Focus Question.

[icicle]

Can a person use a smaller aperture to focus closer to the lens when you run out of focus adjustment?

I know that when you go smaller you can increase you DOF. and when you go larger you get a shallow DOF.

but does it work in opposite to?
if one has a non macro lens but wants to take a close-up beyond the minimum focus distance of the lens.

lets say if I use a 18-55 mm zoom lens with a minimum focus distance is 9.8 in.
and I want to take a close-up at 5.5 in, will using a smaller aperture like a f/32 do the trick?

[Franglais]

Yes you can use a small aperture to get greater depth of field (shorter focal length will also increase the depth of field but will also change the view).

However even at 18mm f32 a subject at 5.5 inches will be out-of-focus if the lens is focussed at 9.8 inches. Do the calculation for yourself here :

http://www.dofmaster.com/dofjs.html

How about using a close-focussing screw-in filter on the front of your lens? It won't be as good as a macro lens but it might do the job.

[freygr]

Originally Posted by icicle

Can a person use a smaller aperture to focus closer to the lens when you run out of focus adjustment?

I know that when you go smaller you can increase you DOF. and when you go larger you get a shallow DOF.

but does it work in opposite to?
if one has a non macro lens but wants to take a close-up beyond the minimum focus distance of the lens.

lets say if I use a 18-55 mm zoom lens with a minimum focus distance is 9.8 in.
and I want to take a close-up at 5.5 in, will using a smaller aperture like a f/32 do the trick?

This is true, but in micro-photography the distances you are asking is almost a 2X. There isn't a lens with a normal angle of view on any camera I know off which will bring both objects into focus but for a pinhole.

Franglais gave you a link and there is a Palm App also, which is very good DOF Master.

[SmartWombat]

I would use an extension tube, rather than put glass in front of the lens.