course, the
>image sharpness is influenced by *target* contrast. Shooting a high-contrast
>scene yield much higher image sharpness than that obtainable from a
>low-contrast scene. I'm acutely aware of this, because nature objects
>typically exhibit low contrast. However, as I stated previously, increase of
>image contrast by stopping down may not be sufficient to offset the loss of
>image resolution. This is very much the situation with the high-speed long
>Nikkors. After all, why haul the big 600 f/4 into the field to use it
>stopped down to f/8? Go for f/4 with that lens and make the most out of the
>shooting instead.

Hmmm, yes - though I STILL have a hard time believing that the overall
image quality would be *better* at f4, than, say, f5.6 (or even f8...).

>>- I would not trust Nikon's service for adequately checking anything - my
>>experience with them is that they can discern only gross alignment errors...

>Norway seems to be a better place for professional service facilities. The
>ultimate test is using a 20 mm wide-open at infinity to check whether image
>detail is truly in focus.

Yes, or a 16mm, or an 8mm... (though I find that the body AND lens tolerances
are off enough to make consistently correct infinity-focus rare - one just
learns to shim lenses, or mentally reset the focus marker...). Also, film
vs VF agreement is sometimes not precise - the unforgiveable error, since it
is hard to compensate for... (and Nikon US does not seem able to detect
this fault [or the lack of parallelism of the lens image with the film,
a common problem with short zooms], even when pointed out to them, with film examples.... - you are lucky, if your service is better).

>>- I find Velvia to be 40, relative to the vast majority of other slide film
>>speed ratings, but Nikon meters are often off the equivalent 1/3rd stop...

>Velvia is correctly rated at 50 ISO. The inherent elevated contrast of this
>film makes exposing it very tricky. 1/3 of a stop is on the edge of its
>tolerance. So, people calibrating their meters using the "sunny f/16" rule
>will in fact expose RVP at EI 64, which is too far away from the proper
>setting and is bound to yield unacceptable images under bright conditions
>(may still work with low-contrast objects, though).

Hmmm - I calibrate film speeds using the majority as reference, using two
reference light levels, and find most slide films correctly rated (by definition...), with only a few exceptions, one of which is Velvia. With
a grey subject, 40 seems to be correct, though Velvia is unusual in that it
does seem to vary with predomonant color, and I will go as high as 64 if
the subject is primarily bright green... (as with early summer landscapes
around here).

>>- I applaud the thoroughness of your set-up (but, ah, what distances do you
>>check at...?

>Near (1:10) , middle-range (1:100), and infinity. Macro lenses, also 1:2 and
>1:1.

>>- >(my name above isn't the way it is written in Norwegian and my ears cringe
>> >by the very thought of how the above is pronounced. However, given the
>> >American dominace in cyberspace, we minority people have no choice but
>> >following suit and try to use CyberEnglish)

>>Ah, yes, we do forget that we are blabbing in our native tongue, completely
>>unaware that most folks out there are having to struggle along wi' thet thar
>>ferrin lang-goo-ij...;-) ("with that there foreign language", if you needed
>>a translation...;-) Your English is superb, and considerably better than us
>>American's general grasp of our native language...;-)

>Thanks. Reading the rec.photo groups makes me wonder about the English I
>learnt in school....

Wha', it twern't *American*???! ;-)

>To end on a positive note, and with possible future use for your evaluation
>list of Nikkors:
>Which are the best of all Nikkors? At what aperture do they yield best
>results? The list below is subjective because lenses are targeted for
>different purposes and in fact are incommensurate, the ranking is relative
>because of the ties,
>
>1. UV[-Micro]-Nikkor 105 mm f/4.5. Possibly the sharpest lens ever made by
>Nikon. Optimum f/5.6. Made for UV and IR photography, its coating is not
>optimal for visible light so watch out for against-the-light flare. Performs
>without focus shift from UV to visible light.

I have never used this lens..., but your UV bee WAS interesting! ;-)

>1. 85 mm f/1.4 MF. Excellent wide open, peaks at f/2.8-f/4, still excellent
>by f/5.6. At f/4 using Panther (Lumiere) 50 it produces *tack sharp* images
>under 40X (!) magnification.

Hmmm - I have had "discussions" with people on the 'net when I held it
to be useable wide-open (best of 3-4 samples) - it is too low in contrast
wide-open for me for color use, though, with f5.6 or so yielding better
results for me... I do not find it peaking at 2.8-4, but beginning to perform
as I want there...

>1. Oscilloscope-Nikkor 55mm f/1.2. Strictly confined to the close-up range
>1:4.4 to 1:5.5, wonderful sharpness even wide open and superb at f/4 where
>all flare is gone. Note: Unsuitable for reverse mounting on a 200mm lens due
>to its limited chromatic correction. Not to be used with any TC.

Yes, I found this, also. The edges are poor reversed on the MF 105M, also,
but much of the frame is good.

>1. Ultra-Micro-Nikkor 28mm f/1.8. Used in reverse position, the sharpest
>macro lens I ever have tested. Used at 10X magnification it fills easily a
>6x9 frame to give stunning macro images. Best results from wide open to f/4.

The 35mm f4.5 is fine, too.

