Bokeh Is Not a Stable Characteristic of a Lens

I ran across a nice example yesterday of the same lens exhibiting both "good" and "bad" bokeh. I was looking through pictures taken with the old Olympus OM-Zuiko 50mm ƒ/1.8, a fine little lens (identical in design to an earlier generation of Leica Summicron, by the way) which is widely available for very little dosh. Take a look first at this lovely portrait by Konstantin Konduktorov, taken with the old lens adapted to a digital DSLR. Although there isn't "lots" of bokeh evident in the picture (I've always considered that a bit of a harebrained concept anyway, cf. "The Dog's Nose"), the blur is very smooth and gentle and provides just enough contrast with the sharper image of the woman's face.

Konstantin Konduktorov, detail. Soft blur and not too much
of it, with good coherence.

In general the old Oly "nifty fifty" renders bokeh quite nicely, among its other attributes. Fifty millimeter lenses are problematic in terms of their rendering away of the plane of best focus; not very many of them are always free of ugliness. While we're at it, note how smooth and subdued the in-focus image is, too, in this picture, despite being very sharp.

It's a nice old lens, and although prices are going up—I bought one for $10 in the '90s—you can have one for anywhere from $30 for a beater to $100 for one "new in box" when you can find it. And you can have it in single-coated or multi-coated flavors, too*—Japanese lens mavens prefer single-coated lenses for B&W film work. Note that this lens isn't good wide open. It cleans up nicely by ƒ/2.8, and is as sharp as it gets by ƒ/5.6, but I'd never shoot it wide open unless I really needed the speed.

This "new in box" sample of the Olympus OM-Zuiko 50mm ƒ/1.8
sold for $99 on February 16th

Now on to the negative example. Here's another shot by the same photographer with the same type of lens—probably the same exact lens unless Konstantin owns two samples. That ugly mess at the top, where the bright light comes through the trees, is very distracting. I might have cropped that out. 

Konstantin Konduktorov, detail. Ouch! That's not getting out of the way
like good blur should.

I should note also that you can "fix" bad bokeh in Photoshop to a certain extent, by reducing contrast and adding Gaussian blur, blending it into the picture with a layer mask. This would "step back" a little better, and draw less attention away from the subject.

Without correction past whatever the photographer applied, though, the two pictures are a nice demonstration that "bokeh" is not a stable characteristic of any lens. It can change with aperture, focus distance, whether the blurred object are in front of or behind the plane of focus, how much blurriness there is, and, especially, with what's being imaged. So we can't really talk about "the" bokeh of a particular lens, except generally.

Mike

*Here's how to tell. Older Zuikos had a letter code for the number of elements in the lens that preceded the word "Zuiko" (then and now Olympus's name for its lenses) with a letter and a period. For instance, "F," being the sixth letter in the alphabet, denoted six elements. When you find one of these 50mm ƒ/1.8's marked "F.Zuiko," that's a single-coated lens. Lenses marked "MC" are always multi-coated. Some have neither marking, but when you see the words "made in Japan" on the ring around the outermost element, that's also a multi-coated lens. (Those were later lenses after they stopped single-coating altogether, and the letters "MC" denoting multi-coating were deemed to be superfluous and were dropped.)

A "made in Japan" sample

Mike

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(To see all the comments, click on the "Comments" link below.)
Featured Comments from:

Michael Fewster [responding to another commenter, not the post —Ed.] wrote: "It always amuses me when people talk about 'natural bokeh.' There is no natural bokeh. It is an effect created by the lens and varies from lens to lens. Bokeh created 'artificially' by software in computational images as done in some camera phones or with post-processing software is every bit as natural.

"Of course, we might find some bokeh more pleasing than other bokeh but that is a question of aesthetics, not 'naturalness.' Computationally applied bokeh is not artificial. It is every bit as valid as that created by a lens."

Andy F (replying to Michael) wrote: "I don't think I've ever seen people talking about 'natural' bokeh, but I've certainly seen mention of neutral bokeh—that is, blur discs with neither overly hard nor overly soft edges.

"Incidentally, there is natural bokeh—your eyes are simple lenses, after all, so by focusing on something close up, things far away go blurry, and you can examine your eyes' natural bokeh. Mine isn't that pretty to be honest."

Mike J. replies: I think we can use any adjective we like to apply to bokeh, since they're just descriptive words. So you could call it "businesslike" or "prissy" or "craven" if you imagine those words will communicate your meaning. When trying to describe something, the words you choose are up to you.

