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Chapter 8 - Esthetics: Zoom, POV, Depth of Field and Bokeh |
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Field Of View (Zoom) The focal length of your lens determines the magnification it delivers. You change the focal length of the H-Series cameras by zooming in or zooming out. If your focal length is small (36 mm is the smallest in the H1 through H5, 31 mm in the H7 and H9), subjects appear smaller and more distant and your field of view is wider. This is called wide-angle. You zoom out to wide-angle. If your focal length is large (432 mm maximum on the H1 through H5, 465mm on the H7 and H9), subjects appear larger and closer and your field of view is smaller. This is called telephoto. You zoom in to telephoto. For the purposes of The White Paper, all focal lengths are expressed in 35 mm equivalents. In order to compare lenses and cameras to one another, the photo industry needed to establish a common standard. It chose the 35 mm frame size as the baseline, since the vast majority of lenses built and sold over the last few decades were designed for that format. The H-Series lens is quite small. It doesn't need to be as large as a lens for a 35mm camera because the sensor (our digital "frame") is six-times smaller. This is called the FOV Crop Factor. Which means that if you multiply any focal length of the an H-Series lens by 6, you'll get the focal length on a 35mm film camera that will produce the same view of the scene. The real focal range of the H-Series lens is 6 - 72 mm (5.2 - 78 mm on the H7 and H9). The equivalent, effective focal range of the H1 though H5 lens is 36 - 432 mm, 31 - 465 for the H7 and H9. It's not important to understand the calculations behind crop factor. But, when you read your photo's EXIF information or your camera's display, remember to multiply it by 6 to arrive at a useful, standard expression of focal length.
Depth of field (DOF) is that portion of your image, extending out from your lens, that appears to be in focus. I say "appears" because, in reality, there is only one single, infinitesimal point that's truly in focus - one point that has no ghosts, halos, soft edges or smudges. Anything in front of that, anything behind that, becomes progressively more blurry and indistinct as it moves away from that point.
Fig. 8-1 Depth Of Field The area surrounding that point which most viewers will accept as appearing to be in focus is called the depth of field.
Try this experiment. Put your hand up against the wall.
Look at it. The hand and the wall are pretty much in the same plane. Both appear to be in focus. Your lens, in this regard, is not very different from your eye. Whether you do it consciously or not, you alter the depth of field every time you focus on a subject, zoom your lens or change your aperture. You can just leave it to chance, or better, control it and use it to add beauty, mystery, mood and powerful new points-of-view to your photographs.
Every photo has a "phantom viewer" standing somewhere, facing a certain direction with a defined field of vision and a point of focus. That "phantom viewer" doesn't have to be "at the camera". Lenses allow us to place our viewers almost anywhere we want. Which means that our "viewers" can see the same scene from many perspectives depending on where we put them. What the "phantom viewer" sees is called the point of view of the image. The easiest way to change the point-of-view is to change the focal point of your lens. It's generally accepted that the "normal" point of view, the point at which your camera and your viewer are in the same plane, is around 50-55 mm. That's reputed to be the focal length at which your camera sees what your naked eye sees. Zoom in closer and you move the point of view forward from the camera toward the subject. Zoom out to wide-angle and the phantom viewer's point of view moves back closer to the camera - or even behind it.
You can change the point of view on the H-Series cameras just by zooming their remarkable lenses. Or you can extend your options by adding a telephoto adapter, wide-angle adapter or closeup lens. Or you can change the point of view by manipulating depth of field. Let's use the same composition and camera position as the previous example, but zoom in much closer and focus on the bench, not the background.
Where is the barbed wire? It's still there in the picture, but it's so close to the point of view and so out of the depth of field (so out of focus) that you can no longer see it.
Now let's use the exact same scene, position and zoom, but focus on the barbed wire instead of the bench.
