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Single point focusing question

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Jake64

Jake64

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Say I am taking a photo of a person's face and I decide to use a single focus point. Naturally, I would aim it for their eye and at a very open aperture, I'd get a sharp image of the person where it matters most and background bokeh. Simple enough except when shooting a portrait of two people that are next to each other. I want both of their faces to be in focus but how can I do that if I'm only using one focus point on one of them. This is especially true when using a shallow depth of field.
 
Two specialist tools are at your disposal. They're at the end of your legs. :-)

You move so that the approximately planar surface in space which is in focus intersects both their faces where you want.

If you have such power, you can make them move instead ( or as well ). This works with models, but with civilians you're better off doing the moving yourself, IMO.
 
Jake64 said:
Jake64 wrote:

Say I am taking a photo of a person's face and I decide to use a single focus point. Naturally, I would aim it for their eye and at a very open aperture, I'd get a sharp image of the person where it matters most and background bokeh. Simple enough except when shooting a portrait of two people that are next to each other. I want both of their faces to be in focus but how can I do that if I'm only using one focus point on one of them. This is especially true when using a shallow depth of field.
Click to expand...
For starters, you're not going to get two planes of focus just because you might use more than one focus point. You still only get one plane of focus. You have to decide where that plane is and how wide the plane of focus is. So, I'd still focus an eye maybe but maybe not the nearest. I'd also stop down a stop or two to make sure both were in focus.

The main point of this is that extra focusing points don't extend our focused range. Only depth of field does that. Another issue is you didn't mention the camera or lens here. When I said I'd stop down maybe two stops, I was considering my 85 f/1.4 where I might have started at f/2 and might go to f/4 if I had two people in the scene. I might even go to f/5.6. It depends on how far away the background is if I want it blurred.

Another thing. You're not using the term Bokeh correctly. Bokeh is the quality of the out of focus blurred areas. It is not those areas. You can't have "more" bokeh. You can only have more pleasing bokeh. You said you wanted background bokeh. What would have been right would have been to say you wanted the background to be blurred out of focus. You could have added you wanted the background to be blurred out of focus with creamy bokeh. Bokeh only describes how that out of focus area looks.

Take care. :-)
 
I made the mistake of reading the exif data of the photos that were done by my engagement photographer. Every single photos was set at f2 regardless of distance from me or my wife and regardless of whether we were on the same plane. Usually I'd stop down as well to get more depth but she didn't touch the controls once and photos came out sharp. Her approach baffles me and now has me trying to figure out where to focus and still get sharp shots at a wide aperture regardless of the distance from the subject.
 
Jake64 said:
Jake64 wrote:

I made the mistake of reading the exif data of the photos that were done by my engagement photographer. Every single photos was set at f2 regardless of distance from me or my wife and regardless of whether we were on the same plane. Usually I'd stop down as well to get more depth but she didn't touch the controls once and photos came out sharp. Her approach baffles me and now has me trying to figure out where to focus and still get sharp shots at a wide aperture regardless of the distance from the subject.
Click to expand...
heheh. I tend to do that as well at an event. Once I decide on an exposure, I set it and leave it. I should make adjustments sometimes for DOF but generally do not. She sounds like she did it the way Stephen suggested. You just possition yourself so both people are in the plane of focus. If this becomes intuitive for you, you can play at those wider apertures more often. I tend to play more around f/2.8 than f/2 though, even with my f/1.4 lenses. Sometimes at f/2 and sometimes even at f/1.4, but mostly not.
 
Guidenet said:
Guidenet wrote:
Guidenet said:
Jake64 wrote:

I made the mistake of reading the exif data of the photos that were done by my engagement photographer. Every single photos was set at f2 regardless of distance from me or my wife and regardless of whether we were on the same plane. Usually I'd stop down as well to get more depth but she didn't touch the controls once and photos came out sharp. Her approach baffles me and now has me trying to figure out where to focus and still get sharp shots at a wide aperture regardless of the distance from the subject.
Click to expand...
heheh. I tend to do that as well at an event. Once I decide on an exposure, I set it and leave it. I should make adjustments sometimes for DOF but generally do not. She sounds like she did it the way Stephen suggested. You just possition yourself so both people are in the plane of focus. If this becomes intuitive for you, you can play at those wider apertures more often. I tend to play more around f/2.8 than f/2 though, even with my f/1.4 lenses. Sometimes at f/2 and sometimes even at f/1.4, but mostly not.
Click to expand...
 
