Good way to visualise a 1/3 of a way into an image..?

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BertieTBE

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Hi all,

I'm working on improving my landscape shots. I've been reading 'From Snapshots to Great Shots', which recommends focusing 'a 1/3 of the way into the image' to get a decent level of sharpness through to infinity.

I understand the basic concept of Hyper Focal Distance (HFD). But I'm having difficulty visualising what 'a 1/3 of the way into the image' actually means. Maths is not my strong point (to say the least!) so I find it hard to imagine what a 1/3 means in visual terms.

I'd be SO grateful if you could help me get my head round this with as few numbers as possible:)

Do we mean - a 1/3 of the distance (metres / ft) from the camera to infinity? Or a 1/3 of the way across the frame?

What happens when there isn't any clear focus point between you and infinity (e.g. when the only think between you and the horizon is the sea - no rocks?)

Sorry if this is a silly question. As I said, fractions are a foreign language to me! :)

Many thanks.

BertieTBE
 
Hi, For a quick solution there are two options I use, look through the view finder and guess along about third of the way from the bottom of the finder and pick something to focus on along that line or the easier way if you have the in camera option of showing the grid in the view finder or live view use the lower line of the grid and focus on something along that line.
Of course mostly done on tripod and focus in manual on the point you choose, around F8 to F16 will give you a good focus across the scene IMO.
Russ
 
As I'm sure you're aware, the horizon isn't at infinity, it depends on your height above sea level as to the actual distance. ( http://www.ringbell.co.uk/info/hdist.htm ) I usually do the same as Russell but I use auto focus on the area that a rough guess is 1/3rd of the way in then recompose. If tripod mounted, I'll manually select a different AF point (I usually use the central one but do vary from there for tripod mounted landscapes) that lands on the area I want to use as the focus point. For handheld seascapes, I tend to leave the AF point as the central one and set the horizon on the top 1/3rd line or just have the horizon running through the centre of the frame and focus on that. There's usually some sort of foreground interest though, so I try to make sure that's in reasonable focus.
 
Don't worry about "focussing 1/3 of the way into the image". It's an old wives' tale based on an inadequate understanding of the maths of Depth of Field (DOF).

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 Canon 350D at f/8 (which is what I had in my hand at the time). 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)

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.

Note also that the maximum DOF is achieved when the subject is at the hyperfocal distance.

These two conclusions are not dependent on the choice of camera, lens, focal length, aperture or subject distance.

My recommendation: focus at the hyperfocal distance or just beyond. The trouble with hyperfocal focussing is that, by definition, objects at infinity are right on the limit of acceptable sharpness. However, "acceptable" is a somewhat flexible term and what's acceptably sharp on a computer monitor might not be acceptably sharp on a 36"x24" print. So if there are objects in the scene "at infinity" (i.e. a long way away), then it's probably safest to err on the side of caution by focussing on a point slightly beyond the hyperfocal distance.
 
BertieTBE said:
Hi all,

I'm working on improving my landscape shots. I've been reading 'From Snapshots to Great Shots', which recommends focusing 'a 1/3 of the way into the image' to get a decent level of sharpness through to infinity.

I understand the basic concept of Hyper Focal Distance (HFD). But I'm having difficulty visualising what 'a 1/3 of the way into the image' actually means. Maths is not my strong point (to say the least!) so I find it hard to imagine what a 1/3 means in visual terms.

I'd be SO grateful if you could help me get my head round this with as few numbers as possible:)

Do we mean - a 1/3 of the distance (metres / ft) from the camera to infinity? Or a 1/3 of the way across the frame?

What happens when there isn't any clear focus point between you and infinity (e.g. when the only think between you and the horizon is the sea - no rocks?)

Sorry if this is a silly question. As I said, fractions are a foreign language to me! :)

Many thanks.

BertieTBE
Click to expand...

Good questions, but no good answers because the 'third into the image' idea that often comes up in questions like this, simply doesn't work with landscapes. What's a third of infinity anyway?

Hyperfocal distance focusing is the best way to maximise depth of field in landscapes, though that too is not perfect. If you set the hyperfocal distance (using the DoF Master link Stewart gave) and then compare it to any interpretation of a 'third into the image' or a 'third up the frame' you'll get some quite different distances, usually resulting in a loss of potential sharpness at closer range.

