​​​​بيان سرعة لغالق الملائمة لتصوير الأجسام المتحركة المختلفة.كتاب أسس التصوير الضوئي

Determine the appropriate shutter speed for photographing different moving objects:

Notes from the appropriate shutter speed table for photographing moving objects

Linking this table between two factors:

a) The speed of movement of the body is estimated in kilometers per hour.

b) The distance between the moving object and the camera is estimated in metres. Based on the two previous factors, the appropriate shutter speed was estimated. This estimate was based on the consideration that the body moves horizontally with respect to the axis of the lens and that the lens has a medium focal length. If the direction of the body's movement changes, the following should be taken into account:

a) If the movement of the body is perpendicular to the camera, the time estimate is increased by three times. For example, if the body moving horizontally needs a speed of one second, then this same body needs a shutter speed of arrows of a second if its movement is perpendicular to the camera.

b) If the movement of the body is the same, whether its movement is towards the camera or in the opposite direction, then the time estimate is increased + 1 times from what was stated in the table. The second, if its movement is oblique to the axis of the lens:

If the focal length of the lens changes, consider the following:

c) If a telephoto lens is used, the speed estimate will increase, for example if the table. The former estimated the speed of a gel of a second for a lens of medium focal length, using a telephoto lens
(×2) The speed is doubled to 1/200
from the second.

d) Conversely, the shutter speed is slowed by using a lens with a short focal length or an obtuse angle.

Moment of rest:

If we notice some moving objects, we find moments when the body stops moving, and let us take an example of a child swinging “the swing” moves from one side to the other, but there are two periods in which the speed of the swing movement decreases and they are when the swing reaches the maximum heights and we head towards the descent. The moment in which the swing begins to change the direction of its movement to the other direction is considered a period of rest for the movement, and the moments of the knife movement often occur in bodies whose movement is periodic, that is, in which the body moves in a certain direction and then stops and then returns to the other direction, and this happens to all of us during Walk if we notice the movement of our hands

There are other moving bodies whose movement speed decreases in moments, although they do not move in a periodic movement, i.e. they do not return to the other direction. Let us imagine a horse or a dog jumping on a support, or athletes in jumping competitions. The body moves in a certain direction and at a certain speed, even if it rises to the top. The dam or barrier slows its movement speed, then tends to descend at a speed that is almost equal to its speed before the desert. If the photographer can record this movement stillness period
(And this is not needed except for exercise) because it will not need a very high shutter speed.

It is noted in Figure 85 that due to the speed of movement while jumping with the camera and the moving object near, therefore the shutter speed should have been high. However, it was possible to reduce the shutter speed to a scale of one second. Because the movement was recorded at the moment of changing the speed of the body, which is when the dog began to change its direction and tended to go down. the distance between
We note that by photographing the body at a change of speed, it has been possible to record the fast movement with a relatively slow shutter speed. On the other hand, it has been possible to narrow the aperture of the diaphragm, thus obtaining a large depth of field, as it is noticed in the image the sharpness of the details of the building that is far from the body in an instant:

Moving the camera in the direction of body movement: Panning Technique

The maximum shutter speed of the camera that we use may be insufficient to record the rapid movement of the body, and here some photographers follow the method of moving the camera in the direction of the movement of the body while exposing the film, which is the only appropriate method for this case: Photographing during exposure contributes to reducing the ratio of the speed of movement of the object being photographed to the moving camera in the same direction. In order to do this, we give an example of a car traveling at a speed of one hundred kilometers per hour, and its movement appears very fast compared to a person standing still in the street, but it appears at a slower speed if the person is riding another car traveling in the same direction and its speed is 800 kilometers per hour. If we assume that this person wants to photograph the car : in the first case
(While standing in the street) He needs a high shutter speed that we may estimate by a pocket of a second. In the second case, the shutter speed estimate is much less than when he was standing in the street, and it is estimated, for example, from a second, with other factors remaining constant. Perhaps this equilibrium may have explained the effect of moving the camera while exposing the film in the direction of the moving object, as if the movement of the camera is.

Move the camera in the direction of the fast-moving object:


Photographing with a lens with a long focal length of 270 mm, type Tele Exnar Lens, with an aperture of a normal lens from the Thalia, and a proper shutter speed, which is a speed that would not have produced the apparent result unless the camera had moved in the direction of the competitors’ movement, and the pen used was very sensitive. . It is noted that the images of the spectators are not clear because they were stationary in relation to the moving camera.

Quoted from Gross Bild Technique