Bokeh: For and Against
bokeh railing

Towards the end of the 1990s, a new word entered the photographic lexicon. Originally spelled boke, it was soon changed to bokeh, to show that it wasn't supposed to rhyme with coke or soak. Now it is pronounced bow-kay or bow-kehhh, according to preference. Although the word is hopelessly over-used by some people, it is far from useless, as it replaces the somewhat cumbersome phrase that was in use before: the quality of the out-of-focus image. Long before the new word came into use, certain lenses had been prized for this: the original Voigtländer Apo-Lanthar was one. Others were generally agreed to have a rather nasty out-of-focus image: the doughnuts from a mirror lens, for example, or the 'wiry' way in which a Thambar may render fine lines.

Frosty Railing

This is right on the edge of our bokeh-tolerance. It's quite a nice shot, but it borders on gimmickry as a result of its ultra-shallow depth of field: Roger took it with a 135/2.8 Elmarit-M at full aperture on his Leica M8, where of course it is a 180mm equivalent. The out-of-focus blobs are dew on a spider web.

In Japanese the word has various meanings, including 'fuzzy', 'indistinct' and even 'senile', but the specifically photographic meaning was picked up by Mike Johnson in the 1990s and has been a source of controversy and even hysteria ever since. By great good fortune, as I started work on this module, Geoffrey Crawley came up with a wonderful definition for the English language: 'good bokeh (preservation of subject shape in out of focus planes)' [Amateur Photographer, 8 August 2009, page 74]

Musician

This was taken with a 50/1.2 Canon rangefinder lens from the early 1960s, adapted to an M8.2 with a Leica screw-to-bayonet adapter. On an M8 or M8.2, of course, the field of view of a 50mm is equivalent to a 67mm lens on full frame.

There is a charming roundness or three-dimensional effect in the picture, both in the focused zone (the girl's face and hands) and the out-of-focus area behind her. But how much of this (if anything) is bokeh?  From extensive experience of this lens, which we used over some 20 years, we are convinced that such merit as the picture has is a result of lighting and subject matter; the lens itself has taken good and bad pictures, according to where we pointed it, but apart from its softness wide open, it is hard to point to a general 'signature'.

girl with bass

 Of course some lenses are better than others, and suit some photographers better than others, but our own view is that bokeh is a quasi-mystical phenomenon: what suits one photographer won't necessarily suit another, and trying to pin it all on bokeh does not really advance the argument very much.

For some photographers, the problem soon arose that the bokeh tail soon started to wag the photographic dog. They became so obsessed with bokeh that they started composing pictures where the out-of-focus areas were more important than (or at least, as important as) the sharp areas. This sort of composition is possible, but it is also extremely difficult: not one in a hundred photographers can do it well. The bokeh addicts started buying extreme-speed lenses, and using them wide open, because that was the easiest way to get the most bokeh. This meant ultra-high shutter speeds, or neutral density filters, or both. It also meant a lot of very unsuccessful pictures.

atelier

Atelier du Buissonier

Several people have made very favourable comments about this picture, which Roger shot with his M8.2 and the 21mm f/1.4 Summilux when it first came out. Frankly, we don't like it. To us, it cries out for 'deep field' photography, because there is nothing in the picture deserving of more emphasis than anything else: the interest of such a subject, for us, lies in exploring the picture and finding things. This is what we mean about the tail wagging the dog: because people can use selective focus with a 21mm Summilux, they feel they have to.

 

Admittedly, some photographers seem to be a lot more sensitive to bokeh than others. Some don't notice at all; to some, it is the be-all and end-all; and in between, the vast majority of photographers are more or less aware of it. They may notice that one picture looks inexplicably better than they would expect, or inexplicably not as good. We have to admit that we are not outstandingly sensitive to bokeh, so that it has to be exceptionally nasty before we notice: we may therefore remark on unpleasant bokeh but we do not recall ever looking at a picture and saying, "What magnificent bokeh!" In other words, in our view, and in the view of many other photographers, that bokeh is best which is least obtrusive.

