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I've read more than once that the closest eye to the camera should be focused on a portrait of a person or of a group of people.

Here is an example (faces are blured for discretion, pay attention to the unblurred eyes). Although all faces should be in focus, some of them are a little shapier than other ones.

enter image description here

But why not focus on the person who is not the closest one to the lens neither the farest one, so on average, all faces in the picture will be more focused than the first approach?

My proposal is to switch from this: side representation of a group of people portrait, focusing on the model closest to the lens

to this: side representation of a group of people portrait, focusing on the model in the middle

The least sharp face on the second approach will be sharpier than the least sharp face on the first approach, right?

In the example picture, it would mean changing the focus from the right eye of the closest guy to the lens to, maybe, the guy in blue.

Even if sharpness is not evenly distributed (there's more depth of field behind the focus than in front of it), as it is said in this related question, even though it seems reasonable to focus maybe on the second face closest to the lens.

mattdm
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Heitor
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5 Answers5

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There's more depth of field behind the focus than in front of it. So focussing on the near eye gives you the best chance of getting the whole face in focus. If you can't do it focussed on the near eye, you can't do it without changing something (position, angle, aperture).

In addition, you'be got a good chance of a clear view of the near eye, making focussing (manual or auto) easy to get right. By clear view I mean free of things like hair, or fur/feathers in animal portraits; for wildlife if you can't get the near eye in shot without a twig in the way it's not going to be a good shot.

It's only a rule of thumb, but one of those useful rules which you can apply if you don't want to think too much.

Chris H
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  • Sensible I suppose, but you've entirely ignored the third and subsequent eyes - both the humorous potential, and the misunderstanding expressed in the OP's question. – mc0e May 16 '17 at 14:42
  • @mc0e the humorous potential was handled by mattdm better than I could, so I ignored it for the answer. While the use of "all", and "closest" rather than "closer" imply a group, I assumed a single subject with two eyes for the sake of wording. The same reasoning actually applies to a larger number of eyes. Also Michael Clark's answer read like it assumed a single face, and it's rare for me to be able to add anything to what the resident experts write. – Chris H May 16 '17 at 14:56
  • At closer focus distances, the DoF is almost evenly divided between front and rear of the point of focus. Please see: Why is the area in focus in front of the focus distance narrower than behind it? – Michael C May 16 '17 at 21:51
  • @MichaelClark, your answer there agrees with what I read when writing this, though the emphasis is different. Your examples with a wide aperture at minimum focus giving 1:1 mean my "more" could change to "never less and often more". For most portrait work you're not going to be at the minimum focus, but you're going to be closer to that than the hyperfocal distance. Note that I didn't quote the 2:1 approximation which relies on too many assumptions. – Chris H May 17 '17 at 05:53
  • Yes, but with typical portrait focal lengths and distances the ratio is still VERY close to 1:1. Notice the example in the linked answer: at 300mm and f/4 at an 11 foot focus distance the difference between front and rear DoF is less than a hundredth of an inch. At 30 feet the near DoF is 1.50 inches, the far DoF is 1.51 inches with a FF camera when displayed at 8x10 and viewed from 25cm by a person with 20/20 vision! Even with an 85mm lens at f/2 and a focus distance of 15 feet the front DoF is 2.35 inches, the rear DoF is 2.41 inches for a difference of only 0.06 inches. – Michael C May 17 '17 at 06:37
  • @MichaelClark not being a portrait expert those apertures seem very wide (selected to minimise DOF when the question is closer to maximising it). What effect does that have? And that's all ignoring the still unanswered "is it a group portrait?" possibility, where focal lengths will be shorter or distances longer. – Chris H May 17 '17 at 07:09
  • The question is a bit nebulous at that point, but even using smaller apertures at typical portrait focal lengths and distances doesn't increase the difference between front and rear DoF that much, it just increases the size of both. Please see the additions to my answer. In a case where a narrower aperture is used, the margin for error would be greater and it is far more likely that no difference between two eyes on the same face would even be noticeable at all. The question as asked is most critical when wider apertures, not narrower ones, are used. – Michael C May 17 '17 at 07:27
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    @MichaelClark plugging in some numbers the same calculator as you (now I'm in front of a PC) I can see where you're coming from. But I can easily get bigger numbers using different assumptions: 8x10, 25cm, default vision, 35mm, f/11. Then an 85mm lens at 2m gives 1.83--2.21m. Thats +8.27, -6.9 inches. That's enough DOF to get a wide hat in focus -- if you focus on the near eye. As I said in the answer, it's a rule of thumb -- you have to pick somewhere to focus; it should be somewhere important, convenient, and that doesn't lead to odd effects. Near eye does this easily. – Chris H May 17 '17 at 08:04
  • ...I may edit the answer when the OP comes back to clarify. – Chris H May 17 '17 at 08:05
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    Keep in mind that by f/11 pretty much any digital camera currently on the market is already past the diffraction limited aperture, too. Manufacturer standard is pretty nebulous since different camera and lens makers use different circles of confusion (and the calculator doesn't ask if the lens is, for example, a Zeiss, who assumes a viewer with 20/15 vision for their self-published DoF data). – Michael C May 17 '17 at 08:21
  • @MichaelClark The rule of thumb dates back to 35mm though (and I've probably shot more portraits on 35mm than digital too). I did wonder about which manufacturer. – Chris H May 17 '17 at 08:28
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    Zeiss has been using a CoC based on 20/15 vision for decades. The DLA in the film era varied based on the size of the chemical grains in the emulsion of whatever film was loaded in the camera, so it changed every time you used a different kind of film. – Michael C May 17 '17 at 08:42
  • "There's more depth of field behind the focus than in front of it", that answered a lot. But still, why not focus on the person, let's say, second closest to the lens? – Heitor May 22 '17 at 06:56
  • Now you've clarified it's a group, if the person nearest the middle (in distance terms) or slightly closer to you is clearly visible and clearly lit, focussing on then may be good. In your example you've got a lot of depth compared to group shots in which people are spread across the field of view. The role of thing may come more from the latter situation. And it's worth looking at the discussion under this answer: Michael's comments on the division of the acceptably sharp region are important, especially with the DOF you need for a big group. – Chris H May 22 '17 at 07:04
  • With the additional info and example from the OP, it seems wide apertures are a consideration in this case, seeing as how the photo is taken in what appears to be a fairly dark bar or tavern. – Michael C Sep 12 '18 at 18:48
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Because the way human vision perceives a two dimensional representation of the three dimensional human face if the nearest eye is in focus it looks to us more like the whole face is in focus.

