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A study in dimensions for photographers

Adjusting dimensions by relying on a camera that allows us to change its lens is a powerful visual method, although some understand it incorrectly, so international photographer Brian Peterson provides us with hard facts on this subject with illustrative images that help the photographer reach the best results.

- The ability to adjust the dimensions in the image
To achieve the effect of an expanding or compressed space, it is one of the most powerful visual aids in photography. It is also widely misunderstood, as among the most beloved and persistent of photography myths one concerns lens dimension, and experienced photographers often speak of tele-wide-angle, or telephoto. Telephoto, there is also a widespread belief that aspect ratio is a matter of focal length. And it really isn't.
The task of the focal length is that it determines the scale of the image, so the focal lengths are high. It always produces images that are larger than those produced by shorter lenses of the same distance. Although the focal length is linked with the structure of the film, the two determine the viewing angle. The 90 mm lens is used today on 35 mm cameras - 24 x 36 mm - and on 4 x 5 inch cameras - 98 x 120 mm - . On the L35 camera, the 90mm lens gives a narrow 27-degree angle, so we define it as a moderate telephoto lens. As for the 4 x 5, the 90mm is a wide angle lens. secured to an extension of 81 degrees.

The lenses see reality in three dimensions and record abstractions in two dimensions, and the dimensions refer to relative dimensions of the image that give a sense of depth to the two-dimensional image. Dimensions are affected by only three things: the distance between the lens and the subject, the viewing angle towards the top or bottom, and the movements of the back of the grained glass of the view cameras.
The long distance between the camera and the subject flattens and compresses the impression of depth because the angles of the light rays, which reach the lens from different subjects at different distances—such as a man at 50 feet, a house at 500 feet—are about the same. from this distance. The man and the house may be at the same scale on the film and appear as if one is directly above the other.

In this field, we put the camera very close to the man, only five feet away from him, for example, so we have reduced the distance between the lens and the house by 4 feet. The image taken from this second location shows the man being magnified, while the house is retracted towards miniaturization, which gives a great sense of three-dimensional depth.
Now, of course, long-distance shots are usually made with long-focus telephoto lenses, and for close-up photography a short-focus wide-angle lens is the obvious way to go. However, this has nothing to do with dimensions at all.
We choose the lens, the telephoto. The big shot is the long distance until we get large enough images to see them, without resorting to additional zoom or even cropping the image.

From close distances, all lenses give relatively larger images, and thus. You see, this is a detractor, to say nothing of the fact that most long focus lenses have limited implied close-focus power. Thus, we choose the lens for long or short shooting range between image scale and viewing angle.
When using a wide-angle lens to help achieve a telephoto, deep-space effect, there is a potential dilemma of sideways distortion of solid objects near the edge of the film frame.

We also have to remember that focal length actually affects depth of field:
The series of distances from which objects appear appropriately visible. This, the depth of field improves with shorter focal lengths, longer capture distances, and smaller stops. As for longer lenses, wider lenses - faster - and shorter distances, they reduce the depth of field.
In the field of practice as photographers, we use the depth of field with the effects of the dimensions of straight lines to achieve the desired visual effect. For example, the low-focus background resulting from a shallow depth of field pushes the subject of sharp focus to stand out strongly. And the great depth of field, with sharply focused subjects from close to infinity, enhances the sense of a deep expanse of space.

One of the best ways to learn what is related to dimensions, and use that in photography, is to work with a zoom lens, especially. One that starts with a short focal length, like 28 or 35 mm, and gives a high zoom ratio, like 3: 1 or more. Now, it will be easy for us to conduct experiments using different focal lengths from the same capture site, and by changing the focal length when moving to a distance closer to the subject or farther from it.
We can use the focus circle in the center of the (SLR) screen to notice the scale of a part of the subject, and then maintain the scale when capturing from a great distance with a long focal length, and from a close distance with a short focal length.
It is possible to start by trying some professional tricks such as popping the background by increasing the capture distance and taking a higher focal length to maintain the image scale with a large section (tight).
Then we try to exaggerate the sense of depth of the subject by getting close using the short focal length to leave the angle of the lens wide enough to show us what we want⏹

⏺ Dimensions of a flat "telephoto" with a standard 50mm lens:

Using the same location as the tripod, Brian Peterson happened to create the colored transparency with a 50mm lens, then switched to a 300mm telephoto lens for the second exposure. We point out that the compressed dimensions of the 300 mm snapshot are recognized immediately because the images are large and the snapshot is very short, but the dimensions of the telephoto. Exactly the same is hidden within the snapshot of the
50 mm. As evidenced by the massive magnification of the center of the original codachrome. It should be noted that the extreme magnification is less sharp in prominence, but it completely repeats the same feeling with flat dimensions, such as a 300 mm telephoto shot. These pictures prove that telephoto dimensions are, in fact, called long distance dimensions.