Easy way to set hyperfocal distance, based on the fact that HFD is always exactly double the distance to the nearest subject needed to be sharp. You need a few HFD reference numbers, like those I have stuck inside my lens cap (in blue, though they only apply to full-frame BTW). You can guess the intermediate settings accurately enough.

Select the nearest foreground subject you want sharp, say it is 6ft away. Now double that distance by eye, ie 12ft, and using a single AF point, focus on something at that distance. That is HFD set.

Then refer to the scale, and at the focal length you're using, select the aperture. Eg, with 24mm lens, that's f/5.6 near enough. Job done.

NB In photographic terms, the actual distance to infinity varies a lot, from the end of the garden with a wide-angle to several hundred yards with a super-telephoto. For this reason, it is only practical to use HFD technique with wide-angles.

 
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Thank you all very much for your detailed and informative replies.

I feel a lot clearer on this now. Will go out and give it a try.

Interesting to get a range of views of HFD. As I'm just starting out, I'm going to go with the simplest method first and take it from there.

Thanks again.
 
In the olden days the Fstop markers on the focus window or scale made hyperfocal focusing very easy.

It also allowed you to tweak a bit toward fore or background depending on composition.
 
Hoppyuk I am loving the DOF guide in your lens cap:clap:
 
StewartR said:
Don't worry about "focussing 1/3 of the way into the image".
Click to expand...

I agree.

There are DoF tables to check or you can use the Merklinger method or you can simply focus on something. Focusing on something and deliberately not going for front to back DoF is IMO a perfectly valid decision.

Landscape = wide angle and front to back DoF seems to be a cliche, I don't agree with.

If you simply must go for front to back DoF I think that focusing 1/3 into the scene is possibly the way to get the most unsatisfactory result.
 
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russellsnr said:
Hi, For a quick solution there are two options I use, look through the view finder and guess along about third of the way from the bottom of the finder and pick something to focus on along that line or the easier way if you have the in camera option of showing the grid in the view finder or live view use the lower line of the grid and focus on something along that line.
Of course mostly done on tripod and focus in manual on the point you choose, around F8 to F16 will give you a good focus across the scene IMO.
Russ
Click to expand...

Went out and tried this today. Reviewing the images, I really can't see any major difference in the depth of field between them.

I must be doing something wrong??

When I press the depth of field preview button that doesn't see to be much help either:|
 
HoppyUK said:
You need a few HFD reference numbers, like those I have stuck inside my lens cap (in blue, though they only apply to full-frame BTW). You can guess the intermediate settings accurately enough./QUOTE]

Does this mean I can't use these for my camera? I've got a Canon 600D and Sigma 18-250.

Isn't it also effected by the focal length your shooting at?

I'm confused now!:shrug:
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The thing that's confusing me is how you start off doing this.

1. Set up your shot (tripod in place, you've decided how you are going to compose it, and you've identified a good focus point (HFD).

2. What comes next?? Aperture?

Be great if someone could summarise the process and the order you'd do it in.

Thank you very much.
 
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BertieTBE said:
The thing that's confusing me is how you start off doing this.

1. Set up your shot (tripod in place, you've decided how you are going to compose it, and you've identified a good focus point (HFD).

2. What comes next?? Aperture?
Click to expand...

You can't HFD unless you know your aperture already, which you decide upon by how much DOF you want and how much movement you want in your image. (y)
 
BertieTBE Does this mean I can't use these for my camera? I've got a Canon 600D and Sigma 18-250.
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Go to the DoF Master site (as linked by Stewart) and draw up your own table for your camera format. For your lens, suggest 18mm, 24mm, 28mm and 35mm, at f/4, f/8, and f/16.

Isn't it also effected by the focal length your shooting at?
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Yes, of course.

I'm confused now!:shrug:
Click to expand...

This is not difficult! Re-read post #6 - it's all there.


BertieTBE said:
The thing that's confusing me is how you start off doing this.

1. Set up your shot (tripod in place, you've decided how you are going to compose it, and you've identified a good focus point (HFD).

2. What comes next?? Aperture?

Be great if someone could summarise the process and the order you'd do it in.

Thank you very much.
Click to expand...

I did - post #6.
 
