No blurry background

cartersmommy1

I have my camera on A setting and have turned it down to f/3.5 and the background isn't blurry at all. I have the 18-55mm lens kit, and the ISO is set at 400. What am I doing wrong?

bruto

The blurry background, which is caused by shallow depth of field, depends on three things.

The first is aperture. No more can be done with this lens. The A setting is appropriate. You've done all you can here.

The second is closeness to the subject. The closer your subject is, the shallower your DOF. Along with this, what you want blurred must be as far out of the depth of field as you can get it. The more separated the better. If you put a person up against a brick wall, the wall will be sharp. If you put the person ten feet in front of the wall, the wall will be at least a little blurry.

The third, and one of the most important, is focal length of the lens. The longer the focal length, the shallower the DOF. Unfortunately, since the kit lens gets slower at 55mm, that does not help. But generally speaking, you're best off going long at f/5.6 than short at f/3.5. This, by the way, is why the smaller the camera's image format, the harder it is to get DOF blur. A little pocket camera with a tiny sensor gets a normal viewing angle from a very very short focal length, and because of this, almost everything is always in focus.

It is possible to get some background blur with this lens, but it will always be a challenge. Try to isolate your subject as much as possible from the background. When out doors, try lowering your point of view, and shooting a bit more upward, so that far objects make up more of the background.

It also helps (when possible, which it is not always) to try to find background objects which are abstract and cannot readily be identified.

Some time ago, I did a little side by side comparison to help illustrate a couple of points. In this I used a 50 millimeter and a 35 millimeter lens, both set to an aperture of f/2.8 That is, of course, wider than you can achieve with the kit lens, but it may help anyway. The subject is framed more or less the same in both pictures. To do this, I had to move the 35mm lens closer, which decreased DOF some. But you will note that even though the 50mm is further away, it ends up with slightly more blur. When you can choose, go for longer focal length over closer distance. Note also the change in the relative size of objects in the background.

http://jmp.sh/Y8Akv4C

If you want the best out-of-focus blur, your best bet is a faster prime lens - the 50mm f/1.8 is a very nice portrait length for a DX camera. The 35mm f/1.8 is more versatile, but not quite as good for portraits. An 85mm is luscious, but difficult in close quarters. Your second best bet is a longer zoom. If you're looking to increase your reach anyway, you will find that something like the 55-200mm zoom lens, though slow, will give pretty good blur when it goes longer. If you can stand far enough back, the effect of longer focal length shows up well.