Just like the hand in front of your face in our earlier example, the background has pretty much disappeared. The bench is no longer recognizable. These four photos illustrate radically different points of view taken from the same position with the same camera and subject, just a few seconds apart. Note how changing the point of view changes not just the look, but the impact and the message of the images. Surely the rusted barbed wire in the last shot conveys an entirely different emotion and esthetic than the first shot with its shadows and long-view. This is about choices. The more tools you have, the broader the palette you have to choose from as a photographer and artist, the more control you have in setting the point of view of your photographs and the more freedom you have to express yourself to the viewer. Fortunately (and perhaps surprisingly), the H-Series cameras are among the best of the small digicams for controlling and exploiting depth of field. However, using that capability requires that you think about depth of field while taking pictures. In my lexicon, the four primary elements of great photography are composition, focus, exposure and depth of field. If you're not thinking about depth of field when you set up your shots, you're just not getting the best pictures you can from your H-Series camera.
Depth of field can be used to ensure that all the critical elements in your photo appear to be in focus. This is particularly true of landscape shots, where you often wish to show as much detail as possible. In that case, you'll use a deep depth of field.
But for portraits and flowers, you may want to isolate your subject, to bring it "forward", to de-emphasize a background that competes for attention. This requires a shallow depth of field.
The depth of field on the following shot is so tiny (courtesy of an add-on closeup lens) that it's barely the length of the bee. That's one of the major issues in macro photography - getting enough depth of field for a very small subject without distracting background information diminishing the impact of the shot.
Fig. 8-9 Macro Depth Of Field You're the photographer. You make the rules. And there may be times when you want to do a landscape shot with a relatively shallow depth of field like the one below.
Or a floral study with a deeper depth of field to emphasize the overall composition instead of a single flower.
Your choices are almost unlimited. Depth of field is a powerful tool to help you ensure that your viewers experience your photos the way you intend.
Depth of field comes in all sizes. It can extend from a point close to the camera out to infinity. Or it can be so small that you can see the head of a fly in great detail while the body is just a blur. It can be centered on the foreground, the background or anywhere inbetween. There are almost unlimited possibilities, and choosing among them is the art of photography. The skill part is learning to control them. Depth of field depends on four factors:
All other factors being equal, cameras with larger sensors generally exhibit less depth of field, cameras with smaller sensors more. This is not strictly due to the size of the sensor so much as the size of the photo sites. Smaller "pixels" look sharper than larger ones. The Sony H-Series cameras have very small sensors, so you wouldn't expect them to be able to easily produce a shallow depth of field. You wouldn't expect it to do flowers with beautiful blurred backgrounds. But it does. Its other features, including its relatively bright lens, its huge telephoto zoom range and its amazing closeup capabilities compensate for the smaller sensor size. In any case, you can't change the size of the photo sites in your sensor, so it's simply not a factor you need to take into account when composing a shot. It is what it is. Another factor you can't change is your camera's Circle Of Confusion (COC) - a measurement of the accuracy of the light coming from your lens as it intersects the focal plane of your camera. The circle of confusion changes at different apertures resulting in different depths of field (see below). If you want to understand COC better, click here for a site with a very simple and accurate explanation. Aperture The aperture is the opening that allows light to come into your camera. A larger aperture admits more light; a smaller aperture, less. Aperture is measured in f/stops. And though it may seem counter-intuitive, lower f/stops represent larger apertures; higher f/stops represent smaller ones. F/2.8 is quite a bit larger (and admits more light) than f /8. In any mode except AUTO and Shutter Priority, you get to determine what size aperture is used for any given shot (within the limitations of your camera, of course). Which is good, since aperture size can have a dramatic impact on depth of field:
Therefore, f/2.8 yields a shallow depth of field, f/ 8 yields a deep one - which translates into a couple of simple rules:
But there are two issues that diminish the effectiveness of using aperture to control depth of field when shooting with the H-Series cameras. First is the diffraction effect. All lenses, as they get to their smallest apertures (highest f/stops), suffer to some degree or another from diffraction effect. Instead of getting sharper, as you might expect, they actually lose some acuity. If you're using a high f/stop to get lots of clarity in a photo, the highest f/stops may be counterproductive. Taking diffraction effect into account, the realistic working range of the H1 - H5 is probably only from f/2.8 to f/7.1. Avoid f/8. The H7 and H9 cameras have smaller pixels, which generates diffraction effect at a lower f/stop. For those cameras, you'll want to keep your aperture down to f/6.3 maximum. Which brings us to the second problem. Like most other small digicams, there's not a lot of usable aperture range in the H-Series lenses. SLR lenses often range from f/1.4 to f/32 or even higher. They have a lot more "play" even after you drop the highest f/stops. If we eliminate f/stops that suffer from diffraction effect, there are only three-and-a-half f/stops available for controlling depth of field in the H-Series cameras: f/2.8, f/4, f/5.6, f/6.3. Not a lot of options. Because of this limitation, changing the aperture on an H-Series camera will have far less effect on depth of field than it does in some other kinds of cameras. But that doesn't mean no effect. I find changing the aperture to be an excellent way to fine-tune my depth of field.