Behind that, though, is our understanding of how the overall image communicates. Anything about bokeh (and everything else, really) relates to the effect it has on how the viewer understands and responds to the picture. As an extreme counterexample, take those attempts at pleasant portraiture that happen to catch two animals humping in the out-of-focus background. The humor comes from the dissonance between the putative subject and what the photograph accidentally shows. Also from the fact that the photographer failed miserably to put the viewer's attention or emphasis where he or she intended to put it.

You'll notice that several times in the post I did apply value judgements, though. I said that bad bokeh doesn't "get out of the way" and that it draws attention away from the subject, when it should "step back." This acknowledges that the child on the log is the subject of the second picture, and you want the rest of the picture—the "setting"—to set that off. With many good photographs of all kinds, many different elements of the picture contribute to the overall impression it makes. I've always been of the opinion that "bad" bokeh isn't a technical matter; it's just a question of how the out-of-d.o.f. areas contribute to or distract from the overall impression. The softest and most technically appealing bokeh in the world doesn't matter if the dog's nose isn't in focus—the picture is spoiled anyway. (That dog could be the brother of my Lulu, by the way. And any dog person would know instantly that that poor fellow is uncomfortable!)

Matt Kallio (partial comment): "Just as there are different qualities of bokeh, there are qualities of sharp too. The portrait is so sharp it takes me aback— yet it is pleasing in a way that my own over-sharpened images are not. Maybe Mike is reveling in his new eyesight and seeing everything that sharp, so he doesn't notice it. In normal life I never see anyone that sharply, particularly from the distance we're at in Mr. Konduktorov's portrait. Every hair...."

Peter Wright: "How I enjoyed this post! In a world seemingly obsessed with world stock market decline, virus outbreaks, climate threat, and of course, certifiably insane politicians of every stripe, it is so refreshing to come to a site on the Internet where the topic of discussion is the out-of-focus characteristics of a popular lens from last century! And I do mean that with total sincerity. Of course we need to consider the above problems (that we probably have little control over), but we need to leave room for that class of 'issues' that pose no threat, but seem to feed the soul, if we think about them."

Mike replies: That's TOP—incisive, insightful, irrelevant.  :-)

Stephen Scharf: "Andrew of the 'Danae & Andrew' YouTube channel did a really nice video back in October, 2018 of how viewers felt about different photographs shot wide open with fast lenses, or somewhat stopped down, say, ƒ/4 to ƒ/5.6. The link is below, but the bottom line is that viewers are much more concerned with the sharpness of the subject of the photograph than how out of focus the background is, and many viewers prefer to see some of the background behind the subject that helps tell the story, or provides a sense of place or context. Of note is his comments, 'what is in focus is always more important than what is not in focus,' and 'the average person cannot tell the difference between photos taken at difference of couple of aperture stops, even when looking for differences....' Link here (very insightful survey)."

Mike replies: His conclusions line up with my beliefs very well. Of course, it's mainly because I grew up in the era of lenses that performed more poorly wide open than today's lenses tend to do, but I've always recommended stopping down two or three stops for best optical quality.

Comments

[brian]

I chanced upon an interesting comparison of the rendering of out-of-focus areas produced by two recently-released 45mm lenses for the Sony system at relatively close focus. I'd be interested in understanding whatever appropriate terms (e.g., nisen, double-line, wiry, classic, or--as you wrote above--ugly) that could be used to describe the results from the new Samyang 45 that differ so greatly from those produced by the Sigma 45.

https://www.fredmiranda.com/forum/topic/1616217/1

[Christopher J. May]

I think the second picture is a bit of a torture test for bokeh. I've seen few lenses that deal with strongly backlit trees with aplomb. The best are the Minolta/Sony STF lenses.

Of course, that's also the kind of lighting where lenses like the Meyer Optik Trioplan would really show off their special "flavor" that has its own set of devotees. So I guess it's all relative.

[Christopher Mark Perez]

After many many years of chasing "pixies" around this topic of "bokeh", I've found I much prefer lenses that have neutral or under-corrected spherical aberrations behind the point of focus.

There are only two manufacturer's sources I've found for design decisions that take this subtle but very important effect into account. One is a white paper Zeiss published some years ago. The other is the "Thousand and One Nights" series published by Nikon. Because of their affordability (being retired and living on a fixed income, and all that) I've fallen in love with old manual focus Nikkors. Their out of focus rendition is consistently outstanding.

[marcin wuu]

The bokeh comparisons are somewhat similar to hifi gear reviews. For an audiophile sound is more important than music, for the bokeh lover image is more important than photography.

[Jim Metzger]

I can't get past the plastic rendering of skin texture on the models face. What else was "fixed" in this image? I think this makes it very hard to determine the bokeh exhibited by this lens in this image.

