If any of you have ever wondered what they are talking about when you see a lens reviewer comment on the "bokeh" of a particular lens, the first thing to know is that it is a very subjective notion. Basically, when the out of focus areas of an image are distracting rather than unobtrusive, structured is not as good as creamy and blended.

It's not an invisible phenomena, but it isn't necessarily apparent on every photograph, depending somewhat on the conditions, the background, etc.

Here's an example of "bad" bokeh, taken with my Nikkor 28-300mm on my D700:



In the photo above the out of focus area is very distracting, the points of light are turned into distracting ovals with sharp edges, etc. on what would otherwise be a decent photo. It's also one of the disadvantages of a "slow" lens. The above photo was taken at f/5.6, as open as this lens gets at 300mm.

And here's an example of "better" bokeh, taken with my Nikkor 300mm f/4 lens, but also shot at f/5.6, on my D7000:



Obviously, the out of focus areas are much more diffused in the second pic and much less distracting overall. This, I think, is what they mean by good bokeh.

It's more of an issue in portrait photography, where lenses get reputations for "good bokeh" and get sold solely on that basis. The 85mm prime lenses frequently get cited as having the best bokeh. Here's an example with my Nikkor 85mm f/1.8 on my D700:



The background just sort of melts away at f/2. In this admittedly very subjective analysis, the Nikkor 85mm f/1.4 G and the Nikkor 200mm f/2 are considered to be the best Nikkor lenses for both sharpness and bokeh. They are, of course, very expensive, as well as big and heavy. The 85mm f/1.8 like mine is considered to be very close in performance to the other two, but costs closer to $700 new. I bought mine (used) for $500. If you like to take "head" shots of family, friends, or people in your hunting party, I encourage you to consider having a lens like this in your camera bag. They are fast, sharp and have excellent bokeh. An 85mm allows you to fill the frame with a head or two without being in their face, since from 6 feet away you get a good perspective. Very good for pictures of just about anybody.

Thank you !

Before anybody thinks I've relegated my 28-300mm zoom to the overpriced P.O.S. category of lenses, no way. To date, that is probably the only photo I've ever taken with it which produced those results. This was taken with the same lens on the same camera last December, and I'm happy with the results:




No bad bokeh here.

Bokeh = optical moire ????

Changing the aperture setting of an observed moire & re-shooting alleviates the problem in most cases............if you can't afford solving the problem with dollars.
Optical moire is an unfortunate confluence of patterning of the out of focus background, the optical magnification of the image & lens characteristics.........its not just caused by one of those 3 parameters.
the effects of changing aperture is typically enough to mitigate the unfortunate confluence of parameters.

If you have a lens that exhibits the problem , adopting a practice of multiple shots with varied aperture ( when possible) usually results in one with good 'bokeh'.

dollars in the right place can most always solve a photography problem.

lovely shots showing good & bad bokeh.

There are other fields of artistic endeavour that deliberately create moire patterning.

quote:

Posts: 5908 | Location: Rambouillet, France | Registered: 25

The implication is you cannot have a picture without 'bokeh'. Your picture of the hartebeest has no apparent 'bokeh' as the background is in perfect focus. Aren't you really referenceing an out of focus background which is a product of depth of field which is less and less as the lense reaches maximum aperture. This used to be apparent when lenses had a depth of field scale on the focusing ring of the lense. The shape of the figures produced can also often be the product of the number of blades of the aperture and how much of a true circle they form. You can use it selectively as you choose in most cases. The first picture shown here is partially bad because of the predominate color and reflective quality of the background. The second picture does not have nearly so much green in it which I assume is from leaves. Since the Eagle in the first shot seems to be static and the tree is also you would certainly believe you would not have to use the largest aperture to achieve the shot as it seems a brightly lit subject. Just my appraisal,of course, which is a purely personal opinion.

It is definitely the out of focus area to which the term bokeh is applied. A picture which doesn't appear to have an out of focus area, or appearing to be in-focus at all distances (which is only an appearance, not a reality, due to the circle of confusion) would not have bokeh. I'm certainly not an expert on optical phenomena in photography, but there is stuff on the web anybody can consult.

https://en.wikipedia.org/wiki/Bokeh

The background area in the photo of the hartebeest is definitely out of focus. For some subjects the intent is have an out of focus background to better highlight or delineate the principal subject, which is one of the advantages of fast lenses because you have that option. And of course some lenses have such a shallow depth of field that you don't have much choice, as with telephoto lenses, anything not in the focal plane will appear out of focus. Obviously this is not the case with very wide angle lenses, especially stopped down to f/16 or more.

I don't study the physics of optics, I just like to take pictures. But for those who love mathematics there is this you can chew on.

https://en.wikipedia.org/wiki/Circle_of_confusion

quote:

Originally posted by DenisB:
Bokeh = optical moire ????

Changing the aperture setting of an observed moire & re-shooting alleviates the problem in most cases............if you can't afford solving the problem with dollars.
Optical moire is an unfortunate confluence of patterning of the out of focus background, the optical magnification of the image & lens characteristics.........its not just caused by one of those 3 parameters.
the effects of changing aperture is typically enough to mitigate the unfortunate confluence of parameters.

Moiré is not bokeh. Moiré is superposed patterns (usually in focus, not out of focus) which cannot be "resolved" by the sensor, and are visually very different from the quality of the out-of-focus portions of the image. See this:

http://photographylife.com/what-is-moire

Interesting review of the subject of bokeh in photography in a recent PictureCorrect


What is the Bokeh Effect in Photography?

I would add that the camera being used, or camera/lens combination, determines how easy or hard it is to get a satisfying bokeh effect.

As a general rule, the smaller the physical size of the sensor (not pixel count), the harder it is to get any out of focus areas. So a point and shoot will be difficult, but a full frame DSLR will be relatively easy.

This is because the combination of smaller sensors and their associated lens systems have greater depth of field. You optically cannot get the background out of focus as easily.

Another way to say it is that f3.5 for a full frame camera does not have an equivalent depth of field as f3.5 for a small sensor camera. There is an optical tradeoff when you reduce sensor size.

I ran into this when I started building an Olympus system on their mirrorless EM5 boby. The equipment is 1/3 the size of my full frame Canon gear, so it is easy to carry. But I had to relearn depth of field control even though I have fast lenses for the Olympus.

Jeremy

quote:

Originally posted by farbedo:

As a general rule, the smaller the physical size of the sensor (not pixel count), the harder it is to get any out of focus areas. So a point and shoot will be difficult, but a full frame DSLR will be relatively easy.

This is because the combination of smaller sensors and their associated lens systems have greater depth of field. You optically cannot get the background out of focus as easily.

Jeremy

Very true and not only that, the transition from in-focus to out-of-focus is sometimes not as abrupt, making it a challenge to get that subject isolation effect I like. It does have the advantage however of making it easier to get in-focus shots with a telephoto lens when the effect may not be wanted.

Something else about good versus bad bokeh I would like to mention as follows: in some instances it's difficult to tell what is good or bad bokeh. For example, have you seen the bokeh a 50 to 85mm helios lens creates, plus the background rendition in portraiture photography?
This is a very old design of a Russian manual lens that is still in production:

https://www.google.com/search?...sAQ&biw=1202&bih=662

Had to add that a good bokeh versus a bad one is a subjective thing, specially with lenses such as the Helios above. But there is a lens that is talked about as making the subject pop (sort of 3D) while providing a buttery-smooth background, and that's the Canon EF 135mm f/2.