aperture question

[swmocity]

That sounds like it could be it. The low F-stop does give you a shallow DOF, but that DOF is still wherever you focus, so if the photographer focused on the people, they would be in focus, but anything behind them and infront of them would be out of focus. The further in the foreground and further in the background you go, the more out of focus the image will become with any F-stop. The severity of the blurred back and foreground is just dramatically increased with a low F-stop.

Hope that makes sense.
Mark

yes one more question...so basically its like a "focus circle" i guess?...does the DOF start out in the middle then expands out in a circular pattern...hopes that make since...its kind of hard to explain lol

I wouldnt call it a circle, more of a plane I think. If you were to look at a pool table from standing position and focus on the middle at F/8, you would only get about a quarter of the table in focus, but the floor and ceiling to the left, right, top, and bottom, of the plane would be in focus too, just not outside of that plane.

If you were to take the same pool table, but look at it from above straight down with an aperture of F/8, since the pool table top is flat, the whole 8' (or as much of it that can be in frame) would be in focus, but the ground under the table wouldnt be because its not in the verticle plane of focus.

The plane is always straight up and down, left and right. The only thing that changes is the thickness and that is with a change in the aperture (F-stop). Larger numbers, the thicker the plane. Smaller numbers, the thinner the plane. So its nore like a verticle square than a horizontal circle, if that makes sense.

Mark

ahhh ok ok i see what your saying...thx alot...and that bug picture helped also

 

[Markw]

No problem, I thought I would confuse you more than anything with my psycho-babble Glad to help.

Mark