focus on two subjects.

gingrjenny

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This is probably a basic question but I am not sure what to do. When I take a photo of a person I'm supposed to focus on the eyes so they are sharp and in focus. What if you are taking a photo of two people? I can't get the red focus dot on both right? So do I do whoever is closer or just pick one? Increase my f stop so the entire photo is more in focus?
 

cgipson1

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It requires enough DOF (Depth of Field) to cover both subjects... this is primarily a function of the aperture, focal length, and distance to the subjects...

Check this out... Online Depth of Field Calculator
 

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Yes, you need sufficient depth of field to "cover" the two subjects. Stopping the lens down a bit, to say f/8, might be required with a telephoto lens from clsoer distances. With a shorter focal lerngth, and smaller image magnification, you might be able to get two people shown full-length from head to toe, in good enough focus at say, f/4.

The higher the magnification, meaning the bigger the subjects are in the image, the shallower the depth of field is. so,on a tight, head-and-shoulders portrait of a man and woman, it might be necessary to stop the lens down to say, f/13, if he is in back of her and is eight inches behind her. On the other hand, if you can get their faces side-by-side, at basically the same distance to the camera, then the depth of field needed might only be a 4-inch deep band, and you might very easily be able to "cover focus" at f/5.6.
 

Gavjenks

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OR use a tilt shift lens!

Keep your narrow DOF and tilt it to hit both of their eyes, but still keep all your background blur. Or add more blur that would have been completely impossible before. Combine people at diagonals or verticals too, etc. etc.

^
Not a great solution for a beginner at all (they require experience and patience and fiddling and more $$$ than comparable normal lenses), but it is a solution (IMO a better solution in most cases), that I feel obligated to mention.
Not unattainable by any means though. A lensbaby composer lens and edge 80 optic (which is a true, sharp, tilt lens unlike their other products, not shift though) is <$500. There's a Ukrainian company that makes some for around that price too that are okay apparently (Arsat).
 
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gingrjenny

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This photo I took I feel like they were both at about the same DOF. But one is more in focus and the little boy is blurry. f/6.3, 1/125, iso 1600(i had it set on auto)
 
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bratkinson

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Without knowing what lens and camera you are using and how far the children were from the camera, it's impossible to determine how 'thin' the depth of field was on the above picture. I'm guessing slightly more than a foot of DOF, where everything within that field is in focus.

Assuming you are using a Canon Rebel or similar crop body with a 50mm lens from about 7' away at f6.3, that would give you about 16" depth (thickness) of focus area. As the boy is about a foot behind the girl, her face would be roughly in the middle of the 16" total DOF, giving 8" either way would still be in focus. At 12" behind the girl, the boys face is slightly out of focus. In this situation, simply moving back 3 feet (no change to aperture) would double the DOF to almost 3 feet, and both the children would be in focus. With the focus on her eyes, the DOF would be 18" to the front and rear of her eyes. He, being 12" to the rear, would be in focus as well.
 

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This photo I took I feel like they were both at about the same DOF. But one is more in focus and the little boy is blurry. f/6.3, 1/125, iso 1600(i had it set on auto)
The DoF is an area extending across the scene in front of and behind your point of focus that will have acceptably sharp focus. That area does not have sharp edges at the front and rear distance limits.

Actually focus is sharpest at the point of focus and the focus sharpness starts getting softer as distance in front of and behind the point of focus increases.
If DoF is shallow that sharpness fall off happens over a very short distance.
As DoF gets deeper, sharpness fall off happens more gradually.

In the image you posted, with a shutter speed of only 1/125, if the boy was moving slightly during the exposure he is blurred from motion rather than from being out of the DoF.

The point of focus distance relative to lens focal length has the biggest effect on the total DoF available.

DoF is the single hardest photography technical concept new photographers have to learn, because DoF is affected by several interlocking variables.

Here is a tutorial that shpould help, but find others becuase it helps you learn by reading a variety of explainations.
Understanding Depth of Field in Photography
 

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View attachment 50274
This photo I took I feel like they were both at about the same DOF. But one is more in focus and the little boy is blurry. f/6.3, 1/125, iso 1600(i had it set on auto)

I think what you meant to say here was that the children are at "about the same distance from the camera" not at "about the same DOF".

As mentioned, DoF is one of the trickier fundamentals to get your head around. You just have to keep at it and it'll sink in eventually.

One thing to keep in mind is that wherever you focus, there will be a certain distance in front of and behind that point that will be "acceptably sharp", with the larger portion being behind.