Jake64 said:
Jake64 wrote:

Say I am taking a photo of a person's face and I decide to use a single focus point. Naturally, I would aim it for their eye and at a very open aperture, I'd get a sharp image of the person where it matters most and background bokeh. Simple enough except when shooting a portrait of two people that are next to each other. I want both of their faces to be in focus but how can I do that if I'm only using one focus point on one of them. This is especially true when using a shallow depth of field.
Click to expand...
  • To get both faces in focus with shallow Depth of Field, you need both faces to be exactly the same distance from the camera.

  • When they are both the same distance from the camera it doesn't matter which face you focus on, both will be in focus.

  • Everything in the photograph that is ALSO the same distance as the faces will ALSO be in focus.

  • Blur in the background is called blur. Bokeh is a word used to describe the nature of the blur.
 
Barrie Davis said:
Barrie Davis wrote:
Click to expand...
Barrie Davis said:
  • To get both faces in focus with shallow Depth of Field, you need both faces to be exactly the same distance from the camera.
  • When they are both the same distance from the camera it doesn't matter which face you focus on, both will be in focus.
  • Everything in the photograph that is ALSO the same distance as the faces will ALSO be in focus.
Click to expand...
Isn't that all rather misleading? Or are you redefining a plane as a sphere?
 
AnthonyL said:
AnthonyL wrote:
AnthonyL said:
Barrie Davis wrote:
Click to expand...
AnthonyL said:
  • To get both faces in focus with shallow Depth of Field, you need both faces to be exactly the same distance from the camera.
  • When they are both the same distance from the camera it doesn't matter which face you focus on, both will be in focus.
  • Everything in the photograph that is ALSO the same distance as the faces will ALSO be in focus.
Click to expand...
Isn't that all rather misleading? Or are you redefining a plane as a sphere?
Click to expand...
You are right.

Strictly speaking the focus points of virtually all lenses do fall on a more or less flat plane, which is at 90° to the lens' axis..... but equi-distant is close enough for practical purposes.

--
Regards,
Baz
:
"Ahh... But the thing is, these guys were no ORDINARY time travellers!"
 
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In retrospect, I feel like a bit of a fool. Upon closer inspection, sometimes I am out of focus and sometimes my wife is. It is dependant on who is closer to the camera. I am not sure how I missed this, I guess it was rather subtle and I couldn't really see until I zoomed right in. Silly me, I should have known that if two subjects are not on the same plane that at f2, one of them would be slightly out of focus which is definitely the case.

Lesson learned: don't look at another photographer's exif data and try to emulate what they did.
 
Jake64 said:
Jake64 wrote:

In retrospect, I feel like a bit of a fool. Upon closer inspection, sometimes I am out of focus and sometimes my wife is. It is dependant on who is closer to the camera. I am not sure how I missed this, I guess it was rather subtle and I couldn't really see until I zoomed right in. Silly me, I should have known that if two subjects are not on the same plane that at f2, one of them would be slightly out of focus which is definitely the case.

Lesson learned: don't look at another photographer's exif data and try to emulate what they did.
Click to expand...

I'm a amateur but if two were posed together that close with the husband slightly behind the wife as is often the case seems focusing between the cheekbone and ear, or on the hair at ear level of the wife would give the closest balance between the two.
 
