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Great detail. I love B&W.
Not sure what type of lens, but if it has a depth of field chart on it, you can determine how much will be in focus.
Unfortunately I know next to nothing about cameras, it's a Rebel XTI is all I know haha but I'm learning as I go along. I can figure out the required distance for things to be in focus, but not much else haha
The Depth of Field is determined by Subject Distance, Aperture and Focal Length.
Increasing FL results in decreased DOF.
Conversely, Reducing A results in greater DOF.
Focus exists at a theoretical point in space and it's plane is parallel to the film (sensor) plane.
(lenses and cameras exist that allow for non-parallel adjustment of the lens board and film plane.)
However, the area within a "circle of confusion" is perceived as in focus.
DOF and critical focus can be determined mathematically by formulae and established by physical measurement.
This is done frequently in motion picture cinematography and macro photography.
In a SLR, one can simply preview through the lens to visualize DOF.
Most 35mm SLR's have an aperture preview setting that looks through the selected aperture rather than a wide open one (the default for the viewfinder).
Some DSLR's have this feature too. Use it if you have it.
The rule of thumb is that
DOF extends 1/3 in front of the focal plane and 2/3's behind it.
Barring the math, that is your take-home lesson.