How do you get the blurry background effect?

[larry909]

What do you need in a digital camera to get that effect where you see the object in focus and the background is blurry?
Is it manual aperture and shutter settings? So if a camera has manual aperture and shutter settings it would be able to do that?

 

[photo1x1.com]

Hi and welcome to the forum!
You need to set the aperture. You can do that in aperture priority. How blurry it is going to get depends on a few factors like

• Maximum aperture of your lens (the lower the number the better)
• Focal length: the longer the better
• Distance background - subject: the further the better
• Distance camera - subject: the closer the better
• Sensor size of your camera - the bigger the better

If you are interested, I deal with some of the factors in my "effects of aperture" series:

 

[jaomul]

When you focus on something a certain area front and back is very much in focus while the rest starts to get blurred. This effect is more pronounced if you focus on something close and the background is farther away, it is even more pronounced with smaller aperture numbers (larger aperture).

You'll often see portraits taken with an 85mm lens with an aperture of say f1.8 and a lot of background is oof.

Google Depth of field for a more detailed explanation

 

[Designer]

So if a camera has manual aperture and shutter settings it would be able to do that?

In short; no.

The list in post #2 above is cumulative in nature. Only one of those things by itself might not achieve the blur that you want. Do all of those things to maximize the effect.

Also, it's not just digital. Film can do it too (substitute "film" for sensor).

Also, not every digital camera is capable of producing the desired amount of blur. In that list, you really have to maximize all or nearly all of the factors in order to get a blur. And most of the time the gear (lens, sensor size) doesn't come cheap.

Also, there is nice smooth blur (sometimes called "bokeh") and then there is jittery, figured blur that is just not pleasant to look at. The smoothness of the blur is an inherent quality of the lens chosen, and cannot be "adjusted". It is what it is.

 

[Tomasko]

@Designer , that "jittery, figured blur" is still called "bokeh".

 

[Designer]

@Designer , that "jittery, figured blur" is still called "bokeh".

No, that's the OPPOSITE of "Bokeh". Bokeh is creamy, dreamy, smooth blur with no figure at all.

 

[Tomasko]

@Designer.

Let's start with wikipedia: Bokeh - Wikipedia
In photography, bokeh (originally /ˈboʊkɛ/,[1] /ˈboʊkeɪ/ BOH-kay — also sometimes pronounced as /ˈboʊkə/ BOH-kə,[2] Japanese: [boke]) is the aesthetic quality of the blur produced in the out-of-focus parts of an image produced by a lens.[3][4][5] Bokeh has been defined as "the way the lens renders out-of-focus points of light".

photographylife.com: What is Bokeh?
Basically, bokeh is the quality of out-of-focus or “blurry” parts of the image rendered by a camera lens – it is NOT the blur itself or the amount of blur in the foreground or the background of a subject.

B&H: Understanding Bokeh
“Bokeh” is an English word that is a translation of the Japanese word “暈け” or “ボケ” that means: blur—specifically out-of-focus blur. So, why not just use the already established word “blur?” Because the simple English word “blur” can be applied to motion blur as well. Also, the word bokeh also encompasses the Japanese word “ボケ味“ meaning “blur quality.” So, bokeh is more than the blur, it is a word used to describe the aesthetic quality of blur.

Nikon: Bokeh for Beginners | Achieving Bokeh in Photographs | Bokeh Effect Tips & Tricks from Nikon from Nikon
Simply put, bokeh is the pleasing or aesthetic quality of out-of-focus blur in a photograph.


So yes, I believe you can talk about bokeh in context of a not really pleasing/jittery/whatever background blur. You wouldn't call it "a pleasing bokeh", but...

 

[fmw]

One correction. The size of the sensor has nothing to do with depth of field. It is all about lens focal length and aperture as well as distance. Smaller sensor cameras tend to use shorter lenses so that is where this sensor size misconception arises.

 

[fmw]

@Designer , that "jittery, figured blur" is still called "bokeh".

No, that's the OPPOSITE of "Bokeh". Bokeh is creamy, dreamy, smooth blur with no figure at all.

No bokeh is nothing more than the appearance of out of focus areas in a photograph. Bokeh can be creamy or horrible and you can describe it any way you like since it is subjective.

 

[photo1x1.com]

One correction. The size of the sensor has nothing to do with depth of field. It is all about lens focal length and aperture as well as distance. Smaller sensor cameras tend to use shorter lenses so that is where this sensor size misconception arises.

I know what you are referring to, so yes and no. But using the same 85mm lens with the same aperture setting and the same crop of the subject with both full frame and crop sensor would result in a much more blurred background on the full frame image, because you are closer to the subject.

 

[Designer]

So yes, I believe you can talk about bokeh in context of a not really pleasing/jittery/whatever background blur. You wouldn't call it "a pleasing bokeh", but...

