DOF ~ revisited...

[sando]

Just a quick one:

I know you've all been over this 18 million times, but please spare 4 seconds of your time to help!

I need a quick reference guide to DOF.

Am I right in thinking that in simple terms:

Small F number means large aperture, and therefore lots of DOF
Large F number means small aperture, and therefore not so much of DOF

Large aperture (and fast shutter) for portraits and macro to bring attention to the subject?

Small aperture (and therefore slow shutter speed) for landscapes to get it all sharp?

Thanks folks!

Matt

[mizuno]

That's somewhat basically and somewhat generally correct.

[Choderboy]

You typed:

"and therefore lots of DOF"

twice. Change one of them and you have it correct.

[sando]

Cheers! Edited the post now!

[Woolburr]

I think you have that backwards.

f/1.4 is a small number, very large aperture and almost no depth of field.
f/22 is a large number, very small aperture and tremendous depth of field.

[saravrose]

I think you have that backwards.

f/1.4 is a small number, very large aperture and almost no depth of field.
f/22 is a large number, very small aperture and tremendous depth of field.

yep.:D

[CyberDyneSystems]

I think you have that backwards.

f/1.4 is a small number, very large aperture and almost no depth of field.
f/22 is a large number, very small aperture and tremendous depth of field.

Ditto

[Crashless]

It frustrates me how backwards the general internet describes DOF. There's a huge amount of mis-information, which makes it even more confusing for people.

If you have 'LOTS' of depth of field, most/all in your frame is in focus. This is a result of a number of variables, but most notably a small aperture (large #, ie: 22), the subject is far away, and the lens is short (ie: 28mm)

IE:

http://www.vinceanido.com/gallery/d/2157-2/IMG_0405.JPG (http://www.vinceanido.com/blog/v/Photography/30in30/IMG_0405.JPG.html)

If you have 'NO/LITTLE' DOF, very little is in focus. You have a large aperture (small #, 1.8 ), the subject is very close to the sensor and your're using a longer lens (ie: 200mm).

IE:

http://www.vinceanido.com/gallery/d/2148-2/IMG_0352a.JPG (http://www.vinceanido.com/blog/v/Photography/30in30/IMG_0352a.JPG.html)

You can click through the images to my site, then click 'detail' on the bottom to see the exif information for these two examples. Hope this helps.