Barrie Davis said:
Barrie Davis wrote:
Barrie Davis said:
AnthonyL wrote:
Barrie Davis said:
Barrie Davis wrote:
Click to expand...
Barrie Davis said:
  • To get both faces in focus with shallow Depth of Field, you need both faces to be exactly the same distance from the camera.
  • When they are both the same distance from the camera it doesn't matter which face you focus on, both will be in focus.
  • Everything in the photograph that is ALSO the same distance as the faces will ALSO be in focus.
Click to expand...
Isn't that all rather misleading? Or are you redefining a plane as a sphere?
Click to expand...
You are right.

Strictly speaking the focus points of virtually all lenses do fall on a more or less flat plane, which is at 90° to the lens' axis..... but equi-distant is close enough for practical purposes.
Click to expand...
Equi-distant is fine for two subjects. It can be misisleading and incorrect to say "Everything in the photograph that is ALSO the same distance as the faces will ALSO be in focus" especially when talking of shallow Depth of field. The other two points you make are of course correct. We have had beginners' questions on here where they expected everything equi-distant to be in focus and not appreciating that there is a plane of focus.
 
AnthonyL said:
AnthonyL wrote:
AnthonyL said:
Barrie Davis wrote:
AnthonyL said:
AnthonyL wrote:
AnthonyL said:
Barrie Davis wrote:
Click to expand...
AnthonyL said:
  • To get both faces in focus with shallow Depth of Field, you need both faces to be exactly the same distance from the camera.
  • When they are both the same distance from the camera it doesn't matter which face you focus on, both will be in focus.
  • Everything in the photograph that is ALSO the same distance as the faces will ALSO be in focus.
Click to expand...
Isn't that all rather misleading? Or are you redefining a plane as a sphere?
Click to expand...
You are right.

Strictly speaking the focus points of virtually all lenses do fall on a more or less flat plane, which is at 90° to the lens' axis..... but equi-distant is close enough for practical purposes.
Click to expand...
Equi-distant is fine for two subjects.
Click to expand...
Yes. The fact that two faces conventionally posed within the frame would naturally fall on BOTH a flat plane and the inside of a dome the surface of which was equidistant from the camera, was a point I was going to make myself, and then decided against it as unnecessary complication.

Thing is, I try to make a point of answering the OP's actual question, rather than pour out a whole bunch of stuff designed to show off how much I KNOW.
AnthonyL said:
It can be misleading and incorrect to say "Everything in the photograph that is ALSO the same distance as the faces will ALSO be in focus" especially when talking of shallow Depth of field.
Click to expand...
Just how misleading do you think it is, in the context of ancillary image content, that is, stuff that isn't the subject?

Remember, anything that is NOT sharp in a wide aperture photograph, can safely be assumed to have been at the wrong distance to be in focus......

..... and, let's face it, there are a WHOLE BUNDLE of different distances that are unsharp in all wide aperture shots that are not a picture of a flat plane.
AnthonyL said:
The other two points you make are of course correct. We have had beginners' questions on here where they expected everything equi-distant to be in focus and not appreciating that there is a plane of focus.
Click to expand...
I know that, and take pains to correct that impression when the shape of the image plane itself is the question.

--
Regards,
Baz
:
"Ahh... But the thing is, these guys were no ORDINARY time travellers!"
 
Last edited:
Barrie Davis said:
Barrie Davis wrote:
Barrie Davis said:
AnthonyL wrote:
Barrie Davis said:
Barrie Davis wrote:
Barrie Davis said:
AnthonyL wrote:
Barrie Davis said:
Barrie Davis wrote:
Click to expand...
Barrie Davis said:
  • To get both faces in focus with shallow Depth of Field, you need both faces to be exactly the same distance from the camera.
  • When they are both the same distance from the camera it doesn't matter which face you focus on, both will be in focus.
  • Everything in the photograph that is ALSO the same distance as the faces will ALSO be in focus.
Click to expand...
Isn't that all rather misleading? Or are you redefining a plane as a sphere?
Click to expand...
You are right.

