Picture Perfection
Created | Updated Dec 14, 2002
A portrait when taken through a lens is ruled by the laws of optics and some simple suggestions can make for a better picture. I have included video terms and references in this submission since more and more people are shooting digital moving video and 'grabbing' stills from it. Many of these suggestions are also good for video interviews such as recording family history.
Depth of field<1> is perhaps the most important but most often ignored aspect of picture taking. By severly restricting the plane of focus (the area that is in sharp focus) to just the subject all attention is brought to it and not to the backround or foreground. In extreme close-ups the eyes are most often the visual point of interest so they should be the sharpest focus. The two simplest methods of achieving this are by using a long lens and/or the widest iris <2> setting possible (the lowest f-stop number <3>). Without getting into the optical characteristics that create this effect these two methods can be most easily achieved in two different ways. First a zoom lens <4> at it's longest zoom or longer non-zoom lens can be used with a greater distance between the camera and subject. Alternatly the light level reaching the film, tube face, or chip which will capture the image can be reduced electronically (a video shutter <5>) or physically (stills and video) thereby neccesitating opening the iris. A lower light level is the simplest way of doing this but in film or digital still photography this is usually achieved through varying the aperture <6> and in video photography it is usually done with higher shutter speeds. Another less common method is putting a 'Neutral Density' or ND filter in front of the lens to reduce the light level entering the camera. Ideally a 'wide open' (lowest f-stop number) iris setting is preferrable, so set the aperture or shutter to achieve that.
The next consideration is the optical distortion <7> caused by a lens. If the subject is physically too close to a relatively wide angle lens (generally less than 7mm in video or 55 mm in stills) there is lens distortion which will 'flatten' or distort a face. Unless the effect wanted is for comedy, this should be avoided. Similarly too long of a lens (telephoto) foreshortens <8> pictures, stacking anything in picture into a 'crowded' shot.
In this simplified view of portraiture the final and perhaps most important element is light. I have always held to the belief that one should not light a subject, but rather create darkness (shadow) in an interesting way. Drama is provided by shadow, interest by providing the angular and concave shapes of the face and body with less light. That said it is also important to provide a hightened 'edge' to a portrait with a light source coming somewhere off camera behind the subject (a back light <9>). Avoid 'flares'<10> from this and other light sources by shadowing the lens with a solid object like a lighting 'flag'<11> or the 'barn doors'<12> of the lamp. Keep your lenses clean with quality lens paper to prevent ambient light catching any smudges or dust.
Flash photography can achieve pleasing looks, but generally only with expensive multi-flash slaved setups (the kind you see in a professional photo portrait studio). These set-ups have a number of large flash units that are highly diffused and synchronized. If you have a flash that tilts back try a cheaper alternative using a small white piece of cardboard attached to the back of the flash with rubber bands for 'bounce'. The strong light is then diffused and raised from the plane of the lens and it's intensity is more like the ambient light of the rest of the picture.
Everyone should produce their own 'look' so I would encourage experimentation. As simple as this guide is it should provide all the basic rules to produce interesting, individual pictures of people whether in film, digital images, or video.
1-The part of a picture which is in sharp focus. A shallow depth-of =field is an area roughly the same distance from the camera which is in focus.
2-The iris is a mechanical part of the camera which varies the amount of light entering the camera.
3-The f-stop is a measurement of the amount of light the iris allows to enter the camera. Due to the physics of the arangement the measurement indicates more light with a smaller number. Each number is double or half of the amount of light of the numbers next to it on the iris settings. The reason for this measurement is the Inverse Square Law which states that the amount of light reaching a subject is inversely proportioned to the distance from the source that is to say one over the distance squared. If you think of the light leaving the source as an ever expanding cone you can see the logic of this law.
4-A zoom lens allows the frame of the picture to be enlarged or made smaller through internal movement of lenses creating longer or shorter millimeter measurements of the lens.
5-A shutter physically or more often electronically interrupts the light entering the camera a number of times a second.
6-Aperture is the amount of time of exposure in still photography.
7-Lens distortion is caused by the thinner outer section of a lens due to optics. The thicker centre of the lens is therefore sometimes referred to as the 'sweet spot'.
8-Foreshortening appears to 'pile up' foreground, subject, and backround so that little space appears to be between them.
9-A back light is a light which highlights the back edge of a subject, separating it visually from the background.
10-Flares are light reflected within the optics of a lens creating phantom images, often blue smears or white streaks.
