Camera question

[MelissaP]

I have the Canon Power shot SX130 IS 12 X Optical. Now it's a great little camera and isn't the exact camera I wanted, but I do enjoy it. I would like a DSLR soon the Rebel to be exact. Which is something I'm saving up for. Now my question is this.

Is it the camera or an edit with a program that does the focal? Like say you are taking a picture of a person, the person isn't blurry or out of focus, but the background is out of focus, is that the camera that does that or is that a program edit that does that?

If it is the camera, how can I do it without a dslr? I notice that I can take a few pictures where it does it. I just don't know what I'm doing to do it lol.

If it is a program edit, can someone explain how? What programs? I have access to Photoshop Elements, Photoshop cs5, and lightroom. I also use picnik.com

[zenandzen]

Have a look at this and you will understand a bit more about what it is - Depth of Field.

Online Depth of Field Calculator

[dlambert]

Take a look at this:

http://photo.stackexchange.com/quest...as/10001#10001

You can achieve this look with a P&S, but it's not as effective as with a DSLR and a good lens. The link that zenandzen posted will give you a very precise answer once you understand the idea of depth of field.

[inkista]

Originally Posted by MelissaP

Is it the camera or an edit with a program that does the [thin DoF]?

Camera. And lens. And you.

There are a bunch of factors really that affect your DoF. They are:

1. aperture. The larger your aperture (smaller your f-number), the thinner the DoF will be.

2. subject distance. The closer you are to the subject, the thinner the DoF becomes. This is why macro shots will have the blurred background, but landscape shots rarely do.

3. subject-to-background distance. The closer your subject is to the background, the harder it is to blur the background out. If you stand someone up against a wall, chances are the wall will be in focus, too. If you stand someone 10' in front of the wall, you have a hope of blurring out the wall. 20', you have even more chance.

4. focal length. The longer your lens, the thinner the DoF will be. The shorter the lens, the deeper your DoF will be.

P&S cameras are are a disadvantage on most of these situations. Because the sensor is so small in a P&S camera, proportionately, you have a very small lens (while it may say you have 20x zoom and a 450mm equivalent, chances are your lens is actually in the 5mm-100mm range. This is short. Really short at the wide end). The fixed lenses tend to max out around f/2.8, and only at the wide end. And the subject distances are proportionately huge.

Also note that 1, 2, and 4 play against each other. The more you zoom in, the less aperture you're going to have to work with, and the farther away from your subject you're going to be...

People buy point and shoot cameras because, well, they want to point and shoot. They don't want to have to learn how to focus a camera accurately or risk the chance of getting an out of focus shot. Having a huge DoF helps with that. It makes pictures sharp.

If it is a program edit, can someone explain how?

You can fake having a thinner DoF in post-processing by using a mask and blurring to soften the background. But you have to know how DoF would behave in that situation and blur things out appropriately. Gradient masks and depth masks are one way of controlling the blurring. But it's relatively difficult to make it look natural and not like you've been photoshopping something. It's much easier to do in-camera. We went through a debate on this not so long ago.