Focusing "a third of the way in" - how?

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When doing landscape photography, one is often advised by magazines to focus " a third of the way in", but what do they mean?

Eg if I have a landscape which has a rock ten feet away, a tree a hundred yards away and a mountain six miles away ( I estimate) and I want them all to be in focus. So that's a distance of six miles to cover. I set the camera to f/18 or F/22 and manually focus on - what? Is it whatever happens to be two miles away (one third of the way in)? How can you tell if this is sharp or not at that distance? I can't really tell from my 5D's little screen even if I take a test shot and zoom in for a look.

Is hyperfocal distance focusing the only real way to be sure?
 
The idea is that roughly one third of the acceptable sharpness is in front of the point of focus and the other two thirds behind.
In practice hyperfocal should give your the most in focus, in practice I'd want the rock and tree sharp and not so worried about the mountain.
It's also worth considering that at very small apetures (f16-22) difraction starts to soften the image slightly, but how much depends on lens and sensor size.
 
Rooster said:
When doing landscape photography, one is often advised by magazines to focus " a third of the way in", but what do they mean?

Eg if I have a landscape which has a rock ten feet away, a tree a hundred yards away and a mountain six miles away ( I estimate) and I want them all to be in focus. So that's a distance of six miles to cover. I set the camera to f/18 or F/22 and manually focus on - what? Is it whatever happens to be two miles away (one third of the way in)? How can you tell if this is sharp or not at that distance? I can't really tell from my 5D's little screen even if I take a test shot and zoom in for a look.

Is hyperfocal distance focusing the only real way to be sure?
Click to expand...

"Focus a third in" is just another easy to remember guide, like "sunny 16".

I'm guessing you usually use only one or two lenses for most landscapes you shoot.. I know that's the case with my kit bag. I printed up a DoF table for each lens and stuck it in a pocket of my bag.
 
Similar comment when it comes to hyperfocal distance. It's great to understand the theory, but applying it in the field is a different matter. Experimentation is the key, and I'd stick away from aperatures smaller than f16 unless you really need them. Just as a test, when shooting fairly wide (say 18mm on a crop sensor) focus around 10 meters in front of you and set the camera to about f10. You'll find that you have acceptable focus to infintity for most applications.

Shooting at unneccesarily small aperatures was the biggest mistake which I made when starting out.
 
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RichieRich said:
The 1/3 rule is rather misleading and not that useful in my opinion - after all, how do you really focus 1/3 of the way into a scene accurately?

It's also worth remembering that the 1/3 depth of field rule only applies to wide focal lengths.

This is a great summary:

http://www.cambridgeincolour.com/tutorials/depth-of-field.htm
Click to expand...

Errr no it doesn't, all lens have around 1 third of the acceptable area of focus before the plane of focus and roughly 2 thirds after.
The amount that is acceptable will vary with focal length and apeture though. You will get more depth of field so more in focus with a wide angle lens, but the 1/3 - 2/3 bit still applies.
 
swanseamale47 said:
Errr no it doesn't, all lens have around 1 third of the acceptable area of focus before the plane of focus and roughly 2 thirds after.
The amount that is acceptable will vary with focal length and apeture though. You will get more depth of field so more in focus with a wide angle lens, but the 1/3 - 2/3 bit still applies.
Click to expand...

Sorry but you're wrong there swanseamale. Once you get to about 50mm the ratio is roughly 50/50. Check the table in the link which I posted. The longer the focal length the closer the value tends towards 50%.
 
Thats not taking into account that the forground detail is usually more important than background detail and differs from the complicated maths in my ilford manual of photography, which states what I said above. Although at very close flcus it does get closer to 50/50
 
Think I'll just stick with making sure the foreground is sharp and let the rest take care of itself. Thing is, I'm starting to prefer the 70-200mm for landscapes rather than a wide lens and the more I zoom in the less depth of field I will get. I suppose that's why it goes up to f/32.
 
Think I'll just stick with making sure the foreground is sharp and let the rest take care of itself
Click to expand...

I would try and master the Hyperfocal Distance if i was you because the results will be rewarding. This is an area that I am still mastering and will keep going until I perfect it.

The theory side, I understand, its putting it all together in the field that gets my underpants in a twist.

Take yesterday for example, I went out to a place called Lady Bower Reservoir http://www.talkphotography.co.uk/forums/showthread.php?p=3244418#post3244418 according to my thermometer, it was -4 / -5 degrees where I was stood and I was freezing. To concentrate on composition, working from a HP chart and battling with the cold was challenging and in the end I retired and put the heater on in the car.

Here is a very good tutorial on Hyperfocal distance which does explain it rather well

http://photo.tutsplus.com/tutorials...imum-depth-of-field-in-landscape-photography/
 
NigelPaul said:
Read Hoppy UK's input on this thread, it may help?
http://www.talkphotography.co.uk/forums/showthread.php?t=255258
Click to expand...

There's a lot in that thread, and some other recent ones.

