>news:3d3d01d9.1658641@newsstand.cit.cornell.edu...
>> On 22 Jul 2002 01:56:37 GMT, artkramr@aol.com (ArtKramr)
>> wrote:
>>
>> >>Subject: Re: How To Test My Lenses
>> >>From: "Alan Chan" wlachan@telus.net
>> >>Date: 7/21/02 6:28 PM Pacific Daylight Time
>> >>Message-id: <3dJ_8.18090$8D4.548263@news2.telusplanet.net>
>> >>
>> >>I have not followed this closely so I might miss something. What I have
>> >>noticed is that most people who so concerned about sharpness or
>resolution
>> >>of their lenses, often missed other characteristics of their lenses
>which
>> >>might affect the final output in practice. A sharper lens is not
>necessarily
>> >>a better lens imo.

>> >>> Yes - that is why I test. The results tell me if the lens
>> >>> is substandard or not (a simple comparison of the two short
>> >>> edges of subsequent frames, shot at the same wide stop and
>> >>> focus, of the same distant detailed subject, tells me if
>> >>> the lens is optically well-aligned, and if so, it is likely
>> >>> also to be about as sharp as another good sample of the
>> >>> same lens), and how it compares with other similar-FL
>> >>> lenses... In the process of simple alignment, wide vs.
>> >>> middle aperture sharpness, and corner vs. center sharpness
>> >>> testing on film, you can also get info on distortion, flare,
>> >>> etc. by using simple VF tests.
>> >>> (See: www.David-Ruether-Photography.com/slemn.html.)
>> >>> DR

>> >Your post brings to mind a series of landmark optical tests that Kodak
>ran some
>> >years back. They were known as the JND tests. JND stands for "Just
>Noticeable
>> >Difference". Kodak was out to determine how small a difference in results
>the
>> >human eye could detect. They made hundreds of prints and showed them to a
>wide
>> >variety of viewers from professional photographers to amateurs to casual
>> >snapshooters. The got the information they wanted, but something else
>emerged
>> >that was even more important than the original test goals. They found out
>that
>> >prints that were of higher contrast were perceived as being sharper even
>though
>> >they were actually less sharp. Of course, in lens design we balance
>contrast
>> >and resolution. If the greatest sharpness [resolution] is wanted, it is
>at the price of
>> >contrast and conversely. As a result Kodak designed the Commercial Ektars
>which
>> >optimized contrast. Nobody noticed that they weren't all that sharp.
>> >Arthur Kramer
>> >Visit my WW II B-26 website at:
>> >http://www.coastcomp.com/artkramer

>> I suspect that commonly, "sharpness" is taken as the
>> subjective combination of resolution and contrast...
>> In video this is a common problem - people have
>> trouble seeing that certain camcorders have (rather
>> obviously) lower resolution capability than some others
>> that have lower (and more suitable for general use)
>> image contrast. With lenses for stills, though, it is
>> preferable to maximize both contrast and resolution
>> (through good design), though ultimately there is a
>> need to trade off one for the other, and arrive at the
>> most ideal balance.
>> One example supporting what you report: I bought a
>> Rollei 35 with a 4-element Tessar-type lens that tests
>> not very high in resolution toward the image corners.
>> I sold it in favor of the model with a 5-element lens
>> that had obviously higher resolution in the corners.
>> My slides never had the "snap" of those shot with the
>> earlier camera, *even in the corners*. I sold the
>> "better" version and returned to using the "worse"...;-)
>>
>> David Ruether

On Tue, 23 Jul 2002 07:50:42 GMT, wrote:

>David and I have debated this issue several times years ago. I agree with
>Art that most people tend to prefer high contrast to high resolution. I
>think the reason is that high contrast simplifies the image slightly while
>high resolution makes it slightly more complex. I tend to like simplicity
>in graphic images. The differences can be subtle, of course. I'm one of
>the people who values high contrast while David seems to be on the
>resolution side. Yet we both use a lot of Nikkors which typically favor
>contrast over resolution in the design tradeoff. Glad to see you've dusted
>off the old 35mm cameras, David. I thought you had gone over completely to
>video. Just kidding.
>
>Fred
>Photo Forums
>http://www.photoforums.net

It is good to hear from you! (We used to correspond
rather often, back a-ways...) I'm not sure I quite
agree with some of the above, though...;-) As I pointed
out in my response to AK (with the Rollei 35 examples,
from about 20-25 years ago...), I prefer(ed) sharpness,
which is the combination of both resolution and contrast,
and when there is a distinct contest/tradeoff between
these (as with the two best Rollei 35 lenses, the
Tessar-type and the Sonnar-type [the Triotar was
despicable! ;-]), I also favor(ed) good contrast - but I
think a lens would have to show VERY, VERY high contrast
combined with VERY, VERY low resolution to actually
contribute much to the simplification of an image (and I
do like nicely-rendered textures...;-). Looking at your
fine, graphically-simplified images, I think it is choice
of lighting and framing that accomplishes the formal
simplification you seek, not the lack of lens
resolution...;-) As for the rest, I shoot video for fun
now, (and profit), with stills reserved for profit only,
but I keep up with matters of stills, have still a lot
to blab about in still-photography, and add to the reviews
of lenses (see the 17-35/18-35, and the revised 24-120
reviews, under "I babble" on my web page - and I update
the "SUBJECTIVE Lens Evaluations [Mostly Nikkors]"
article often), and I'm still changing my working methods
for shooting stills (an eye problem forced some of this,
darn!) and learning new things (always the hard way,
alas...;-), and writing again here (in very long, run-on
sentences) after being off for a while with video
interests...;-)