Even if the question is regarding group portraits (the question is rather nebulous at this point) it still holds true. A group portrait with the front person(s) in sharpest focus looks more natural to our eyes than a group portrait where a face in the middle of the pack is sharper than the closest faces.

Returning to reasonably tight portraits of a single person with two eyes:

Although the rear depth of field (DoF) will theoretically be larger than the front DoF, at typical portrait focal lengths, apertures, and subject distances the difference is so negligible as to not even be measurable except under very well controlled laboratory conditions.

The following all assume an image from a 35mm or full frame camera being viewed at an 8x10" display size from a distance of 10 inches (25cm) by a person with 20/20 vision and figured using the advanced options here:

  • Using a 300mm lens and f/4 at an 11 foot focus distance the difference between front and rear DoF is less than a hundredth of an inch.
  • Using a 300mm lens and f/4 at a 30 feet focus distance the near DoF is 1.50 inches, the far DoF is 1.51 inches. That's a ratio of 1.0066:1 or a difference of only 0.66% between front and rear DoF!
  • Using an 85mm lens at f/2 and a focus distance of 15 feet the front DoF is 2.35 inches, the rear DoF is 2.41 inches for a difference of only 0.06 inches. That's a F/R ratio of 1.0256:1 or a difference of only 2.56%.

enter image description here

Even if we use much narrower apertures the difference is still negligible.

  • Using a 135mm lens at f/8 focused from a distance of 20 feet, the front DoF is 6.51 inches and the rear DoF is 6.88 inches, a difference of only 0.37 inches. That's a F/R ratio of 1.057:1 or a difference of only 5.7%.

enter image description here

Michael C
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    This. When we look at a person, we'll usually focus on the nearer side. An unsharp near eye and a sharp far one will look really weird (unless done with artistic intent i guess). – ths May 16 '17 at 13:49
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One more possibility, which would also apply to group portraits:

An old rule of thumb is that out of focus objects ahead of the point of focus are less pleasant to the eye than out of focus objects behind the point of focus; in other words, you generally want to keep the foreground clear of out of focus objects as much as possible, or the viewer may feel disturbed. (this can of course be used on purpose for artistic effect)

Focussing on the nearest eye will tend to keep the OOF area behind the point of focus for most subjects; this applies regardless of the number of eyes per subject. :-)

jkf
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  • Because "out of focus objects ahead of the point of focus are less pleasant to the eye than out of focus objects behind the point of focus" ---> I think that's the answer. That's why it might be a good idea to focus on maybe the second closest person to the lens, but not on the person in the middle. – Heitor May 22 '17 at 07:04
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Although my immediate thought was reflected in @mattdm 's comment (funny) I guess you mean when shooting groups, so that there are more than two eyes in the shot.

In that case you're not really bound to pick the closest eye, IMO.

You need to choose a point of focus that creates a composition you like. I'd probably go with e.g. rule of thirds or something like that to decide how to frame/compose the shot and what to focus on. Which person seems the most important/attractive/biggest tipper is also something to give some thought to.

I don't think for groups you have to obey quite the same rule as you would for single person shots.

My guide in this case would be, to quote a great movie, "look into your heart". I think a lot of people forget their instincts and think in terms of rules, but a portrait should be about the emotional response to and from the people in it, so start there and focus on what works to convey what you see.

StephenG - Help Ukraine
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  • That's an excellent point, but only after you bear in mind that sometimes "there's more depth of field behind the focus than in front of it" and that "out of focus objects ahead of the point of focus are less pleasant to the eye than out of focus objects behind the point of focus". So a rule could be "follow your heart but pick up someone in the front". – Heitor May 22 '17 at 07:07
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In the example of your photo, focusing on the near eye also has the benefit of keeping the DOF narrower on your group. You want your group to be in focus, not the people in the background. When everything is in focus in a photo, the eye has more difficulty (OK, it's your brain) in figuring out where to look/what's important. Of course, if your aperture is set at f11, the background still is in focus.

BobP
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