Am I Correct In Thinking....

[ColoradoBrit]

That if I focus on a background subject and get it in focus, and then re-set my framing that both background and foreground should be in focus? (Assuming that i am using a long apperture)?

I am sure that i read somewhere?........................

[autofocus]

Originally Posted by ColoradoBrit

That if I focus on a background subject and get it in focus, and then re-set my framing that both background and foreground should be in focus? (Assuming that i am using a long apperture)?

I am sure that i read somewhere?........................

The range of acceptable focus is 1/3 in front of the focus point and 2/3 behind the focus point. That being the case, I'd have to believe that focusing on the foreground subject will give you a better chance of acceptable focus on the background subject.

[BryanC]

Originally Posted by ColoradoBrit

That if I focus on a background subject and get it in focus, and then re-set my framing that both background and foreground should be in focus? (Assuming that i am using a long apperture)?

I am sure that i read somewhere?........................

There are variables that come into play: Aperture, focal length, distance from subjects, distance between subjects,...Do a search on Depth of Field and Hyperfocal Distance. There's been good information posted on DPS and on the net in general. Here's an online DOF calculator that should get you going in the right direction:

Online Depth of Field Calculator

[danbaileyphoto]

As long as you don't move your camera forward or back, the background subject that you focused on should remain in focus. However, that doesn't mean that your foreground will be sharp, even if you stop the lens all the way down.

You'll have to check the lens barrel to see the focus distances, if your lens even has such a thing, use the depth of field preview button, which you may not have, or consult a depth of field chart. And as BryanC said, there are many variables that come in to play- lens length, maximum aperture, distance to and between subjects...

[cray101]

If you have an adequately small aperture you will be able to focus on objects at different distances from the lens. 'Adequate' though varies from lens to lens. But it does not matter whether you focus on the backgrond or foreground as long as your DoF range accommodates both their distances.