It's also fair to say that bokeh is frequently used as something of a catch-all to laud or deprecate several of those aspects of a lens that are not readily quantifiable. A kindred term, now substantially fallen into disuse (apparently it dates from the 19th century), is 'drawing'. As applied to lenses this is even more vague than bokeh. The closest it comes to precision is in the phrase 'rectilinear drawing' (as opposed to fish-eye or curvilinear drawing), but this is fairly specialized and more precise than most people have ever cared for.

Mostly, 'drawing' seems to have been a generalized term of praise: 'good drawing' seems to have included elements of bokeh, microcontrast and indeed 'plasticity'. Also in the 19th century, and well into the 20th, 'plastic' rendering was a popular term of praise. As far as we can work out, 'plastic' meant 'creating a three dimensional impression' but it seems also to have had aspects of bokeh in it.

claudia sewing

Claudia sewing a blouse

The 50/1.5 C-Sonnar which Roger used to take this picture is widely praised for its bokeh, which using Geoffrey's definition is very good indeed; it takes little imagination to read 'The Oxford English...' on the book beside her forehead. This is cropped out, pixel for pixel from the original M8.2 picture, in the sectional enlargement below.

 

oed oof

Besides, there are all kinds of other things, as well as the lens, that may contribute to what some people call bokeh. The subject matter. The light. The composition. The film, especially the choice between black and white and colour; or, of course, the choice of digital.

Bokeh is generally most obtrusive when one is deliberately using selective focus to try to isolate a subject from its background, but our own view is that unless bokeh is really unpleasant, it's good. In other words, there is no such thing as good bokeh: there is merely the absence of bad bokeh.

 

ellen and gun

Ellen with gun

Ellen is Claudia's sister, and as you might suspect from their different choices of recreation, they are rather different girls. Here, Roger used the Sonnar again (on the Leica M8.2, as before) to throw the background out of focus; otherwise, it might have been even more intrusive than it is. Inevitably, this threw the gun out of focus (an air pistol, by the way -- and she was already a pretty good shot, a month short of her tenth birthday) but this made its black bulk loom even more threateningly.

The point about differential focus is that for the most part, it's the differential focus that creates the impact, and not the out-of-focus area behind the subject. Few people, apart from bokeh-obsessed photographers, will pay much attention to the actual detail of the out-of-focus area; and often, even if it is drawn to their attention, they will see nothing much to praise or to damn in the way things are rendered. This is not to say that bokeh is meaningless: merely that it is possible greatly to overrate its importance.

Then again, it is not impossible to find examples of bad bokeh, as evidenced by the image on the right, which was taken with a 9cm f/2.2 Thambar. This is a rare Leica soft focus lens dating from the 1930s. It has a unique centre-spot screen for enhancing the soft-focus effect (by using only the softer peripheral rays, not the sharper central ones) and with certain kinds of subject matter this can lead to very nasty bokeh indeed: blurring of vision almost like sea-sickness, or a hangover. The answer is of course simple: avoid this sort of background when shooting with a Thambar.

Hollyhock

The peculiar 'blobby' bokeh of the Thambar is discussed in the text above and below.

Bokeh is often held to be intimately related to diaphragm shape and position, and as the Thambar shot on the right illustrates, this is probably an important factor. In particular, though, more diaphragm leaves mean a more circular aperture and therefore less opportunity for the out-of-focus image to go a funny shape. It also helps explain why the bokeh may change as a lens is stopped down. At full aperture, the diaphragm leaves seldom obtrude at all into the light path. Even so, it is almost certainly not the only factor at work.

hollyhock

What are the others? It is hard to say. The symmetry (or otherwise) of the lens design is certainly relevant; Geoffrey's definition, quoted above, specifically cites the Meyer Plasmat for its 'good bokeh'. Focal length seems not irrelevant, but that may simply be because a longer focal length has a smaller depth of field at a given aperture and subject distance than a shorter focal length at the same aperture and subject distance. Many zooms seem to have weird bokeh, with clear distortions such as thickening of the ends of what should be parallel-sided bars or batons. And then there are other distortions such as coma, which impose their own shapes on light sources in the picture. The pre-aspheric 35/1.4 Summilux which is Roger's favourite lens on film is often praised for its bokeh, but the coma is terrible.