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@ BertieTBE

You are reading too much into it.
Normally for scapes I will be shooting around F8-F11 (Mainly because I will have resonable DOF, focal length dependant, and the sensor dust spots don't show up so much).
If I am specifically going to shoot scapes I will usually have a faily wde angle lens on (12-24 for a 1.6 crop camera) With that you usually have Lots of DOF even at 24mm it is from about 6' to infinty (Most of my images are displayed on a screen or 10x8 prints maximum)

If I can I will shoot at minimum ISO (to reduce noise).
Shutter speed will depend on what I am trying to achieve.

Example #1.
Pre dawn lighting (sunrise will be more or less off to my right). I was using a tripod+remote and 3 stop soft ND grad (to control the sky). I wanted to show water movement and not freeze everyting.
Focused on the near cliff edge (foreground) which was about 12 feet away or so.


The photographer by dicktay2000, on Flickr

Camera Canon EOS 40D + Tokina 12-24mm lens @ 17mm
Exposure 0.5. Aperture f/8.0, ISO Speed 100, Exposure Program Manual
 
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HoppyUK said:
Go to the DoF Master site (as linked by Stewart) and draw up your own table for your camera format. For your lens, suggest 18mm, 24mm, 28mm and 35mm, at f/4, f/8, and f/16.
Click to expand...

That's great, thank you very much.

I've followed the link and as you suggested - fine until I get to 'subject distance'.

Lets take this shot as an example. I think I focused on the rock-face on the right about half way down and then recomposed the shot to get the background (I didn't set the HFD - took this before I got on to this).

https://www.dropbox.com/s/p8l4dksixkmmc1s/Exmoor Landscape -1.jpg

HoppyUK said:
Select the nearest foreground subject you want sharp, say it is 6ft away. Now double that distance by eye, ie 12ft, and using a single AF point, focus on something at that distance. That is HFD set.
Click to expand...

Ok so in this case it's the nearest cliffs on the right. So I'd start by estimating that distance by eye. Then I'd focus on something at double that distance?

So which is the 'subject distance'? The distance to the cliffs on the horizon? Or the distance to the cliffs on the right (my initial focus point)?
 
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Alan Clogwyn said:
You can't HFD unless you know your aperture already, which you decide upon by how much DOF you want and how much movement you want in your image. (y)
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Thanks Alan, that's great.

Are you suggesting being able to decide which aperture to choose to get the desired DOF just comes with experience ?? And when you first start out, a bit of trial and error - shoot and have a look?

So you use a different method from HoppyUK (setting the HFD using the scale, and then selecting an aperture)?
 
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BertieTBE said:
I'm sure you're right..keep telling myself the same thing in the hope it'll get easier but it's not working!:bonk:
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This is one of those things where you're trying to do your thinking sat at the computer, stop staring at the figures and go use them.

Make life simple, drive into the country, get your camera out, put on a wide angle lens and set f11, focus on a point of interest, if you're a million miles away from hfd ill eat my hat. But while you're there a small tweak of the focus ring will nail it, your subject isn't about to get bored and walk off. :bonk:

I'm crap at shooting landscapes, but focus is the least of my issues, it's the planning, weather forecasts and early mornings I can't be bothered with.

DoF is a proper issue when you're shooting a 3/4 angled face, aiming for shallow DoF to lose the background and trying to get both eyes reasonably sharp allowing for the subject moving a bit.
 
Hi, Like to make another suggestion that you can do in the house on a rainy day.
Ask the boss of the house, Wife,Mother,Girlfriend for some clothes pegs, set them on end in a line across a table or the floor and practice.
Also have a look at this http://www.youtube.com/watch?v=utahGy831FQ
But as stated above don't get to hung up on it, I think if you do you don't concentrate on the other aspects needed to get the scene in front of you.
JMO
Russ
 
russellsnr said:
Hi, Like to make another suggestion that you can do in the house on a rainy day.
Ask the boss of the house, Wife,Mother,Girlfriend for some clothes pegs, set them on end in a line across a table or the floor and practice.
Also have a look at this http://www.youtube.com/watch?v=utahGy831FQ
But as stated above don't get to hung up on it, I think if you do you don't concentrate on the other aspects needed to get the scene in front of you.
JMO
Russ
Click to expand...

Thanks Russ, great suggestion - very helpful. Will give that a try this afternoon. It's pretty rainy down here...

Good video too - useful for anyone new to HFD.
 
Bertie, re your posts above...

For the shot you've linked, you don't need hyperfocal distance focusing as there is tons of DoF anyway. HFD setting is only when you really need to maximise DoF, eg a stately home in the background, but you also want the flower beds just a few feet in front of you sharp.