>2. DAF 200 mmm f/4 ED-IF Micro Nikkor. Top performance at f/5.6. Do not
>venture beyond f/11. Tremendous contrast and extreme colour saturation, in a
>class of its own. A pity its performance is so poor at f/22-f/32.

Not surprising, to us believers-in-diffraction-limiting...;-)
I have not tried this lens, but a friend owns one....

>2. 200 mm f/2 ED-IF Nikkor AIS. Extremely good wide open and even better at
>f/2.8, contrast increases up to f/5.6-f/8. Poor at small apertures.
>
>2. 300 mm f/2 ED-IF Nikkor AIS. A monstrous heavyweight capable of producing
>supersharp images even wide open. Do not stop down beyond f/8.
>
>3. 28 mm f/2 AI. Excellent even wide open, peak at f/4-f/5.6. Do not stop
>down beyond f/11. AIS version slightly different optical design, possibly
>matching the old lens' quality.

I have owned many samples of this, and we *must* be using different standards,
since I find it barely useable wide-open, decent by f4, peaking around f8,
and OK at f16 - in other words, what I would expect from the aperture-improvement/diffraction-limiting curve...

>3. 35 mm f/1.4 Nikkor AIS. Some flare wide open, at f/5.6 it is extremely
>sharp, in fact ranking among the sharpest of all Nikkors. (won't rate it
>higher because at other settings it isn't that magnificent).

Hmmm, these have been good, but not up to, say, the 35mm f2.8 latest PC
(really good wide-open, and FAR better in the corners), or even the MF
35mm f2 under some conditions).

>3. 50 mm f/1.8 Nikkor. Peaks at f/5.6, very good even wide open. The
>predecessor f/2 is quite similar, even slightly better wide open but
>contrast is somewhat lower.

Yes, I found this also.

>3. 55 mm f/3.5 Micro-Nikkor (preset and non-AI versions). Extremely sharp at
>f/5.6-f/8, optimised for close-ups, poor at infinity. Newer versions (AI)
>seemingly are optimised for infinity and perform less well up close. The 55
>f/2.8 is worse than the f/3.5's.

Hmmm... I found enough variation in the f3.5's to cover most of the above
(I have seen ones fine at infinity, some with bad field curvature). The
f2.8's have been VERY fine lenses at infinity and mid-distances, reducing
somewhat near minimum-focus - even wide-open...

>4. 24mm f/2.8 AI/AIS Nikkor. A very good allround performer, peaking at
>f/5.6-f/8.

I have had a bunch of these, and my conclusion is that I don't especially
like this lens. It is good in the center at all stops, but even stopping
down to f11 doesn't really bring the edges/corners above what I would
consider just OK - the 20mm f2.8 does much better toward the edge of coverage.

>4. Noct-Nikkor 58mm f/1.2. Good wide open and superb at f/2.8-f/4. Very
>strong curvature of field makes it unsuitable for shooting some objects.

The one I tried was probably defective - performance so-so until suddenly
at f5.6 it became superb.

>4. 105 mm f/4 Micro-Nikkor AI/AIS. Wonderful wide open and to approx. f/8,
>further stopping down gives poor images.
>
>4. 105 mm f/4 Bellows-Nikor. As the 105mm f/4 Micro.

The couple I tried were disappointing, at best - a surprise, and maybe
bad samples...

>4. 300 mm f/2.8 ED-IF Nikkor AIS. Very good wide open, still better one stop
>down. From there on the image quality drops fast. Handles very well on a
>tripod and is built like a tank.

Yes, though I found it peaked at f5.6-8 (surprise! Seems like almost all good lenses do that...;-)

>The 5th level would encompass the best Nikkor zoom lenses, which are:
>50-135 f/3.5, 25-50 f/4, 35-70 f/2.8D and 20-35/2.8, and possibly the newer
>80-200 f/2.8 ED's (not familar with those).

Same optics as older - SUPERB!

>I may have forgotten some good lenses because the Nikon family is so huge.

Ah, yes...
OK, my list (skipping the high-magnification macro lenses)...

1) 16mm f3.5 fisheye (good wide-open, snappy everywhere stopped down even
slightly), 20mm f2.8 (f5.6 at the widest, but very fine by then), 35mm
f2.8 PC (latest version, all stops not diffraction-limited [same comment
for all others, once optimum stop reached...;-]), 50mm f1.8's, 180mm f2.8 AF (just plain excellent).

2) 28mm f2.8 AIS (useable wide-open, excellent by f5.6), 28mm f4PC (stopped down), 55mm f2.8 (except for macro), 60mm f2.8 (except for near infinity),
85mm f2 and f1.4, 105mm f2.5/2.8 MF's (except near minimum-focus), 135mm f2 (NOT close up, but near infinity, it is VERY fine, even at f2, though with a touch of field curvature), 300mm f4 AF, 300mm f2.8 MF, 80-200mm f2.8 (very good wide-open, excellent one stop down), 75-150 (equals the best primes by about f5.6 - a REALLY sharp lens).

3) 35mm f2 (best sample of many, good even at f2), most other AIS primes,
and some zooms used optimally.

4) most of the rest of the AIS primes, and several zooms

6) several primarily AF zooms

8) the infamous 43-86mm

(The catagories are a bit "mushy"...;-)
Ah, well - back to the web page work...
David Ruether