Basically, you shouldn't use 'one third-in' for landscapes where you want the far distance to be sharp. Even if it was possible (what's one third of infinity?) you would lose out on a lot of foreground sharpness. You need hyperfocal distance focusing for that.

The one third-in rule works for general scenes at normal range, like groups for example. You need to have a fixed near point and far point for the depth of field needed, and then focus one third into that zone. For example, if you want everything sharp from 3m to 6m, then if you focus on 4m you will maximise the DoF either side.

The third-in rule is very approximate. At very close distance like macro, DoF is very close to 50:50 either side of the focus point, and with hyperfocal distance setting there can be many thousands of times more DoF behind than in front.

This is a good on-line calculator and great source of DoF info www.dofmaster.com
 
As usual whenever there's a thread about DOF and hyperfocal distances, there's a lot of disinformation here.

RichieRich said:
It's also worth remembering that the 1/3 depth of field rule only applies to wide focal lengths.
Click to expand...
Not true.

swanseamale47 said:
Errr no it doesn't, all lens have around 1 third of the acceptable area of focus before the plane of focus and roughly 2 thirds after.
Click to expand...
Not true.

RichieRich said:
Sorry but you're wrong there swanseamale. Once you get to about 50mm the ratio is roughly 50/50. Check the table in the link which I posted. The longer the focal length the closer the value tends towards 50%.
Click to expand...
Not true.

HoppyUK said:
The one third-in rule works for general scenes at normal range, like groups for example. You need to have a fixed near point and far point for the depth of field needed, and then focus one third into that zone. For example, if you want everything sharp from 3m to 6m, then if you focus on 4m you will maximise the DoF either side.
Click to expand...
True in some cases, but not reliably so.

HoppyUK said:
The third-in rule is very approximate. At very close distance like macro, DoF is very close to 50:50 either side of the focus point, and with hyperfocal distance setting there can be many thousands of times more DoF behind than in front.
Click to expand...
Absolutely!

This notion of the DOF extending 1/3 in front and 2/3 behind is simply rubbish, but that doesn't stop it being peddled around as if it were the gospel truth.

A while ago I had a slow day in the office so I did some calculations. (Well actually DOFMaster did.) Suppose you have a 55mm lens on a 350D at f/8. The hyperfocal distance is 20m. With the subject at various distances, the DOF is as follows:

* Subject at 1m: DOF from 0.95m to 1.05m (48% in front)
* Subject at 2m: DOF from 1.82m to 2.22m (45% in front)
* Subject at 3m: DOF from 2.61m to 3.52m (43% in front)
* Subject at 5m: DOF from 4m to 6.65m (38% in front)
* Subject at 6.67m: DOF from 5m to 10m (33% in front)
* Subject at 10m: DOF from 6.67m to 20m (25% in front)
* Subject at 15m: DOF from 8.57m to 60.2m (12% in front)
* Subject at 19m: DOF from 9.73m to 395.4m (2% in front)
* Subject at 20m: DOF from 10m to infinity (0% in front)

Note that there is only one point at which the DOF is 1/3 in front of the subject and 2/3 behind the subject, and that is when the subject is at exactly 1/3 of the hyperfocal distance.

This is true for all lenses, at all apertures. The 1/3 - 2/3 rule only applies when the subject is at exactly 1/3 of the hyperfocal distance.
 
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ianbarber said:
I would try and master the Hyperfocal Distance if i was you because the results will be rewarding.
Click to expand...
Hmmm. I'm not so sure.

I think the notion of of hyperfocal focussing is better in theory than in practice. Yes, the idea is, of course, the you get the maximum DOF. But what that means is that the far distance is, by definition, right on the limit of acceptable sharpness. And that word "acceptable" contains all sorts of hidden assumptions, which may not be valid for your particular situation. If you have details in the far distance which you want to ensure are sharp (eg a range of mountains) then it is safer to ensure that your focus is considerably beyond the hyperfocal distance.
 
Getting back to the original "Focusing "a third of the way in" - how?

1 Establish position on map
2 Determine position of most distant object in the scene.
3 Use scale on map to fix 1/3 position
4 Set SatNav and drive to said location and erect Black & White surveyors pole.
5 Set Sat Nav and return to original location
6 Focus on Pole
7 Take photo
8 Return to 1/3 site to collect pole.
9 Check shots on PC on returning home.
10 Repeat from 1 if incorrect exposure.

Simples :D
 
artyman said:
Getting back to the original "Focusing "a third of the way in" - how?

1 Establish position on map
2 Determine position of most distant object in the scene.
3 Use scale on map to fix 1/3 position
4 Set SatNav and drive to said location and erect Black & White surveyors pole.
5 Set Sat Nav and return to original location
6 Focus on Pole
7 Take photo
8 Return to 1/3 site to collect pole.
9 Check shots on PC on returning home.
10 Repeat from 1 if incorrect exposure.

Simples :D
Click to expand...


:clap::clap:
 
artyman said:
Getting back to the original "Focusing "a third of the way in" - how?