 

tent plus three

Re-enactors

Bokeh is doubly important here. First, in order to preserve the vintage look you need a fairly shallow depth of field: if this picture were contemporaneous with the actors, it would have been shot on 6x9cm roll-film with a lens at a fairly wide aperture (f/4.5 or so) simply because the films of the day were so slow. Second, bad bokeh can be really evident in foliage and trees, with a nasty 'wiry' look. Though perhaps barbed wire should look wiry...

The first thing to bear in mind about bokeh, therefore, is that while it is a useful word and describes a recognizable (if not easily describable) phenomenon, it is partly a fashionable buzz-word, and it can be interpreted in widely different ways. What one person calls 'beautiful, swirly bokeh', another will see as queasy. We cannot quite see what either party means.

This leads immediately to the second thing, which is that you can't necessarily judge much about how you will like a lens from someone else's pictures, even if they are exquisitely printed in large formats. If you shoot the same sort of subject, under the same sort of light, then you may be able to glean a little information. Otherwise, you are only going to get a pretty vague opinion.

civil war

Likewise, you may be able to tell a modest amount from a picture on a computer screen, at very low resolution, but equally, there is an awful lot you are missing: a 10.1 megapixel picture, 2620 x 3904 pixels, contains a lot more information than a 600 x 900 pixel screen-filling image. Of course you can always do selective enlargements of part of the image, but at that point you are no longer seeing the whole picture, so (once again) the value is limited.

 

American Civil War re-enactor

What's the background? Dunno -- and that's the way it's supposed to be. Frances probably used a 90/3.5 Voigtländer Apo Lanthar on a Leica Bessa-T for this shot: not a super-fast lens, but one that will throw the background out of focus entirely adequately, if the background is far enough away. Even with a reflex and depth-of-field preview, you can't really judge what the bokeh will look like, and with a rangefinder camera, you've no hope at all. It is all down to experience, and to looking really hard at both your subject and your pictures. Probably Ilford XP2 Super; print on sepia-toned Ilford Multigrade Warmtone.

The third important point is that bokeh applies at all apertures. At f/4.5, the Voigtländer Apo Lanthar was hardly a speed king, though as compared with the f/5.6 of the Schneider Symmar which was probably its nearest competitor, it was no slouch either. But there is a pleasant roundness to the image quality, and it was the first lens where we ever heard anyone (the late Colin Glanfield) refer to 'the quality of the out of focus image'.

Shooting fast lenses at wide apertures 'for the bokeh' is therefore to misunderstand the term, and, all too often, to compose an image which might very well work better with more depth of field.

The fourth point is that if you shoot 'deep field' on a tripod, or use wide-angles at moderate apertures and distances, or if the subject is fairly flat, you may never see much in the way of bokeh anyway.

Grand Canal, Venice

Even though it was only shot as a JPEG (Roger was running out of memory space on his last SD card), this is pretty sharp from back to front. He used his M8, but has completely forgotten which lens he used. It was probably either a 50/1.5 Zeiss C-Sonnar or a 35/1.4 Summilux pre-aspheric. Both are noted for their bokeh but aficionados of the term discern far more differences than we do, especially at modest apertures and high shutter speeds: this was probably about 1/250 at f/8 or so.

The image has been post-processed in Adobe Photoshop for a 'vintage postcard' look, but the shape is wrong: it should be less square

venice

THE BOTTOM LINE

Bokeh is one of those things like grey cards and the Zone System in that while it is very useful in its place, it attracts fanatics and people who think they know a great deal more about photography than they do. Many are inclined to attribute everything good in photography to their pet hobby horse, much like those who believe in gurus. Don't be intimidated by bokeh, and don't overrate it if it's not important to you. If it is important to you, then the very best of luck to you, but remember that others may not share your opinion of its importance.

 

pelopponese

Pelopponese

Roger shot this with a 6x12cm Horseman back on an MPP 4x5 inch camera using his 150mm Voigtländer Apo Lanthar lens; when he bought it in the 1980s, Colin Glanfield was the first person we ever heard remark on the quality of the out of focus image. The trees in the foreground are indeed slightly out of focus, even though he was shooting at f/16. We find it highly disputable that the subtleties of bokeh (or indeed anything else much) are ever going to be visible on a computer screen, which may be why so many people go for the crudest possible bokeh shots, with ultra-fast lenses at full aperture even if they then have to use ultra-high shutter speeds and neutral density filters.

 

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© 2010 Roger W. Hicks