[Rob de Loe]

Before readers rush out and buy the OM 50/1.8, be aware that some of the 50/1.8s were notorious for oil leaking all over the aperture blades. You do want the "made in Japan" version that Mike shows.

The 50/1.4 is nice too (very soft and glowy wide open, but improves quickly). And Mike has previously written that the 50/2 is one of the best 50s one can buy. I agree having used it a lot!

OM serial number deciphering is a black art. I used the information at this site, which is copied from another site that no longer exists. I have found it to be quit reliable. https://www.fredmiranda.com/forum/topic/1121708/0&year=2012#10713211

[Michael Fewster]

It always amuses me when people talk about "natural bokeh." There is no natural bokeh. It is an effect created by the lens and varies from lens to lens. Bokeh created "artificially" by software in computational images as done in some camera phones or with pp software, is every bit as natural. Of course, we might find some bokeh more pleasing than other bokeh but that is a question of aesthetics, not "naturalness." Computationally applied bokeh is not artificial, it is every bit as valid as that created by a lens.

[Eamon Hickey]

Konstantin's shot with the backlit trees is very characteristic of every classic (read: ca. 70s, 80s, 90s) "nifty-fifty" SLR lens I've tried, all of which have been pretty similar double-gauss designs.

They give moderately yucky (that's the optical engineering term) bokeh when used wide open with lots of small, backlit detail in the background (foliage especially). Stopping down by even one stop improves the situation quite a bit, in my experience (which, of course, is not exhaustive, given that there are probably 50+ different varieties of that particular beast). In fairness, small, backlit detail in the background is hard for most lenses, I think.

[Dogman]

I guess I'm a connoisseur of ugly bokeh. I kinda like the OOF area in the second photo.

But really, I don't notice such things very often. Interesting photos are interesting to me, technically bad or not.

[Matt Kallio]

Agreeing with Jim Metzger. Just as there are different qualities of bokeh, there are qualities of sharp too. The portrait is so sharp it takes me aback -- yet it is pleasing in a way that my own over-sharpened images are not. Maybe Mike is reveling in his new eyesight and seeing everything that sharp, so he doesn't notice it. In normal life I never see anyone that sharply, particularly from the distance we're at in Mr.Konduktorov's portrait. Every hair...

[Chris]

Thanks for that information Mike. It seems that my two copies of the OM 50/1.8 are both single-coated lens. Good thing as I only use them with B&W film. :)

[Kenneth Tanaka]

What Eamon said. I know I have an old Canon FD 59mm f1.8 stuck on my old Canon TLb that exhibits the same crunchy "bokeh", at least on slide film. Never tried it on digital.

[Al C.]

Is inverse-mask + Gaussian blur acceptable, in good taste? I have always stopped myself short of local enhancements. Just seems a post step too far, although I suppose all adjustments are 'local.'

[Michael Fewster]

Response to Andy F's response to me.
I think many photographers do think of "Natural" and "artificial" bokeh. Compiled lens cameraphones that throw backgrounds out of focus are widely viewed as "artificial." About 10 years ago Alien Skins had a program "Bokeh" that enabled the user to add background bokeh and you could choose the "pattern" of bokeh you wanted based on the bokeh of some lenses well known for their bokeh. It was time consuming and not very good but I would think that the same could be done again today (and done much better) using computational techniques
The latest version of Photoshop claims to have improved its ability to create out of focus DOF.
My point is that such techniques are no more artificial, or unnatural, then what is added to an image by the lens design.
Which pattern of bokeh we prefer is another matter. Some patterns seem better with some subjects and other patterns with other subjects. I think the day is coming where PP we will look at our new image and then dial in the bokeh look we want for that image.

[Dragan Novakovic]

To my mind, the German photographer August Sander produced in much of his early 20th century work some most beautiful bokeh combined with extremely shallow depth of field. I wish I could find out what lens he used other than it being a Zeiss.

See, for example, his 'Confirmation candidate', 'Young farmers', 'Forester's child', 'Farmer' and 'Anton Räderscheidt' photos.

[Earl Dunbar]

I agree with Rob de Loë regarding the Zuiko 50/1.8 iterations, though I’ve never had the oil problem with my F.Zuiko - lucky I guess.

I am a big fan of the 50/1.4, of which there were 3 (4?) iterations, getting progressively sharper IIRC. My samples are from the 2nd generation, and I love how they render even though many don’t think any of the Zuiko 50/1.4 are that great.

PanF+ in one of Mike’s least favoruite developers LOL -

https://www.flickr.com/gp/edunbar/1a8zvb