⏺ Dimensions of a normal lens within a 20 mm wide-angle lens:

Contrary to the measures adopted, Peterson is now shattering that so-called myth. Wide angle dimensions, with a picture with a 20mm wide-angle lens, and another with a 50mm standard focus lens, with the use of the same fixed location of the tripod, the large range of the wide angle shot with the rail lines retracting dramatically, shows different dimensions.
Here is a snapshot made by enlarging the middle of a snapshot with a 20mm lens. These are experiments that should be repeated for the sake of self-conviction, and it will be easier to make them more with a zoom lens with a wide field of view. It is sufficient to fix the location and capture from different focal length locations, and the proof will appear in our photos⏹

⏺ Between the camera, how does the distance and the subject control the dimensions of your photo? !

Distance By applying the principles of distance, photographer Peterson produced three different photos of a fashion model. Photo (a) was made with a distance between the camera and the subject of seven feet, with a wide-angle 88 mm lens. Note the relatively small photo of the bridge in the far background, and for photo (b), I backed off
Camera up to 50 feet back, and I used a 200mm lens to record the same scale.
Notice how dramatically the background stands out and how the space looks compressed.
In picture (c), the same distance of 50 feet from the fence was maintained, but the 28 mm lens was used again, and the model placed herself seven feet from the camera to maintain her pictorial scale.
If a huge enlargement was made for (c), it would show the same dimensional relationship between the fence and the bridge as in (b), because the 200 mm and 28 mm images were made from the same location.
The point to remember is that interchangeable lenses allow you to choose the focal length you need to scale an image and crop a subject, but the distance comes from the camera distance⏹

A fish-eye view:

While looking straight down from a helicopter a few hundred feet up.
Peterson used a 28 mm wide-angle lens to cover a large area of ​​the area at this noticeable height and without converging lines. The scene is characterized by flat dimensions, with only shadows indicating that trees and other objects have a three-dimensional height.
In order to mitigate this flat appearance, it will be necessary for the helicopter to fly at a lower altitude - a shorter distance between the camera and the subject - and for the camera to operate at an angle of approximately 45 degrees. Still, this kind of aerial view looking straight down adds a fun abstract element to an otherwise mundane subject.⏹

A view of a worm's eye:
The camera's very low location blends with the 50mm lens angled upwards to produce the effect of wide-angle extension in vertical building lines that recede dramatically, and with the assistive presence of foreground plants as we twist our necks back until we look up at a skyscraper. The buildings of the city are not pyramids with pointed heads, but the camera is an unbiased witness whose three-dimensional realism condenses into a two-dimensional image that can only hint at the existence of real depth and distance relationships ⏹

⏺ Avoid wide angle distortion:

When you work with a wide-angle lens, beware of the distortions that it emits in three-dimensional objects located close to the edges of the image frame, and the corners. This distortion is especially noticeable with human faces, as Peterson explains with his image. The only solution is to keep your subject in the central region of the image⏹

⏺Dimensions and facial images:

Dimensions are usually seen in terms of geometric shapes, especially those that include horizontal or vertical straight lines, but the human face is a case in which the process of adjusting dimensions is more difficult.
And we have to - know - faces by watching them from certain distances. Exaggeration in approaching (1) is dangerous because the nose and chin, which are much closer to the lens, appear large in an ugly way, as in the facial image made with a 20 mm lens from a distance of just over one foot.
The beautiful face shown in (B) came thus backwards to a distance of 105 mm, which is widely regarded as an ideal lens for 35 mm portraits. Perhaps most impressive are the flat facial dimensions of the 15-foot cat (C), made with a 300mm telephoto lens.
It is natural that exaggeration in getting far can flatten facial features to a large extent, what is considered far to the maximum is a matter of taste, but exaggeration in getting close is always dangerous, regardless of the focal length of the lens ⏹