11-Flags are solid panels which block light, usually flat black to avoid reflections.
12-Barn doors are the built-in flags on a light which prevent light reaching anything other than the subject.
Depth of field<1> is perhaps the most important but most often ignored aspect of picture taking. By severly restricting the plane of focus (the area that is in sharp focus) to just the subject all attention is brought to it and not to the backround or foreground. In extreme close-ups the eyes are most often the visual point of interest so they should be the sharpest focus. The two simplest methods of achieving this are by using a long lens and/or the widest iris <2> setting possible (the lowest f-stop number <3>). Without getting into the optical characteristics that create this effect these two methods can be most easily achieved in two different ways. First a zoom lens <4> at it's longest zoom or longer non-zoom lens can be used with a greater distance between the camera and subject. Alternatly the light level reaching the film, tube face, or chip which will capture the image can be reduced electronically (a video shutter <5>) or physically (stills and video) thereby neccesitating opening the iris. A lower light level is the simplest way of doing this but in film or digital still photography this is usually achieved through varying the aperture <6> and in video photography it is usually done with higher shutter speeds. Another less common method is putting a 'Neutral Density' or ND filter in front of the lens to reduce the light level entering the camera. Ideally a 'wide open' (lowest f-stop number) iris setting is preferrable, so set the aperture or shutter to achieve that.
The next consideration is the optical distortion <7> caused by a lens. If the subject is physically too close to a relatively wide angle lens (generally less than 7mm in video or 55 mm in stills) there is lens distortion which will 'flatten' or distort a face. Unless the effect wanted is for comedy, this should be avoided. Similarly too long of a lens (telephoto) foreshortens <8> pictures, stacking anything in picture into a 'crowded' shot.
In this simplified view of portraiture the final and perhaps most important element is light. I have always held to the belief that one should not light a subject, but rather create darkness (shadow) in an interesting way. Drama is provided by shadow, interest by providing the angular and concave shapes of the face and body with less light. That said it is also important to provide a hightened 'edge' to a portrait with a light source coming somewhere off camera behind the subject (a back light <9>). Avoid 'flares'<10> from this and other light sources by shadowing the lens with a solid object like a lighting 'flag'<11> or the 'barn doors'<12> of the lamp. Keep your lenses clean with quality lens paper to prevent ambient light catching any smudges or dust.
Flash photography can achieve pleasing looks, but generally only with expensive multi-flash slaved setups (the kind you see in a professional photo portrait studio). These set-ups have a number of large flash units that are highly diffused and synchronized. If you have a flash that tilts back try a cheaper alternative using a small white piece of cardboard attached to the back of the flash with rubber bands for 'bounce'. The strong light is then diffused and raised from the plane of the lens and it's intensity is more like the ambient light of the rest of the picture.
Everyone should produce their own 'look' so I would encourage experimentation. As simple as this guide is it should provide all the basic rules to produce interesting, individual pictures of people whether in film, digital images, or video.
1-The part of a picture which is in sharp focus. A shallow depth-of =field is an area roughly the same distance from the camera which is in focus.
2-The iris is a mechanical part of the camera which varies the amount of light entering the camera.
3-The f-stop is a measurement of the amount of light the iris allows to enter the camera. Due to the physics of the arangement the measurement indicates more light with a smaller number. Each number is double or half of the amount of light of the numbers next to it on the iris settings. The reason for this measurement is the Inverse Square Law which states that the amount of light reaching a subject is inversely proportioned to the distance from the source that is to say one over the distance squared. If you think of the light leaving the source as an ever expanding cone you can see the logic of this law.
4-A zoom lens allows the frame of the picture to be enlarged or made smaller through internal movement of lenses creating longer or shorter millimeter measurements of the lens.
5-A shutter physically or more often electronically interrupts the light entering the camera a number of times a second.
6-Aperture is the amount of time of exposure in still photography.
7-Lens distortion is caused by the thinner outer section of a lens due to optics. The thicker centre of the lens is therefore sometimes referred to as the 'sweet spot'.
8-Foreshortening appears to 'pile up' foreground, subject, and backround so that little space appears to be between them.
9-A back light is a light which highlights the back edge of a subject, separating it visually from the background.
10-Flares are light reflected within the optics of a lens creating phantom images, often blue smears or white streaks.
11-Flags are solid panels which block light, usually flat black to avoid reflections.
12-Barn doors are the built-in flags on a light which prevent light reaching anything other than the subject.