1 Establish position on map
2 Determine position of most distant object in the scene.
3 Use scale on map to fix 1/3 position
4 Set SatNav and drive to said location and erect Black & White surveyors pole.
5 Set Sat Nav and return to original location
6 Focus on Pole
7 Take photo
8 Return to 1/3 site to collect pole.
9 Check shots on PC on returning home.
10 Repeat from 1 if incorrect exposure.

Simples :D
Click to expand...

11 Remember to clone out black and white surveyor's pole from photo
 
HoppyUK said:
There's a lot in that thread, and some other recent ones.

Basically, you shouldn't use 'one third-in' for landscapes where you want the far distance to be sharp. Even if it was possible (what's one third of infinity?) you would lose out on a lot of foreground sharpness. You need hyperfocal distance focusing for that.

The one third-in rule works for general scenes at normal range, like groups for example. You need to have a fixed near point and far point for the depth of field needed, and then focus one third into that zone. For example, if you want everything sharp from 3m to 6m, then if you focus on 4m you will maximise the DoF either side.

The third-in rule is very approximate. At very close distance like macro, DoF is very close to 50:50 either side of the focus point, and with hyperfocal distance setting there can be many thousands of times more DoF behind than in front.

This is a good on-line calculator and great source of DoF info www.dofmaster.com
Click to expand...

DOF Master seems good, even though it's only got the 5D mark II on there, maybe my Mark I is the same. Can anyone recommend an iphone app that does the same thing? I expect there's loads.
 
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Rooster said:
DOF Master seems good, even though it's only got the 5D mark II on there, maybe my Mark I is the same. Can anyone recommend an iphone app that does the same thing? I expect there's loads.
Click to expand...

The camera model doesn't matter particularly, it's just a handy reference to the sensor format and it changes the size of the circle of confusion in the formula.

5D2 will be the same as the 5D1, or Nikon D700, D3 etc - ie full frame.
 
StewartR said:
As usual whenever there's a thread about DOF and hyperfocal distances, there's a lot of disinformation here.


Not true.


Not true.


Not true.


True in some cases, but not reliably so.


Absolutely!

This notion of the DOF extending 1/3 in front and 2/3 behind is simply rubbish, but that doesn't stop it being peddled around as if it were the gospel truth.

A while ago I had a slow day in the office so I did some calculations. (Well actually DOFMaster did.) Suppose you have a 55mm lens on a 350D at f/8. The hyperfocal distance is 20m. With the subject at various distances, the DOF is as follows:

* Subject at 1m: DOF from 0.95m to 1.05m (48% in front)
* Subject at 2m: DOF from 1.82m to 2.22m (45% in front)
* Subject at 3m: DOF from 2.61m to 3.52m (43% in front)
* Subject at 5m: DOF from 4m to 6.65m (38% in front)
* Subject at 6.67m: DOF from 5m to 10m (33% in front)
* Subject at 10m: DOF from 6.67m to 20m (25% in front)
* Subject at 15m: DOF from 8.57m to 60.2m (12% in front)
* Subject at 19m: DOF from 9.73m to 395.4m (2% in front)
* Subject at 20m: DOF from 10m to infinity (0% in front)

Note that there is only one point at which the DOF is 1/3 in front of the subject and 2/3 behind the subject, and that is when the subject is at exactly 1/3 of the hyperfocal distance.

This is true for all lenses, at all apertures. The 1/3 - 2/3 rule only applies when the subject is at exactly 1/3 of the hyperfocal distance.
Click to expand...

You believe what you want and I'll believe the maths.
 
My brain is on the huhh after reading this :lol:
No dis-respect to anyone here, cos I find many good contributers on this thread, but IMHO, and I and hope the OP will agree to, go with what Hoppy Uk says, Don't think you can go far wrong!
 
StewartR said:
Glad we're in agreement then. Cheers!
Click to expand...

Seems to me you are in agreement! Those are the numbers. And they are mostly around one third.

If you look at the cluster of them, they are all around one third, and if you average them all out, they come to 27% which is as close to one third as you can realistically achieve in practise. Depth of field is only an exact science in theory - in practise, exactly where 'sharp' begins and ends is far from precise when you look at an image.

I think that if you remember than the 'one third in' rule only applies to 'normal range' pictures and that it is different when close up and quite a lot different with distant landscape scenes (when you should use hyperfocal distance technique) then in the absence of better information, it's quite handy to know.

Edit: this is what I've got inside my lenscaps - tells me pretty much everything I need to know. I use those numbers (they're for full frame) in conjunction with the HFD technique outline in the post linked by NigelP at the top of this thread.

IMG_4014-1.jpg
 
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Hyperfocal distance is only the point where you get the greatest range of acceptable focus, you may want to focus slightly closer to improve nearer objects at the xpense of the far distance ones, as most people accept really far distance is going to be less distinct as naturally observed with the Mk1 eyeball.
 
Even in broad landscapes, there's often a major point of interest, maybe an interesting shaped tree or similar. Use that as the point of sharpest focus and an aperture small enough to get you enough DoF without running into diffraction softness.
 
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