Focused Image...Blurred Background?

[smilesarepriceless]

My Canon 30D is coming in the mail anyday.. (YIPEEE)) and saying I am a newbie is an understatement..This is my first SLR and I want to be prepared and learn QUICK how to get some wonderful bday pics of my daughter.

What I have admired most of pictures of peers taking children's pictures is when the focal point of the child ( is in focus) and behind the child or whatever is in the background appears blurred/fuzzy.

Can you tell me the technical term for this and how I can go about doing it? Having the technical term will at least help me look for tutorials..Thanks!:thumbsup:

[Canuck935]

You'll want to read up on "Depth of field" or I've seen it abbreviated as dof a lot. Basically it's using combinations of aperature and focal length to control how much distance in front of and behind the focal point will look focused or look blurred.

Here is a link to the photography exposure guide in the learn section of photographyreview.

http://www.photographyreview.com/exposureguidecrx.aspx

This is a good start as it explains the 'basics.'

[another view]

Depth of Field (DOF) is it. With this shot, you could have used a larger aperture like f4 and made the DOF much smaller. With a wider aperture like this, a smaller area is in focus - instead of a couple of feet from the camera to infinity being in focus you'll have an area that's in focus from (rough guess) 3' to 8' by focusing on the child's face. How much DOF you have depends on the aperture (f-stop) as well as a few other things but that will get you started.

Having a small DOF does make focusing more critical. With a DOF of 2' to infinity, focusing isn't as critical because so much is in focus (however that doesn't mean that you should be sloppy... ). With a small DOF it's more critical to focus on exactly the area that you want to be the sharpest.

One thing to realize about DOF - there's no absolute magic distance where something goes from out of focus to in focus, or vice versa. It's based on "acceptable" sharpness and will sort of "fade" from sharp to out of focus at some point...

[gryphonslair99]

That "blurred/fuzzy" look is called bokeh. There can be good bokeh and great bokeh. It all depends on the lens you are using. As the previous contributors have advised the DOF you choose to work with creates the bokeh effect.

However the quailty of the bokeh itself is the product of the lens construction. Canon's 50mm f1.8 lens produces nice bokeh, but is a little to patterned. Canons 50mm f1.4 produces smooth great bokeh. This link gives a nice comparison of the two lenses I have mentioned..

http://photo.net/equipment/canon/ef50/

[another view]

Just to clarify, "how much" the background is out of focus has to do with the depth of field. Bokeh has to do with the quality of it, I guess you could say - not the quantity.

I've had lenses that were known for being excellent in this regard and some known for being not-so-good but never looked at one of my images and thought it was ruined because the Bokeh wasn't good. I don't lose sleep over it...

[Medley]

Also, just so you know the option exists, this effect can be simulated with an image editor. Notice that I did not use the word "duplicated". In-camera is still the best way to achieve this effect. But depending on the shutter speed you want (or need) to use, setting the proper aperature for a good DOF while maintaining proper exposure can be downright difficult.
The best way I know to mimic the effect is with the lens blur filter in Photoshop.

-Medley.

[Glen A Ford]

hi, agree with all the previous comments. this effect comes from a low depth of field (subject in focus, background out of focus). to get this effect there are two main variables: (1) the focal length of the lens (e.g. 50mm v 100mm) - a longer focal length will have less depth of field at the same aperture (2) the aperture setting (a large aperture - which is a low f-stop) will have less depth of field. of the two, aperture is the most important.

the key feature when looking for a lens for your new camera is the maximum aperture setting (low f-stop). to get what you are looking for you will need f4 or below and ideally f2 or below. These lens tend to be professional grade, though, so cost a lot of money, especially if you want in zoom as well.

weight is another important aspect as well as cost, as large aperture means a lot of glass, which means heavy and bulky. a prime lens (non-zoom) lens like a 50mm would be a good option, as it is not too heavy, is not too costly. if you get the 50mm f1.4 then this will give you you the effect you are looking for, i suspect, and is a good portrait lens on the 30d.

i've attached a few examples, all using lens with apertures of f2 or below. hope you enjoy your new camera.