If you have a Canon crop-sensor camera with a 50mm lens set to f/5.6, and you stand 10 feet away, you should have plenty of DoF to get two kids situated as shown in your example. To be safe, and if there is light to spare, you might want to hit f/8.
 

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Just out of curiosity, was the boy holding pretty still, or was he moving around a bit? Even at 1/125, a bouncy, energetic kiddo will give you some motion blur. Might be a little bit of that going on in this photo, in addition to the fact that the DOF does seem to be a bit in front of them (look at where her hand is on the tree).
 
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gingrjenny

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i was probably about 15 feet away. I think my camera was at 70mm. I don't feel like i'm ever going to get this DOF thing.
 
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gingrjenny

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Just out of curiosity, was the boy holding pretty still, or was he moving around a bit? Even at 1/125, a bouncy, energetic kiddo will give you some motion blur. Might be a little bit of that going on in this photo, in addition to the fact that the DOF does seem to be a bit in front of them (look at where her hand is on the tree).

he was probably moving a little more than the girl. That kid never holds still
 
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gingrjenny

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View attachment 50274
This photo I took I feel like they were both at about the same DOF. But one is more in focus and the little boy is blurry. f/6.3, 1/125, iso 1600(i had it set on auto)

I think what you meant to say here was that the children are at "about the same distance from the camera" not at "about the same DOF".

As mentioned, DoF is one of the trickier fundamentals to get your head around. You just have to keep at it and it'll sink in eventually.

One thing to keep in mind is that wherever you focus, there will be a certain distance in front of and behind that point that will be "acceptably sharp", with the larger portion being behind.

If you have a Canon crop-sensor camera with a 50mm lens set to f/5.6, and you stand 10 feet away, you should have plenty of DoF to get two kids situated as shown in your example. To be safe, and if there is light to spare, you might want to hit f/8.

so If I focus on what is closer the area behind should be more in focus. So if I would of changed to f/8 I would of had to slowed down my shutter speed even more? I was already at high iso.
 

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I don't feel like i'm ever going to get this DOF thing.
As long as you continue using negative self speak like that you will be right.
You're smart enough to figure it out if you're willing to devote the time and effort it takes to understand it.

None of us learned it in one fell swoop. It takes time.

I wonder? Do you ever visit your local library? They have an entire photography section and will loan you books for a couple of weeks at a time for no charge.
 
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gingrjenny

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It just seems complicated. I read about it and it doesn't make sense. I understand that the smaller f stops will give me the bokeh and that larger ones will be more sharp all over. after that I'm lost

View attachment 50274
This photo I took I feel like they were both at about the same DOF. But one is more in focus and the little boy is blurry. f/6.3, 1/125, iso 1600(i had it set on auto)

I think what you meant to say here was that the children are at "about the same distance from the camera" not at "about the same DOF".

As mentioned, DoF is one of the trickier fundamentals to get your head around. You just have to keep at it and it'll sink in eventually.

One thing to keep in mind is that wherever you focus, there will be a certain distance in front of and behind that point that will be "acceptably sharp", with the larger portion being behind.

If you have a Canon crop-sensor camera with a 50mm lens set to f/5.6, and you stand 10 feet away, you should have plenty of DoF to get two kids situated as shown in your example. To be safe, and if there is light to spare, you might want to hit f/8.

so If I focus on what is closer the area behind should be more in focus. So if I would of changed to f/8 I would of had to slowed down my shutter speed even more? I was already at high iso.
 

Gavjenks

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smaller f stops will give me the bokeh and that larger ones will be more sharp all over. after that I'm lost
Keep in mind that f/stops refer to diameter of the opening / focal length. So smaller numbers like f/1.8 let in more light than f/16. You seem to already understand this just fine, but my reason for mentioning it is that usually people say f/1.8 is a larger aperture than f/16, or a "wider f/stop" or whatever, referring to the larger light path. So it may be confusing to communicate if you say smaller, referring to the actual number. Just a heads up.

Anyway, I would have started with f/8 here, and checked in camera then adjusted if necessary. Motion blur is also a possibility. If it's dark and you're at lower shutter speeds, try snapping off 4-5 pictures so later there's more chance of one being non-motion-blurred, if you have a fidgety kid.

Also, why is it so damn dark in that tree? f/6.3, 1/125, iso 1600 ??? That's what, 6 stops slower than sunny 16? Seems a little excessive for just being in a tree. Was this in the evening, or in a ravine, or something? If there's any way to get a lighter location or time, that would help with being able to do more DOF + fast shutter.

Also, if you shoot RAW you can underexpose by a stop or so on purpose pretty easily, then push it back to normal in post processing. In order to gain speed.
 

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