Digital Photography School Blog

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how to achieve blurred background with clear object(using aperture and depths of field)?

I am a photography beginner using a sony T100. Can anyone tell me how to achieve the effect of blurred background with clear object(the last 2 pic of the flower) as shown in the link:

http://digital-photography-school.com/blog/aperture/

i think it has someth to do with aperture and depths of field. But i think my camera cannot be adjusted manually...can someone with t100 tell me what to do!

thanks alot!!!
i don't think i have av mode(the aperture-priority mode right?) so i can't manually adjust the aperture...how do i achieve large aperture....i tried a few pics with different modes and i keep getting F3.5, 4.0, 4.4....
Sadly i can only adjust ISO and exposure....
Oh ya and the modes i have are high sensitivity, soft snap, twilight portrait, twilight, landscape, hi-speed shutter,beach, snow and fireworks.
Help! i still can't get that effect with all the comments here.... i need more comments. but thanks to the people who helped me out earlier.

It's going to be darn hard to "de-focus" too much using a digital camera while keeping the main subject in sharp focus. The smaller the sensor, the greater depth of field you will have. Generally speaking, the smaller the camera, the smaller the sensor. Your T100 has the smaller sensor - 1/2.5". Most of the pictures you take with a digital camera are quite sharp from near to far distances and there is a reason for that which I will explain.

While we speak in terms of the 35 mm equivalency of digital lenses, don't forget that the digital sensors are usually smaller than a full-format 35 mm frame. Most of the more popular point and shoot cameras - including your T100 - have the smaller sensors. It's only about 5 mm wide and 4 mm high. The lens on required to cover that angle of view is an ACTUAL 6-17 mm zoom lens. At these focal lengths, the background is going to almost always be in pretty sharp focus.

In other words, if you WANT to defocus the background, you are going to have to work pretty hard at it. You would have to zoom to the longer end of the lens and set the aperture open as wide as it will go, if your camera even allows you to control the aperture, and get pretty close to your main subject while having the background a fair distance away.

Put your subjects quite a distance in front of any background that will be visible in your photo. You could use a garden of flowers and stand your subjects 20 yards or so in front of them. As suggested, try the portrait mode to shift things towards a larger aperture, zoom the lens out all the way, and move YOURSELF backwards or forwards in order to frame the picture as you would like it.

The bigger the sensor, the easier it will be to achieve pleasing bokeh. This means moving to a dSLR, which all have sensors about 20 times bigger than the typical P&S digicam. If you want to really go for brokeh (very bad pun intended), you can get a Canon 5D and you will get exactly the same effect you are accustomed to in a 35 mm camera, since the sensor is the same size as 35 mm film.

Here is an example with a point and shoot camera, although it does have the larger sensor (1/1.8") that makes it easier to blur the background. Even though this is macro mode and f/2.8, where the background should blur the most, it's not terribly blurry because it's relatively close to the subject.

http://www.flickr.com/photos/samfeinstein/872732755/

Here is an example with a point and shoot camera, so it CAN be done. The background is much farther away, though, and this is the larger sensor size.

http://www.flickr.com/photos/samfeinstein/843563558/

Compare that to this image, though, which has a similar subject-to-background distance. The SLR has the obvious advantage.

http://www.flickr.com/photos/samfeinstein/408446616/

Wikipedia does pretty well on the subject of depth of field. See: http://en.wikipedia.org/wiki/Depth_of_field

See also: http://www.photo.net/learn/optics/dofdigital/

Perry's Joint in Pasadena


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