Does anyone know how to blur the background?

ainsley

I’m trying to take family photographs I want to blur the background. Does anyone know how to do this? Also if anyone has any good tips per child and baby photographs that would be great!

bruto

Blurring the background means, basically, having a shallow depth of field. Several things contribute to shallow depth of field.

The first is aperture or f-stop. The wider open the lens is, the shallower the depth of field. Whatever lens you're using, try to keep it as wide open as possible.

The second is focal length. The longer the focal length, the shallower the depth of field, so try to keep your lens at the longest focal length if it's a zoom.

The third, and a bit contrary to the second, is distance. The shorter the distance to the subject, the shallower the depth of field, so try to stay as close as you can (this is why a macro photograph has very shallow DOF while a landscape is fairly sharp all across).

Between those last two, focal length has a slight edge over distance. Between two photographs with the same subject size, one with a short lens up close and the other with a long lens at a greater distance, the long lens wins. In addition to the DOF advantage, a longer focal length will tend to compress perspective, making background objects both fuzzier and bigger. Some things become harder to identify and less distracting when they are enlarged behind a subject. A wall of trinkets which stands out like a sore thumb at wide angle may look pleasingly abstract when they are both bigger and fuzzier. e.t.a. a longer focal length will also tend to flatten faces a little, while short lengths will tend to emphasize depth, including long noses and the like. Portrait photographers often prefer a short tele to keep noses from looking exaggerated.

With regard to the subjects themselves, placement makes a big difference. Try to keep your subjects as far from walls and other distinctive backgrounds as possible. If at all possible (and it isn't always) try to shoot upward a little so that they are against far backgrounds and sky more than against local walls, buildings and trees. Remember in the end it's better to have a sharp subject well shown than it is to get the background right. Look for environmentally appropriate backgrounds, that either do not distract, or that accentuate what the subject is about. For a little excursion into "environmental portraits," look up the famous photographer Arnold Newman, who did not seek blurry backgrounds, but instead looked for situations in which the background told us more about the subject than just a portrait would.

If you're using kit lenses with relatively small apertures, there's only so much you can do, and you will never achieve the look that comes with faster more expensive lenses, but placement and care can help. Choose backgrounds that have little identifiable detail. Use the longest focal lengths available. You can get surprisingly good subject isolation (i.e. sharp subject, blurry background) if you have room to use a telephoto lens and stand back. Get up around 85 or more millimeters, and even an inexpensive kit lens on a DX camera will render nicely.

Of course if you get a more expensive lens it becomes easier. The 50 mm. 1.8, not too terribly costly, will give you nice portraits wide open, and is a great thing to have on a DX camera for this. Any 85 mm. lens will provide juicy subject isolation. But in the mean time, a good part of the creative process is in figuring out how not to need these things, and either to get subject isolation through placement, or to fit the subjects into their environment.

bruto

Adding a bit to this, I would throw in a couple of links to some of my favorite "environmentaL" portraits.

The first one is one of the most famous, early divergences from the old practice of posing subjects in a studio with props. This is Isambard Kingdom Brunel, and you don't even have to look him up to realize more or less what sort of man he was:

https://upload.wikimedia.org/wikipedia/commons/thumb/9/96/Robert_Howlett_(Isambard_Kingdom_Brunel_Standing_Before_the_Launching_Chains_of_the_Great_Eastern),_The_Metropolitan_Museum_of_Art_(cropped).jpg/220px-Robert_Howlett_(Isambard_Kingdom_Brunel_Standing_Before_the_Launching_Chains_of_the_Great_Eastern),_The_Metropolitan_Museum_of_Art_(cropped).jpg

the photographer here was one Robert Howlett, often credited as a pioneer.

Above, I mentioned Arnold Newman. Here is a page of his portraits, mostly of famous artists of his time. The one of Stravinsky at the piano is often considered one of the best portraits of its type.

https://arnoldnewman.com/portraits