Sheesh!

Whatever.

That would be like calling "rap" music.

 

[fmw]

One correction. The size of the sensor has nothing to do with depth of field. It is all about lens focal length and aperture as well as distance. Smaller sensor cameras tend to use shorter lenses so that is where this sensor size misconception arises.

I know what you are referring to, so yes and no. But using the same 85mm lens with the same aperture setting and the same crop of the subject with both full frame and crop sensor would result in a much more blurred background on the full frame image, because you are closer to the subject.

Lens focal length and aperture. Subject distance. Nothing else. You can use the 85mm lens at any subject distance. The sensor has nothing to do with it. You are saying that subject distance affects depth of field and, indeed, it does.

 

[TCampbell]

Bokeh refers to the "quality" of the blur (good or bad).

Anyway... the three things that go together to produce strong out of focus blur are:

1) LOW focal ratio adds to the blur
2) LONG focal length lens adds to the blur
3) CLOSE subject, distant background (if the background is very close to the subject then the difference in focus between subject and background won't be so strongly different.)

Many lenses are just not capable of producing a very strong blur. Most DSLR cameras come with a "kit" lens and it's usually something an 18-55mm zoom with a variable focal ratio which can be as wide as f/3.5 at the short focal length (wide angle) end, and f/5.6 at the long focal length (narrow angle) end. Unfortunately f/5.6 at 55mm will produce very little blur and likewise f/3.5 at 18mm will also produce very little blur. It's a struggle to get much blur out of these lenses unless you resort to extremes such as putting the subject at closest possible focus distance and putting the background very far away.

It's much easier to do with longer lenses.... 85mm and up and hopefully with a low-ish focal ratio (such as f/2 or lower). You'll even get a little blur with a 50mm lens and a low focal ratio (f/1.8 or f/1.4, etc.) but as you get to lower focal lengths it becomes very difficult to produce much in the way of a pleasing blur. I have a 14mm f/2.8 lens and that lens wants the whole world to be sharp almost no matter what I do. The most I can do is get enough blur to make it look like I just barely missed focusing accurately (the blur isn't strong enough to look intentional.)

As you get to much longer focal lengths (e.g. 200mm) then you can even get pleasing blur at f/4.

I have a 135mm f/2 lens which is basically a cream machine (LOADS of background blur) and a 300mm f/2.8 that produces so much blur that diabetics should not look the photos lest they go into insulin shock from all the sweetness! (Ok, I'm kidding... but just a little). The point is, LONG lenses with LOW focal ratios produce a LOT of blur when you have a CLOSE foreground subject and a DISTANT background (not close to the subject).

This is 300mm at f/2.8. In the (distant) background, there is a patio and people are having tea.

Do you see anyone having tea? Neither do I. But since I took the photo, I know that they were there. This is an example of extreme blur. Sometimes you don't want so much blur that the background is no longer recognizable. I have other photos where we specifically wanted soft blur on the background but wanted to make sure you could actually recognize the background subjects for what they were.... in those cases you back away from using the widest possible focal ratio and use something slightly narrower.

BTW, it is also possible to "fake" the background blur using products such as Photoshop.

The blur in this background is fake:

Here's the original (as shot):

In the original you can read the wine bottle ... Silver Palm (a very pleasant cabernet). But this was done for a restaurant who wanted the attention on the food -- and the wine is there to help support the mood. So we want a bottle (for the mood) and we want you to "recognize" the bottle... we just don't want you to be able to read the bottle.

To produce this, I had to use Photoshop using masks and layers... the top layer has a photoshop "lens blur" filter applied but the background does not. There's also a mask to let me selectively reveal the non-blurred plate of food through the "blurred" upper layer and I had to very carefully feather the blur out from around the edge of the plate to create a believable transition. It took a while to do.

The blur was also done to match the intensity of blur in other shots that were going to be used in the same articles.

So why not just shoot at the same f-stop using the same lens as the other images which had the correct "as shot" blur??

This was the only dish on a wide rectangular plate and composed at an angle. When I used the same f-stop as the other shots, the food (the main subject) was not entirely in focus the way we wanted. So we chose to stop down the lens to increase the depth of field, improve the overall look of the food and then "fake" the blur to match the rest of the photos in the shoot.

While I say it is possible to "fake" the blur (with an example), I have seen some really awful fake background blur. It took me several attempts to try to come up with a fake blur that could pass for natural blur (like all things in photoshop... it's a learning experience. )

 

[SquarePeg]

This is a great subject to experiment with to improve your understanding of dof. You have 4 main variables: focal length, aperture, distance from lens to subject and distance of subject to background. Set up your shot and change one variable at a time to see the effect on your background blur.

 

[SquarePeg]

@TCampbell gorgeous Iris shot! They're my favorite. I hope you have that hanging on your wall.