Fig 8-13 Shallow DOF From f/3.7
Fig. 8-15 Somewhat deeper DOF from f/7.1 You also have the option of shooting all the way up to f/ 8 and sharpening the entire photo in post-processing to compensate for the sharpness lost to diffraction effect. The downside is that you might end up over-sharpening what you intended to be a soft, blurred background. Nothing compares to getting it right in the camera.
Wide-angle shots (smaller focal lengths) yield more depth of field, telephoto shots produce less. As you zoom your lens between the two extremes, you will get more or less depth of field depending on where you stop. The closer to telephoto, the shallower the depth of field. The closer to wide-angle, the deeper. In the photo below, the H1 was zoomed to full telephoto (432 mm) and positioned about five feet back from the flower. Note that only the single flower appears to be in focus
Fig 8-16 Extreme Telephoto DOF In the next photo, the zoom was backed all the way off to full wide-angle (36 mm) and shot closer (approximately 2.5 feet) to try to maintain the size of the subject..
Fig. 8-18 Deep DOF from wide-angle focal length You can easily see that the depth of field in the top photo is much shallower than the depth of field in the second. Much more of the second photo appears to be in focus. Tip: If you want to subtly increase the depth of field, just back off your zoom a bit. Of course, that changes the point of view of the shot. To achieve the same point of view, just crop the image in post-processing.
Subject Distance Subject distance is the distance between your lens and your subject. Your subject is the object, animal or person you're focusing on. Subject distance has a major impact on depth of field in two ways:
To keep it simple, depth of field is determined, to a large extent, by where you focus. Check out the two following photographs. Both were shot from the exact same position, both used identical settings. The only difference was focus. In the first image, the camera was focused on the berries; in the second photo on the tree behind.
Fig 8-21 Shallow DOF from focusing on foreground
Fig 8-23 Deeper DOF by focusing farther away from the camera. The two pictures above demonstrate an important point. Depth of field diminishes both behind and in front of the subject. It surrounds your subject. You may have noticed that, in the second picture, both the foreground and the far background are out of focus. David Pogue, writing in the New York Times, claimed that this was not possible without a DSLR. Well, David, all you need is a shallow depth of field in the distance to blur the foreground. Or a shallow depth of field in the middle distance to blur both the background and the foreground. The H-Series cameras do both very well.