HFD focusing is for getting maximum DoF in terms of total distance, and as such it always has infinity as the furthest point. It's not the same as optimising DoF in general photography, where both the near and far points you want sharp are a lot closer than infinity.

On the DoF Master link, the hyperfocal distance for the settings you've input is shown bottom right of the top panel.

The method of working I've suggested puts the subject distance you want sharp as priority, which seems logical to me, and then tells you what aperture to use. But you can do it the other way around - set the aperture first and then adjust focusing distance accordingly, but that may or may not cover the near foreground distance you want sharp.

The depth-of-field preview button is frankly useless for assessing DoF. If you want to check it, take a test shot and zoom in on the LCD.
 
graphilly said:
I just use the LCD and zoom and I've never had a problem to be honest. It's the same as taking a shot and checking it that way surely?
Click to expand...

:thinking: That's what I said.

Edit: maybe we're talking at cross purposes - I meant using the DoF preview botton to assess sharpness through the viewfinder, not in live view.
 
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HoppyUK said:
:thinking: That's what I said.

Edit: maybe we're talking at cross purposes - I meant using the DoF preview botton to assess sharpness through the viewfinder, not in live view.
Click to expand...

Maybe we are. I use the DoF preview and check it using the LCD and zoom, before taking a shot.
 
As others have said your cliif pic doesn't really have a foreground. It has a middle ground and background. Also in some cases atmospherics may play a major part in affecting image sharpness.
In the cliff picture I would just focus on the rocks (on the same plane as the people and leave it at that)
 
Thank you all for your replies!

The way Jeff Revel writes about HFD in 'From Snapshots to Great Shots' implies that it's something that apples to any landscape shot, but reading what many have said here, I now see that's not the case.

Much clearer now.

Thank you all again.
 
On my 5D3 I move the focus point down to what I consider close enough to be 1/3 of the way up the viewfinder. If that makes sense. I know what I mean anyway.
 
Gaz J said:
On my 5D3 I move the focus point down to what I consider close enough to be 1/3 of the way up the viewfinder. If that makes sense. I know what I mean anyway.
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Sorry Gaz, but that doesn't make sense. (You did ask, sort of.) The whole 1/3 thing is bad advice anyway, but even if it were good advice, that wouldn't be the way to do it.
 
StewartR said:
Sorry Gaz, but that doesn't make sense. (You did ask, sort of.) The whole 1/3 thing is bad advice anyway, but even if it were good advice, that wouldn't be the way to do it.
Click to expand...

Measure in your head the distance from the nearest detail to the horizon and focus a 3rd of that distance from the nearest point at around f13
 
Guess its a case of what works for you guys and what works for me on this one.

The nearest detail is whatever I can see at the bottom of the viewfinder, which is where I want my DOF to start.

A generation or two have probably grown up taking landscapes this way so it can't be that bad.
 
Gaz J said:
Guess its a case of what works for you guys and what works for me on this one.

The nearest detail is whatever I can see at the bottom of the viewfinder, which is where I want my DOF to start.

A generation or two have probably grown up taking landscapes this way so it can't be that bad.
Click to expand...

Yes. And the method for setting best sharpness from top to bottom is hyperfocal distance focusing.

Which doesn't include a third of anything.
 
Used to be easy when it was on the lens. Not so easy now. Still gets trotted out by landscape photographers on workshops etc.
 
Gaz J said:
Used to be easy when it was on the lens. Not so easy now. Still gets trotted out by landscape photographers on workshops etc.
Click to expand...

It's still easy - see post #6.

Yes, DoF scales on the lens barrel were handy, and a few primes still have them, but they usually only apply to full-frame and often either the scale or the lens distance markings are not always accurate.
 
HoppyUK said:
Go to the DoF Master site (as linked by Stewart) and draw up your own table for your camera format. For your lens, suggest 18mm, 24mm, 28mm and 35mm, at f/4, f/8, and f/16.
Click to expand...

Gave this a try and got this (note - this is for my Canon 600d (t3i) and Sigma 18-250).


HFD F 5.6 F. 8 F 11 F 16 F 22
18mm 3m 2m 1.5m 1m 0.5 m
24mm 5.5m 4m 2.5m 2m 1.5
28mm 5.5m 4m 2.5m 2m 1.5
35mm 11.4m 8m 6m 4m 3m

Does this look right?

Many thanks.
 
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