How to use door B in d700

Simply put, set the shutter speed to m, and then adjust the shutter speed. After the shutter speed reaches 30 seconds, adjust the shutter speed to the so-called B-door, that is, the photographer controls the speed from pressing the shutter to releasing the shutter. The following is the explanation of door B found on the Internet.

"B-door" is a bit primitive today when the camera is developing in the direction of super automation! This is an exposure method completely controlled by the photographer, and it is also a process of personal creation. The original meaning of "B" in the dictionary is light bulb, which refers to a spherical pneumatic shutter operated by hand or flash.

Flash used for exposure. However, a slightly creative photographer thinks that "B" is actually synonymous with infinity. "B-door" is different from other shutter speeds. Photographers can use it to control the shutter switch at any time except 1 second, thus entering the fantasy world. When you enter the field of "Brl", you can see strange scenes other than traditional photos, such as the track of stars in the night sky, rainbow-like light and shadow, street scenes without people and shining sky ... The basic requirements for using B-door photography are a camera with a B-door that can open the shutter for a long time, a relatively stable tripod and manual cable release. It is best to have an ultra-sensitive hand-held exposure meter when shooting, because many cameras have built-in exposure meters that can't accurately measure the amount of light for possible dark scenes. Photographers with experience in B-door photography often suggest grading exposure as much as possible when shooting, because it can make the effect more varied. They also admit that although the most successful Brl exposure often comes from inspiration, a more sensitive exposure meter can at least provide a basis for graded exposure. Photographers who are good at shooting night scenes point out that one of the best ways to prevent camera shake when using B door to end long exposure is to cover the lens before releasing the shutter. There is a better way to lean against the lens with a piece of black cardboard instead of the ordinary lens cover. Another advantage of this method is that you can change the focal length or aperture during exposure. If the camera shakes occasionally during calibration, it is necessary to ensure that the camera has stopped shaking before continuing exposure, which is especially important for shooting with a long focal length lens.

Failure problem of changing law

When using B-door for long exposure, the problem that is easy to appear is the so-called "reciprocity law failure" that photographers often say. This usually happens when exposed to color film for one second or more. Fundamentally speaking, long exposure will change the color balance of the film, and this phenomenon is often unpredictable by photographers. Generally speaking, there is no simple way to solve the problem of the invalidation of reciprocity law, so that every shot can be accurately exposed. David Williams, a British photographer, put forward a simple method, that is, "take more photos with longer exposure time on the basis of the calculated exposure." Williams pointed out that for long exposure, it is necessary to record the exposure time and aperture used by each photo. In addition, various exposure indexes can be used for shooting to make up for the deficiency caused by the failure of reciprocity law. One way is to increase the total exposure. For the exposure of 1-9 seconds, increase the aperture of 1/2-L; For the exposure of 10-99 seconds, increase the aperture of 1-2; When the exposure time exceeds 100 second, the aperture increases by 2-3 steps. An indicator like this means that in general, it can't be regarded as a static thing, especially with different films, depending on the specific situation.