Blurred Backgound

[trobinson]

Hello everyone,

Ok, so here I am... I have a Canon Powershot XS 20 IS and I "thought" I knew a little about photography but I guess I don't. I am trying to do something as simple as blurring the background on my pictures. I have read several articles on it, and "thought" I knew the basics of apature, shutter speed, and DOF.... I just can't get the background to blur. As a matter of fact I set my camera up... took pictures starting at f2.8 through f8.0 from the exact same distance and I can't tell any difference in the pictures. The background never changed. I mean I thought in "Av" mode I should be able to set my f'stop to the largest opening, which on my camera is f2.8 and it would blur the background. Is that not right???

Somebody please explain to me in detail what i'm doing wrong. I guess i'm dumber than I thought. Someone give me an assigment that I can try with step by step details that if I do it right the background should come out blurry. Thank You

[atulsc]

that's one of the problems with point and shoot cameras, they give very less control over the focussing and DOF. Chosing the smallest possible f number is the right thing to do, but then it would depend on how close to the subject you are(focusing distance) and what's the focal length you are using.

So with maximum aperture set, also set the close to maximum focal length available to you and get as close to the subject as you can.

here is one of the threads i'd posted earlier, you can see that i applied all the these things to get the DoF, i did it with a 18-55mm kit lens on D60 you can get the EXIF if you follow the links to my picasa and try those settings you should get it
http://digital-photography-school.co...eping-tom.html

[prabbit237]

I am by NO means an expert in these things but......Basically, all you need to look at is the DOF (depth of field.) That is all that's needed to decide if the background (or foreground) will blur or not. If the DOF for specific settings is from 10'-30' with a middle of 17', the at 17' away, yer in perfect focus.Anywhere from 10-30' away, yer in pretty good focus. But if yer 2" away or if yer 200' away, yer out of focus. The larger the apeture (lower f stop) or the closer to the camera the focal point, the shorter the depth of field. But basically, if you have a DOF from 10-30' and the person is at 15' and the background is around 30-35' away, you won't see any (or very little) blurring, even though it's "in the background" (being in the background doesn't guarantee that it's not still in the DOF range.) In fact, at a focal point of 15-20', yer starting to get a far end of the DOF that's getting pretty far out there and approaching "to infinity and beyond."

As an experiment, get someone about 2' from the camera (don't worry about framing and composition here. Just get them to fill half of the frame) and have the background 40-50' away. Set the camera to f2.8 and snap a pic. Either it'll focus on the person and the backgrough will be very out of focus OR it'll wind up focusing on the backgrough and the person will be very out of focus (there's ways to force the focus in a case like this but for this experiment, it doesn't matter.) Either way,you'll see the DOF at work. Then try and find a field of flowers or grass and get maybe 8-12" above the tops and position the camera where you're seeing something maybe 8' ahead of ya in the middle of the frame. Open up to f2.8 and snap the pic. You'll see the stuff you aimed at in perfect focus (I hope*grin*) and then stuff closer or further away getting more and more out of focus.