We already know that camera-to-subject distance is one of the main determinants of depth of field. But what about subject-to-background distance? Technically, it has no effect on depth of field. No matter where your background is, your depth of field doesn't change. But it's still a major issue in composing your shots, since the background can be within your subject's depth of field, or entirely outside of it. If the background is within the subject's depth of field, it will appear to be in focus. If it's outside of it, it will appear blurred. In the earlier sections, we discussed creating and managing depth of field. But the endgame, the whole point of depth of field, is to be able to decide what falls within the depth of field and what does not. There are two ways you can do this. One is to alter the depth of field by adjusting the settings of your camera and lens. Another way is to position the background so that it's included in the subject's depth of field - or not. If you wish to isolate your subject, to draw attention to it and away from a busy background, you need to separate your subject from your background sufficiently to keep the background out of the subject's depth of field. In the following example, there are two significant elements: the clear glass marbles in a track at the bottom of the picture (the subject) and the coffee mug above and behind (the background). In the first photo, the marbles are at the front of the track, close to the camera, and as far from the mug as possible:
Fig. 8-24 Distant background
Fig. 8-25 Background beyond the DOF The marbles look sharp, the mug does not - because the mug is too far away to share the marbles' depth of field. Now let's use the exact same camera position, leave the marbles and mug where they were, but focus on the mug instead of the marbles:
Fig. 8-26 Far focus
Fig. 8-27 Background in DOF, foreground not. As you might expect, the marbles are now out-of-focus. Due to the change in focus, the mug is now the subject. And the marbles aren't close enough to the mug to share its depth of field. Now let's move the marbles back so they're almost touching the mug. Leave the focus on the mug as it was in the previous picture.
Fig. 8-28 Foreground and background close together.
Fig. 8-28 DOF shared by foreground and background. Now both the marbles and the mug appear to be in focus - because we've moved the marbles into the depth of field of the mug. What we've done, in this example, is move the subject and background so that the background moved in or out of the foreground's depth of field. When it moves in, it looks sharp. When it moves out, it looks blurry. When you wish to isolate a subject, you need to separate it enough from the background that its depth of field doesn't spill over onto the background. You need to separate the subject from the background. Separation is relative. For instance, with a very tiny depth of field, such as a macro shot of an insect, the separation needed to blur the background may be only millimeters. On the other hand, all other factors being the same, shooting a tree in front of a mountain may require much more separation.
Foreshortening is a side-effect of increasing subject distance. The farther you get away from the subject, the closer the subject appears to be to its background. Remember that the farther you get from the subject, the deeper its depth of field becomes. So, if you shoot a tree in front of a mountain from a mile away, its almost certain that the tree's depth of field will be large enough to include the mountain behind. Both will appear to be in focus. On the other hand, if you zoom in on a tree that's only five feet from your lens, its depth of field will be so small that there's no way the distant mountain can share it. The tree will appear in focus, the mountain will not. Here's a crop of the same picture used above, but shot from about 15 feet away (same zoom, same aperture, just further away)
Fig 8-29 Foreshortening
Fig. 8-30 Shooting from a long distance can cause foreshortening Even though it doesn't look that way, the marbles are actually at the very end of the track closest to the camera. The illusion that they are much closer to the background is called foreshortening. Both appear to be in focus. This all may seem very complicated. And it is. But that's because it offers the photographer an infinity of options - a very broad palette. Just remember that if you can't get the depth of field you want using camera settings, you always have the option to:
It helps if you visualize your finished photo before you shoot it. Think about depth of field. Think about where you're positioned, where your subject is, where your background is. While we're at it, here's a shot that demonstrates yet another option. I added a close- up lens to my camera so that I could get even closer to the marbles, and got this interesting little composition. Note that the depth of field is miniscule, only the size of a single marble, and that the mug in the background has blurred beautifully to a soft, elegant backdrop (bokeh). This makes perfectly good sense. The closer you get to the subject, the shallower the depth of field. Close up lenses let you get much closer at telephoto than you normally can with the native H-Series lenses alone. ( For more on close up lenses, click here to jump to the Close Up And Macro chapter.)
Fig. 8-31 Extreme closeup using close-up lens.
