Good DOF?

JChurill

What kind of lens / technique is required to get this kind of DOF? I have a Digital Rebel with a 35-70 Sigma lens. Just can't seem to get good DOF with it?

Thanks,

Photo posted by BsrtVW here http://www.dgrin.com/showthread.php?t=127895

http://kadvantage.smugmug.com/photos/515524465_44AM6-L.jpg

(Mod edit to display link to image that is not the property of poster)

JustPlainMe

I looked in his Smugmug Gallery and that photo was taken 1/800 s, f/14, 20mm. The longer the focal length, the more narrow the DOF, but I don't know what lens he used. I have an 18-70, so 20mm would give me just about everything in focus. His aperture was stopped down to f/14, which will also keep a lot more of the area in focus. I know on my 18mm, a 20mm focal length will have everything in focus. I have to move out to 50mm or more to start getting a smaller DOF. But I'm just beginning to understand aperture, DOF, and focal length. I may be completely off base. I'd be interested in seeing a technical explanation from someone in the know.

Try staying at 35mm, and shoot in natural light outside with your aperture stopped down---at least f/11 or f/14 if you can. See what happens.

BobbyMarshall

Here is a link to a DOF chart.
http://www.dofmaster.com/doftable.html

input the focal length, select camera from dropdown, etc.

On the left of the chart where is says Distance, it is your distance to the subject of primary focus.

the other numbers as you go across are the min/max distance of sharpness for each of the f-stops.

if you play around with different focal lengths you will be able to see what is happening. shorter lengths will have a wider range of distance of what is sharp. and also a shorter focal length lens will reach their hyperfocal distance at a shorter range (where everything beyond that point is within acceptable focus).


The chart linked above is quick and handy, but here is another link that descries depth of field pretty well.
http://www.cambridgeincolour.com/tutorials/depth-of-field.htm

JChurill

Thanks Bobby I've done some Googling reg DoF but that link you gave is just what I needed! Thanks