Question about DOF again...

Holly · Dec 13, 2005

I read and understood what DOF is.. however, Im clueless on how to GET this??? I have tried taking pictures and dont see a bloggy blur background.. Curious to know how to do this? Maybe my camera doesnt have this feature? OR It does and I dont know what it is..?

Thanks

photoboy15 · Dec 13, 2005

What camera? And what is the largest apature?

Big Mike · Dec 13, 2005

DOF is a result of aperture, focal length and distance to subject. (I think that's it). To get shallow DOF (subject with out of focus BG), set the aperture as wide as possible (low number), zoom out or use a long focal length and get close to your subject.

You might be limited by your equipment. You just won't be able to get a very shallow DOF with a small sensor digi-cam...like you could with a 35mm SLR with an F1.4 lens.

cecilc · Dec 13, 2005

Holly said:
I read and understood what DOF is..

Somehow .... I don't think you do just yet ....

DOF is not something that you GET .... DOF just IS ....

DOF is the acceptable range of focus in front of and behind the subject that you're shooting .... and it's not something that you have to practice; hope for; or buy ..... it's just there ...

Now, the other issue you spoke of - the "bloggy, blurry background" is another matter. That's affected by several things: distance of the subject from you; distance of the subject from the background; the aperture that you're shooting at ... etc.

Usually that "bloggy, blurry background" is achieved with a large aperture - 2.8 or lower. The larger the aperture, the shallower the DOF and more prounounced is the blur of the out of focus stuff.

Holly · Dec 13, 2005

SO If this focal object is closer to me... my Apeture setting is 2.8 chances are my background will be bloggy (AT any time OR Only if the background is a bit further away)? Yes 2.8 is my lowest.. My highest is 11

I Think I am getting this now.. Will practice with it and get pictures up for thoughts and help on the turn around

Thanks!!

Rob · Dec 13, 2005

Yep, sounds like you've got it Holly.

The smaller the f-number and the greater the distances involved, the more blur. A picture of a friend six feet away at f2.8 with mountains in the background will have a very blurry background, whereas a picture of one mountain with other mountains further in the background at f22 is likely to be all in focus.

Rob

cecilc · Dec 13, 2005

Holly said:
SO If this focal object is closer to me... my Apeture setting is 2.8 chances are my background will be bloggy (AT any time OR Only if the background is a bit further away)?

Holly, anything that is outside the DOF will not be in focus .....

For instance, with my MKII and a 200 2.8 lens, if I shoot something that's 50 feet away from me at 2.8 then the acceptable "range" of focus (or DOF) is going to be about 2.5 feet. Everything in that 2.5 foot range will be in focus - anything that's not in that range will be out of focus (both in front of and behind my subject). Now if my subject is standing against a wall, chances are that the wall will be in that 2.5 foot of DOF and will still be in focus. However, move the subject 10 feet in front of that wall and the wall gets blurred because it's no longer in that 2.5 foot range of focus.

Now, you move that subject to 10 feet from you and the DOF decreases to less than a foot of acceptable focus range.

DOF will change as the focal length of your lens changes; the distance of the subject from you changes; and/or your aperture changes.