Bokeh (pronounced BO KEH'), is a Japanese term describing blur. People often misuse the term by referring to the amount of blur or where the blur resides in a photo. In fact, "bokeh" refers only to the quality of the blur. A lens is said to have good bokeh or bad bokeh, not more bokeh or less bokeh. In recent years, it's become fashionable to use blur as an integral part of photo composition. Earlier eras of photography were hell-bent on getting every detail as crisp as possible. Today's approach is more artistic, morphing yesterday's "failures" into a powerful, flexible, sophisticated and modern photo esthetic. The bokeh produced by your camera is only partially under your control. Mostly, bokeh is determined by your lens. Some lenses have beautiful, soft painterly bokeh through a wide range of focal lengths. Others won't produce a beautiful blur no matter what you do. It depends on the amount of spherical aberration in your lens and how that aberration affects the light passing through to the focal plane. Click here for a more technical and comprehensive discussion of bokeh by Ken Rockwell. It's well-worth the read! Fortunately for us, the H-Series cameras consistently deliver beautiful bokeh that varies depending on the focal length of the lens for any given shot. Let's take a look at the rich variety of bokeh produced by the H-Series cameras. Use the following illustration as a guide. It's a photo I took from a fixed point in my home, focused out the sliding glass doors at the scene outside. You'll note that the distances to various features are called out in this picture. Each circle represents a subject used in our demonstration.
Fig 8-32 Scene with distances called out. As we move our focus from the most distant subject (the trees) in toward the silk plant placed within 8 feet of the camera, the bokeh will change in both nature and quality. Note how the bokeh changes in these pictures, but even more important, how the bokeh changes the pictures! The bokeh in these shots reveals radically different points of view from the same scene and the same camera position. Note: These pictures were taken in the rain, in the midst of a heavy storm. The trees in the background were being blown about - which resulted in a little streaking in the bokeh from motion blur - and the outdoor subjects were drenched. An interesting opportunity. This is the shot with the greatest apparent depth of field. It's a long shot (over 75 feet) focused on the trees in the background. You shouldn't expect to see any bokeh when the subject and the background are the same. After all, both the subject and background are in the same depth of field. But note that you do get some foreground bokeh. Not very good, but again, this is just a demonstration.
In the next picture (Bird In Rain), we focus on the planter, approximately 18 feet from the camera's lens. The bokeh is only moderately blurred. The depth of field is large enough that some of it is catching the trees beyond. Remember that the further your subject gets from the camera, the deeper the depth of field. Note: the washed-out look is due to the fact that the photo really is washed out. The background is being viewed through approximately 60 feet of heavy rain.
At 18 feet, we've already lost most of the detail of the background. But it's at an awkward point, neither buttery nor crisp. Nonetheless, it's esthetic enough for this photo, even if it doesn't represent the ultimate bokeh an H-Series camera can produce. The following picture may not demonstrate the H-Series' ultimate bokeh, but it's close enough. This is the soft background that results when you focus on a subject well away from the background (67 feet). The curlicues are the fronds on the silk plant in the foreground. The soft bokeh of this photo creates a whole new image, abstract and isolated, similar to the barbed wire in our point of view example.
Here's a different bokeh. This one wasn't shot at full zoom, so the points of light in the background are more distinct, less painted. Note the shape of some of the points of light - they reflect the blades of the iris of the lens.
Tip: To eliminate the polygonal shapes, shoot at the widest aperture (lowest f/stop), at which point the blades are retracted completely out of the way, producing the smoothest, most-circular blur points.
It would be terrific to be able to provide a list of settings that produce all the different bokehs and different depths of field that the H-Series cameras are capable of. But bokeh and depth of field are so subjective, so dependent on so many factors, that the list would have to be endless. You have to experiment - to think about depth of field and apply it to your photos. In digital cameras, shots are free. Take the same scene with different settings, play with your camera until you get the effect you want. In a short time, you'll develop a repertoire of effects for the kinds of pictures you take. Here are some general rules to help guide you: To get the deepest depth of field - the sharpest photos:
To get shallow depth of field - to isolate subjects from backgrounds:
To switch between foreground and background blur:
Don't let that paralyze you. There's nothing worse than not thinking about the options and ending up with a drawer full of poor-quality snapshots that no one wants to share. That's overstating the case just a bit. The H-Series is a remarkable collection of cameras that can deliver excellent photos despite the best efforts of photographers to take bad ones. But the cameras can do so much more, can deliver such excellent, quality, expressive photos that you're doing yourself a disservice if you don't take advantage of the amazing capabilities of Sony's H-Series.
Fig. 8-36 Foreground Bokeh Chapter 9 Extending
Your Reach: Add-On Lenses |
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