Maximum Depth of Field and Sharpness


jreamer

New Member
Dec 3, 2009
98
0
0
#1
Hi guys,

I have been doing some reading in my free time and recently I saw this magazine article about hyperfocal distances. It was really useful as I will be going on a USA trip soon and expect to take a lot of landscape photos especially with my people inside them so maximum depth of field is critical.

At 17mm with a crop sensor and f11 aperture, the hyperfocal distance seems to be 4.5 ft = 1.37m, which seems strangely near. So lets say I'm taking a photo of the grand canyons, do I tilt my camera to focus on the ground 1.37m in front of me and then tilt the camera back up to take the shot? I can't seem to grasp this technique.

As a shortcut there was mention of a shortcut by focusing 1/3 into the scene. Again, I can't seem to grasp what this really means especially if you consider a strong foreground like when you go very low on the ground for a photo. 1/3 of distance the distance from where you are to the far away mountains or trees is not the same as the distance to a point at 1/3 of the photo composition if you know what I mean. So do they really mean 1/3 of the distance from me to the faraway mountains or trees? Or at a point located somewhere at 1/3 of the photo composition?

Any help in this matter would be greatly appreciated.
 

catchlights

Moderator
Staff member
Sep 27, 2004
21,903
46
48
Punggol, Singapore
www.foto-u.com
#2
I suggest you re read the Depth of Field Calculator carefully again.

for a Canon 1000D or 600D camera with 17mm lens, focusing on a subject at 5ft,


Subject distance 5 ft

Depth of field
Near limit 2.36 ft
Far limit Infinity
Total Infinite

In front of subject 2.6 ft
Behind subject Infinite

Hyperfocal distance 4.47 ft
Circle of confusion 0.019 mm


your subject at 5 ft is in focus, and anything at 2.6ft or at the infinity is reasonably sharp.
 

ziploc

New Member
Jan 17, 2002
4,576
0
0
Snoopyland
#3
And if you're using an iPhone/Android, there are free apps available from app store/android market that calculates the DOF and hyperfocusing distance, so no need to use the 1/3 guesstimation. :)
 

ziploc

New Member
Jan 17, 2002
4,576
0
0
Snoopyland
#4
Oh and for the other part of your question: there should be a focus distance indicator on your lens which you can use to help getting the right distance. So using the example that uncle catchlight gave above, one way is like you mentioned - 1st find an object that is about 5ft away, focus on it and lock focus, then recompose and take the shoot. But the simpler way is just switch to manual focus, turn the focusing ring till the distance indicator is 5ft, then compose and shoot. Note that the background might look blur (unless you press the DOF preview) as the aperture is wide open during composition/metering and will only close down when the shutter is released.
 

Last edited:

jreamer

New Member
Dec 3, 2009
98
0
0
#5
thanks for your kind replies.

I was initially confused because for f11, the hyperfocal distance is merely 1.37m. I had the wrong impression that I had to focus at that distance even if there are no subjects within that distance to get maximum depth of field (silly me?).

In any case, I'm clearer about what I should be doing now. Correct me if I'm wrong but if the subjects of the landscape concerned are all further than the hyperfocal distance, I just need focus on the nearest subject and the subject in focus to everything else to infinity will be in focus? i.e. if someone is standing at 4m and the hyperfocal distance is 1.37m, I just need to focus on that someone who is standing at 4m and everything from that person to infinity will be sharp and in focus.
 

Last edited:

daredevil123

Moderator
Staff member
Oct 25, 2005
21,662
68
48
lil red dot
#6
jreamer said:
thanks for your kind replies.

I was initially confused because for f11, the hyperfocal distance is merely 1.37m. I had the wrong impression that I had to focus at that distance even if there are no subjects within that distance to get maximum depth of field (silly me?).

In any case, I'm clearer about what I should be doing now. Correct me if I'm wrong but if the subjects of the landscape concerned are all further than the hyperfocal distance, I just need focus on the nearest subject and the subject in focus to everything else to infinity will be in focus? i.e. if someone is standing at 4m and the hyperfocal distance is 1.37m, I just need to focus on that someone who is standing at 4m and everything from that person to infinity will be sharp and in focus.
I've written a write up with examples that answers your questions. Maybe you want to check it out.
http://darthbertz.blogspot.com/2010/07/getting-everything-into-focus.html

Hope it helps.
 

jreamer

New Member
Dec 3, 2009
98
0
0
#7
Thank you, dd123. The article was most useful. The following excerpt answered my burning questions:

"What if I do not have a distance scale on my lens, and/or I do not know whether I can focus at the exact spot?

Do not worry. Hyperfocal distance will work further away. So if you are not sure, just focus on a spot further away than the calculated hyperfocal distance, and everything from at least half of the distance of that spot to infinity will be in focus."

I guess its easy to get most things in a landscape to be focus with f8-11 and a short focal length because the hyperfocal distance tends to be short (approx 1+ to 2 metres). Just have to avoid focusing too far away.

Thanks again!
 

Last edited:

daredevil123

Moderator
Staff member
Oct 25, 2005
21,662
68
48
lil red dot
#11
thelight said:
learnt alot from this link too.
thanx DD123,
U DA MAN!!
I am a normal man. Glad you find it useful. Just passing on what I've learnt. No big deal. ;)
 

#12
very good artical dd123!

i would like to try this in my landscape shots.

unfortunately my kit lens does not have the scale on focusing distance.

guess i have to try out myself.

lol
 

Top Bottom