On 6/3/2012 3:43 AM, Brian Swale wrote:
> Moose wrote
>> My limited experience is the closer the subject in focus and the farther
>> the background, the worse it gets. Limited experience because I was
>> shooting film and stopped wasting it on shots I knew I wouldn't like.
>>
>> Macro Bokeh Moose
> I am quite puzzled by this on several counts.
First, you have taken my comments out of context. The subject was the Zuiko
50/3.5 macro lens. My comments were directed
to that lens ALONE.
> 1) The background was already busy, and lousy bokeh could have been
> expected as a matter of course. Now that I think of this, I remember Wayne
> H asking us a few years ago to comment on the relative rendering of the
> bokeh of about 20 lenses - and in my opinion none of them had a chance
> because the background consisted of a lot of tortuously bent branches that
> were simply too close to the subject - one of his daughters if I remember
> correctly.
Here, I simply disagree, and there may be some definitional differences, as
well. Bokeh is not about the subject, but
about how the lens renders the out of focus parts of the subject. More
specifically, it is about what happens to small
highlights and to sharp edges between light and dark when they are out of focus.
There are differences between the sort of subject you describe and the other
extreme, say a portrait against a smooth,
featureless background. One may have opinions about such differences, likes and
dislikes, but they are not about bokeh.
In your example, a lens with poor bokeh would exaggerate the edges, making them
harder, and turn small bright spots into
larger areas with dark centers and bright, sharp edges (clear example below).
Light or dark lines against opposite
backgrounds tend to become multiple lines.
A lens with good bokeh would soften the edges. So, for example, a slim branch
against light sky would start to lose
definition at its edges, blending smoothly into the background, with some
remnant of center perhaps remaining as a
diffuse, darker line. Bright spots would also become diffuse, brightest at the
center and tapering off gently into
invisibility.
While not perfect, I hope this example helps to illustrate what I am saying.
<http://www.moosemystic.net/Gallery/tech/Bokeh/_MG_6431.htm>
So I think Wayne's subject as you describe it it would be a good test of bokeh,
as the test lenses and settings either
make the busyness stronger or softer.
> 2) The background was too close to the subject. Moose wrote " the closer
> the subject in focus and the farther the background, the worse it gets"..
Again, only about the 50/3.5. I would not claim that to be true of lenses in
general.
> My experience is opposite, as I recall. The closer the subject usually means
> the background is relatively far away ( better).
Reread what you have written. It is logically fallacious. Look at Jim's recent
orchid images. The subject is very close
to the background. Had he set them outside in his yard, the background across
the street would be far away. Background
distance has no necessary relationship to subject distance.
> The further away the background is ( especially when highly detailed and
> messy), the better. Better because every little bit of detail becomes
> relatively
> smaller, more out of focus, and therefore matters less.
This is not true of my experience with the 50/3.5. With that lens, my
experience is that the closer the subject and the
farther the background, the worse the bokeh. I have poor records of my old
images and nowhere near all of them have been
scanned, so I can't show an example, at least not without effort beyond what
I'm willing to expend on this subject.
There are few of them, as I quit using it that way as soon as I realized the
problem.
However, the 50/1.8s suffer much the same sort of bokeh problems as the 50/3.5,
although not quite as bad, so I will
illustrate with them.
Here, rolling the mouse up and down between the leftmost boxes, look at the
left edge. (The Zuiko and Zeiss are
essentially identical at f11.) At f11, you can already see the bright elements
starting to get edgy. At f8, although
blurrier overall, the bright elements have started to be darker in the center
and lighter at the edges. The brightest,
most complex one, just above center, has started to throw off separated halos.
<http://www.moosemystic.net/Gallery/tech/Lenses/50mm_lenses/50mmcomp.htm>
Wider open, and with background much further away the bokeh bokeh gets really
bad. In the upper image here, upper left,
large highlights have become almost circles of brightness, with hard edges. On
the upper right, smaller highlights,
brighter against darker background, have become full halos, bright circles with
fully dark centers. This is absolutely
not like the actual subject, and not unlike what mirror lenses do.
<http://www.moosemystic.net/Gallery/tech/Lenses/Misc/5018bokeh.htm>
Nor is what you suggest true of the two examples CH just posted. The
backgrounds in both of his images are close, and
the bokeh relatively good. In the first, there are a few large, hexagonal
highlights on the left with relatively even
illumination and moderately soft edges, moderately good bokeh, assisted by the
fact that they are not very bright. Bokeh
in the second is even better, indicating to me that the background is probably
even closer.
The only generalizations that I think can be fairly made about bokeh are that
for any particular lens (and focal length,
for zooms), it will differ with aperture and with subject/focal plane distance
and foreground/background distance.
Beyond that, it seems to be generally true that variations of the Double Gauss
design, which include virtually all
modern, fast lenses for 35 mm from about 40 to 80 mm, tend to suffer from poor
bokeh with relatively close subject and
distant background. In my limited testing, a 1950's Zeiss Jena 50/2.8 isn't
much different.
> My 2 cents.
Add mine, find a penny on the street, and you'll have a nickel. :-)
Holy Bokeh Moose
--
What if the Hokey Pokey *IS* what it's all about?
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