How can I maximise that “blurry background, sharp subject” (bokeh) effect?

Question

I know that it occurs when there's a shallow depth of field, but what are the various ways I can increase this effect in my photos when I'm taking them?

Note that I'm not asking how to use an editing program to achieve this effect after they've been shot.

Answer 1

Here's the list of things that influence depth of field the most (in this particular order):

1. Subject distance, the closer the subject is, the shallower the DOF (think of macro)
2. Focal length, the more millimeters, the shallower the DOF
3. Aperture, the smaller the f-number, the shallower the DOF

Answer 2

Ultimately, you want a shallow depth of field, which means a low fstop number (f/2.8 for example). The lower the fstop number, the more light that gets in, so in order to expose correctly, you need to increase your shutter speed (1/1000 is better than 1/25), lower your iso (100 is better than 400), and if all this is not enough, add a neutral density filter to reduce ambient light, so that you can further open up your aperture.

Answer 3

It's more complicated than just depth of field. You can have two photos with identical depth of field, but one can have more background blur than the other. In addition to background blur, there is also "bokeh", which describes what kind of blur there is. Check out this article which describes it in detail, and gives you a tool for calculating the various parameters.

Answer 4

While using shallow depth of field is the most common technique to get blurred background, there are some other ways:

• using plain background so it would not need any blurring
  • set up your own background - you'll have full control over color and pattern
  • shoot against sky or some other plain surface (longer lens will help you by having smaller segment of background in frame)
• shooting with decreased visibility
  • shoot under water
  • shoot during strong rain or snowstorm
  • misty weather (you'll have best chances and light in mornings near sunrise)
  • create smoke or fog behind subject (e.g. fog machine or an upwind bonfire)
  • set up lighting and camera settings so that while subject is correctly exposed, background is underexposed - detail in dark areas is less discernible for a human eye

• using motion blur

  • use flash to light up your subject (avoid spilling light on background), deliberately move camera during rest of exposure (this will not work well with dark subjects)
  • shoot with longer exposure against a moving background (a vehicle, moving water, birds flying past etc)

  • with a moving subject, use longer exposure and pan with the subject

  • or switch roles - move the camera, keeping it aimed at a steady subject

• using specialized optics
  • a Soft Spot filter
  • a lens with Defocus Control
  • a Lensbaby

Answer 5

Obviously, smaller f-stop means shorter depth-of-field, so I'm not going there.

There are a couple of things you can do: 1) Remove the subject from the background as much as possible. How much will depend on the lens and aperture you can use. 2) Use a longer lens. Longer lenses have more narrow DoF.

Hope that helps.

Answer 6

Use a large aperture (small F number) when you take a photo. The larger the aperture the narrower the depth of field will be (compensate with with a shorter shutter speed). In addition you can try to vary the distance between the camera and the subject. The shorter the distance, the smaller the DOF will be.

Answer 7

If you want to increase this effect when making photos, then shoot on the longest focus end and with smallest possible aperture value (F number).

If you are talking about the post production, then in Photoshop you can use layer with gradient mask, copy the main layer, apply any blur filter to it, then use gradient for the mask. Here is the lesson for this technique. If you have a landscape shoot from the high point, then you can apply 2 gradients on top and on the bottom leaving the center of the image focused and sharp so that it looks like toy model.

Answer 8

The wider your aperture, the smaller your focal depth will be. So if you can shoot with a fast lens and use aperture priority to use the most open aperture setting possible you will increase this effect.

Assuming you have already taken the photo and everything is in focus, you can use software such as photoshop to select everything in the image you want to be blurry and apply a blurring filter. You can take it a step further and create an alpha layer to vary the amount of blur with the depth of the image. This will take longer but result in a very nice effect.

Answer 9

Apart from aperture and focal length, depth of field also decreases with camera-subject distance. So get you subject as close to the camera as possible.

Answer 10

There are also special lenses that don't actually have huge aperture, but that have bokeh that looks like they had. These are specifically engineered to blur the background.

The one of them I know is Sony 135mm f/2.8 [T/4.5] STF: http://www.photozone.de/sony-alpha-aps-c-lens-tests/390-sony_135_28

When fully open, the amount of light getting in equals to f/4.5 lens, but bokeh is like it was f/2.8.

Answer 11

You can also apply the 'Brenizer Method'. It is a hybrid solution that can produce outstanding shallow DOF images. See tutorial at ryanbrenizer.com. You still need post-processing though (and Photoshop works really well for this) to achieve final result.

Answer 12

First of all, start by ignoring all the answers here that talk about depth of field. You are after background blur which, although somewhat related, is really not the same thing as depth of field. Be aware that most people mix this two notions.

The two main factors affecting background blur are:

1 – Framing

The tighter you frame (the bigger the subject in the viewfinder), the more background blur you have. If you frame twice as tight you get double the original background blur.

2 – Diameter of the entrance pupil

You get this by dividing the focal length by the F-number. For example, a 85 mm f/1.4 (when used at 1.4) has a 61 mm entrance pupil (which is plenty). The larger the entrance pupil, the more background blur. Double the diameter and you get, again, twice the original background blur.

The distance to the background does not really matter as soon as it is significantly larger than the distance to the subject. If this condition is not met, then start worrying about depth of field. Other factors such as focal length, subject distance, crop factor, etc... have no effect as long as you compare pictures taken with the same framing and same entrance pupil diameter.

Answer 13

You can find a little tool at http://howmuchblur.com which can give you some additional feeling for the subject. With this tool you can compare different lenses, cameras, and subject sizes and see a visual comparison between their ability to blur the background.

Answer 14

Bokeh is controlled by depth of field, the shallower the depth of field, the more bokeh effect you will get. So how do you get a shallow depth of field? The quickest way is to move the subject further away from the background. Combine that with a zoom lens, which moves you further away from the subject and you'll start to see more bokeh. The ideal way, however, is to purchase a lens with a larger aperture (think f/1.2 - f/1.8). If you shoot Nikon and are on a budget, I highly recommend the Nikon 50mm f/1.8D.

Answer 15

For shallower depth of field, increase the distance between the subject and the background. Greater the distance between your subject and the background, the greater will be the blurring effect - sharp subject.