Strictly speaking the focus points of virtually all lenses do fall on a more or less flat plane, which is at 90° to the lens' axis..... but equi-distant is close enough for practical purposes.
Click to expand...
Equi-distant is fine for two subjects.
Click to expand...
Yes. The fact that two faces conventionally posed within the frame would naturally fall on BOTH a flat plane and the inside of a dome the surface of which was equidistant from the camera, was a point I was going to make myself, and then decided against it as unnecessary complication.

Thing is, I try to make a point of answering the OP's actual question, rather than pour out a whole bunch of stuff designed to show off how much I KNOW.
Barrie Davis said:
It can be misleading and incorrect to say "Everything in the photograph that is ALSO the same distance as the faces will ALSO be in focus" especially when talking of shallow Depth of field.
Click to expand...
Just how misleading do you think it is, in the context of ancillary image content, that is, stuff that isn't the subject?

Remember, anything that is NOT sharp in a wide aperture photograph, can safely be assumed to have been at the wrong distance to be in focus......

..... and, let's face it, there are a WHOLE BUNDLE of different distances that are unsharp in all wide aperture shots that are not a picture of a flat plane.
Barrie Davis said:
The other two points you make are of course correct. We have had beginners' questions on here where they expected everything equi-distant to be in focus and not appreciating that there is a plane of focus.
Click to expand...
I know that, and take pains to correct that impression when the shape of the image plane itself is the question.
Click to expand...
 
Guidenet said:
Guidenet wrote:
Guidenet said:
Barrie Davis wrote:
Guidenet said:
AnthonyL wrote:
Guidenet said:
Barrie Davis wrote:
Guidenet said:
AnthonyL wrote:
Guidenet said:
Barrie Davis wrote:
Click to expand...
Guidenet said:
  • To get both faces in focus with shallow Depth of Field, you need both faces to be exactly the same distance from the camera.
  • When they are both the same distance from the camera it doesn't matter which face you focus on, both will be in focus.
  • Everything in the photograph that is ALSO the same distance as the faces will ALSO be in focus.
Click to expand...
Isn't that all rather misleading? Or are you redefining a plane as a sphere?
Click to expand...
You are right.

Strictly speaking the focus points of virtually all lenses do fall on a more or less flat plane, which is at 90° to the lens' axis..... but equi-distant is close enough for practical purposes.
Click to expand...
Equi-distant is fine for two subjects.
Click to expand...
Yes. The fact that two faces conventionally posed within the frame would naturally fall on BOTH a flat plane and the inside of a dome the surface of which was equidistant from the camera, was a point I was going to make myself, and then decided against it as unnecessary complication.

Thing is, I try to make a point of answering the OP's actual question, rather than pour out a whole bunch of stuff designed to show off how much I KNOW.
Guidenet said:
It can be misleading and incorrect to say "Everything in the photograph that is ALSO the same distance as the faces will ALSO be in focus" especially when talking of shallow Depth of field.
Click to expand...
Just how misleading do you think it is, in the context of ancillary image content, that is, stuff that isn't the subject?

Remember, anything that is NOT sharp in a wide aperture photograph, can safely be assumed to have been at the wrong distance to be in focus......

..... and, let's face it, there are a WHOLE BUNDLE of different distances that are unsharp in all wide aperture shots that are not a picture of a flat plane.
Guidenet said:
The other two points you make are of course correct. We have had beginners' questions on here where they expected everything equi-distant to be in focus and not appreciating that there is a plane of focus.
Click to expand...
I know that, and take pains to correct that impression when the shape of the image plane itself is the question.
Click to expand...
Don't worry, Barrie. I think we all know where you were going with this. Your intent was to answer the question without being overly pedantic in a way no beginner would really understand well.
Click to expand...
Hmmm... You are gracious, Craig.

Even so, in view of the objections raised to the terms I used in my first posting here, in answering this question again I'll certainly try harder to AVOID giving the impression that the lens focuses on a spherical field.
Guidenet said:
Take care, my friend.
Click to expand...
Thank you... 'preciate it.

--
Regards,
Baz
:
"Ahh... But the thing is, these guys were no ORDINARY time travellers!"
 
Last edited:
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