Detailed explanation and question answering of slow door photography system
Slow door, also known as long exposure, is a strange and familiar concept, and is also a topic that every photography enthusiast cannot bypass. Many new people often hear it but do not know how to use it. In fact, it is not as complicated as everyone thinks. After reading this article, you can get started!
1、 What is a slow door?
Slow shutter is also known as long exposure. When the camera converts a real scene into a picture, there are several key factors that affect the final imaging effect – shutter, focal length and aperture. Slow shutter, as the name implies, refers to a photography technique that reduces the shutter speed to extend the slow shutter time, which is different from the conventional method of instant freeze.
2、 What is the function of slow door?
The first slow gate is just to make up for the limitation of the lens aperture and the lack of sensitivity, and to ensure sufficient exposure by extending the exposure time.
However, with the progress of technology, many people have discovered other unique functions of long exposure, such as light painting, car tracks, softening the water surface, hiding moving objects, etc., which turns the instantaneous activity of taking photos into a long-term record. This is the function of the slow door, and also its attraction.
3、 What equipment does the slow door need?
In fact, the threshold for playing slow door is very low. Don’t be frightened by yourself before you start,（1）Just have a camera that supports the slow door function.
（2）Of course, for better effect, a wireless shutter (shutter line) is also needed to reduce the vibration of the camera:
（3）A tripod for stabilizing the camera:
（4）Filter, in order to reduce the light flux:
4、 What theme is suitable for slow door?
Scenery! Slow doors are often used in both urban buildings and natural scenery. First, they are used to soften the sky or water, form a unique long exposure effect and enhance visual impact; The second is to obtain more light and enrich the exposure details.
Of course, in addition to scenery, it is also used for the focus effect in motion:
Light painting effect at night (including star track and car track):
Long exposure effect of hidden crowd:
Play ghost with re exposure:
5、 How to slow down the door
(1) How to set parameters?
To ensure long-term exposure, the aperture and sensitivity should be reduced accordingly, and the light acquisition is mainly determined by the length of time.
(2) How to judge the slow door time?
Try! Now, unlike the long exposure with film, we can only judge the length of time by experience and light meter. Now, digital cameras can take pictures and see them at once. If the picture is dark or the effect is not enough, the shutter time should be appropriately extended; If you are overexposed, you will shorten the time. Try two or three times, and you will gradually accumulate experience.
(3) What is an ND filter?
The ND filter also becomes a medium gray density mirror, which can be used for non-selective filtering of light, that is, the attenuation effect of light of various wavelengths is the same, so it will not change the actual effect of the picture, but it is equivalent to adding a piece of filter paper to let the light pass through the lens more slowly. Because the slow door requires a long exposure time, sometimes the picture is too bright for a long time, which is easy to explode, reducing the flow of light, and making it more controllable.
In addition, there is also a GND filter, also known as medium gray gradient filter. As the name implies, the light flux is gradually reduced through gradient. It is often used in pictures with large light ratio and strong contrast between light and dark. The most common is to darken the sky, so that the sky and the ground can obtain more appropriate exposure at the same time.
(4) What is a black card?
Shake the black card and the GND filter have similar functions, which is equivalent to the handmade version of the GND filter. During the long exposure process, shake the black card in front of the lens from time to time to block the bright part of the picture, and obtain the appropriate exposure with the average overall light flux. Not only is the cost lower, but also the image quality loss caused by the filter can be avoided.
Long exposure for a short time can’t shake the black card. Long exposure has its advantages and disadvantages. The biggest advantage of the black card is manual control, and the biggest disadvantage is manual control. It allows you to control the amount of light reduction and area of the picture, but it depends too much on experience and opportunity.
(5) What is the difference between a square filter and a round filter?
The square filter is a universal filter, which is composed of a set of filters and a frame. Only one set of filters is needed, and all lenses can be used; The round filter is a special filter, which is connected to a separate lens, making it more difficult to replace.
The square filter is mostly a gradient lens, which is convenient to adjust the position for composition. The cost of the filter group is lower, but it is prone to dark angle and glare; The circular filters are mostly UV, CPL and ND lenses, which are fixed in front of the lens, and the shadow mask will not have dark corners, but the disadvantage is that they are not removable, and different apertures require different filters, which is more expensive.
6、 Key points in later stage
In fact, there is not much difference between the later stage of slow door and the conventional film, but there are two points to be mentioned. FirstHDR effectThe exposure details obtained from long exposure are rich enough. In addition, the overall exposure is uniform and accurate, and the dynamic control and details have been improved by using a gradient mirror or a black shake card. If HDR effect is added, it is easy to add to the picture. After all, it’s just an algorithm. If you really want HDR, you can just surround the exposure and stack directly. Why use the slow gate?
Secondblack and whiteThis is a small skill. Slow doors seem to match black and white by nature, because both of them are a cognitive way beyond our naked eyes. If you can’t grasp the later stage of slow doors, you might as well try to deal with it in black and white, and the temperament will change instantly.
7、 Summary
Finally, from the perspective of novices, how to get started with slow door:
That is to say, long exposure is just a photographic technique that extends the exposure time;
(2) The function of the slow door is to obtain more light, and the second is to create a special long exposure effect;
(3) The slow gate is mostly used for shooting scenery films to achieve the effect of delay; At the same time, it is also used for special effects such as focusing, light painting, ghosting, and hiding unnecessary elements.
(4) To shoot slow shutter, you need a camera that supports slow shutter, a tripod, a wireless shutter (shutter line), and a piece of ND or GND filter.
(5) When shooting, pay attention to the setting of exposure combination and try and summarize more. Pay attention to the use of GND and black card technology.
(6) In the later stage, try to control the HDR effect and try to process it into black and white.Is it very simple? You have already started to learn about slow door and long exposure!
