How to choose the thinning mirror? What gear is used under what circumstances?

The basic function of subtractor is to reduce the amount of light entering the lens, thus increasing the exposure time. In some too bright scenes, that is, using the fastest shutter and the smallest aperture will still cause overexposure. If the nd filter can be used correctly, the normal exposure effect can be achieved. Theoretically, the filtering function of Nd-reducing mirror is non-selective, and its dimming ability for light with different wavelengths is equal and uniform. That is to say, using ND filter has little effect on color. However, there is always a certain difference between theory and practice. In practice, it is found that different neodymium mirrors, especially those with large dimming amount, will still produce some chromatic aberration. In addition, when shooting with a wide-angle lens, the depth ND lens will bring some so-called "vignetting" phenomenon to the four corners and periphery of PP ... The way to avoid it is to sacrifice some wide-angle lenses, such as 17-40MM lens; If you add a large-downshifted ND mirror, it is best to use only about 20MM, so there will generally be no "vignetting".

PRO ND 2 professional reducing mirror

PRO ND is the top-grade density reducer in the color filter market, and the filter has perfect color correction performance through metal evaporation process. PRO ND2 cuts the aperture by 1 or 50% of the light enters the camera.

Professional reducing mirror PRO ND 4

PRO ND is the highest density reducer in the color filter market. Through metal evaporation, it is made into a filter with perfect color correction performance. PRO NO4 can reduce the aperture by 2 levels or 75% of the light enters the camera.

Professional reducing mirror PRO ND 8

PRO ND is the highest density reducer in the color filter market, and the metal evaporation process makes them have perfect color correction performance. PRO ND8 cuts the aperture by 3 levels or 87.5% of the light enters the camera.

ND400 variable diameter mirror MC ND400

It can reduce the intensity of 9 levels, so that the light entering the camera is equivalent to 1/500 of the original brightness, which is suitable for long-term exposure or shooting the sun during the day.

When editing this paragraph, use the reducing mirror. In most photography situations, strong light is often needed to supplement the light, which can not only reduce the influence of hand vibration, but also be a necessary condition for capturing instantaneous things. But sometimes when shooting a dynamic theme, we hope to have a dynamic effect in the photo to express the actual situation at that time. At this time, a slow shutter must be used, and overexposure is often the inevitable result. The medium gray mirror is designed to meet such shooting needs. The following three commonly used mirror reduction environments and shooting sites are for reference only.

Use strong light to shoot.

For consumer digital cameras, there are many restrictions on the range of aperture and shutter due to market considerations. As for the shutter, the shortest shutter is mostly in11000s ~1/2000s, and the small aperture is about F 1 1. If the shutter speed is not enough, overexposure may occur under strong light, especially at the seaside in summer.

Take a picture of foggy running water.

Using a faster shutter can concentrate the action, and a slower shutter can record the trajectory of the action. When shooting running water during the day, if you want to shoot a picture with dynamic effect, you can choose landscape mode in the scene mode. Using a digital camera with manual function (M-mode), it is more likely to use aperture priority (AV or A) to set a small aperture for shooting, and the shutter speed will slow down. If the user directly sets the shutter priority (T or TV) or full manual mode (M), it is necessary to pay attention to whether the aperture reaches the minimum limit when setting the slow shutter. If the minimum aperture limit is exceeded, the captured image will be overexposed.

In fact, it is often found that even if the minimum aperture is set, it is quite difficult to shoot beautiful running water from the perspective of daytime brightness. At this time, we can use the reducing mirror to reduce the light, effectively reduce the shutter speed, and it will be easier to shoot dynamic images. It is especially recommended to use a tripod or put it in a stable place when shooting such subjects to avoid the static objects in the picture being blurred by vibration.

Application of Night Scene Shooting

Night shooting is believed to be a big challenge of photography technology. Digital cameras can preview the shooting results in real time. For novices, it is much more convenient for night shooting in cities with high failure rate besides shooting in the orbit for a few minutes or even hours. Even so, when using consumer digital cameras to photograph the flow direction of car tracks, it is often found that only one car track can be photographed, but not the whole line track.

The light damage in cities is quite serious. When using a consumer digital camera, because its small aperture can not effectively reduce the exposure, the shutter speed will be limited, so it can not be exposed for a long time, otherwise it will be overexposed. If we use a small aperture with a variable diameter mirror, it will not be difficult to shoot beautiful rails.

The shooting method is to fix the camera on a tripod or a stable place, set the scene mode to night scene mode, or set the aperture priority (AV)/ manual mode (M) to small aperture for overall composition. After the composition is completed, add a medium gray mirror. At this time, users using M mode need to slow down the shutter until the exposure compensation value becomes "0".

Using the timed self-timer function to shoot can avoid image jitter caused by the action of pressing the shutter by hand. In addition, you can use exposure compensation to take more photos of different exposure value. I believe you can put your beautiful night scene into the photo album.

Application in rainy days

Subtractor can also "resist" a lot of scattered light, which can improve the color saturation of the picture when shooting in rainy days, and the reduction of scattered light can make the picture look more transparent. However, the use of medium gray mirror will reduce the shutter speed by two steps, which may lead to image blur in poor light environment.

ND4 and ND8 are two levels. The larger the value, the lower the transmittance.

ND2 dimming 1 gear

ND4 dimming second gear

How to use ND8 dimming third-gear dimmer? Adding a reducing mirror in front of the camera makes it dark and unclear. The exposure parameters in AV mode are often inaccurate, and most of them are underexposed. How much compensation is appropriate? Different shots are different. What should I do? ? After repeated practice, two steps are the best. ? Step 1: In AV mode, do composition, focus, measure light, record shutter speed, and adjust the focus button from AF to MF (focus lock); ? Step 2, add a reducing mirror, switch to manual mode (M-range) and reset the parameters. Of course, the sensitivity and aperture should be consistent with the AV mode just now, and the key is to set the shutter speed. I have figured out the shutter speed setting after adding a reducing mirror after many twists and turns. You don't need to walk a few steps. In fact, the value after ND on the top of the pressure reducer is the most useful. Measure a shutter speed before adding a reduction lens, and after adding a reduction lens, multiply the shutter speed just measured by the value after nd on the reduction lens. ? For example, in AV mode, the exposure speed before adding the filter is 1/200 seconds, and the exposure speed with the filter of ND8 is adjusted to 1/200×8= 1/25 seconds. ( 1/200, 1/ 100, 1/50, 1/25; Three steps are reduced, that is, 2 3 = 8, that's how Nd8 is dropped) and the lens of ND400 is added, and the exposure speed is adjusted to 1/200×400=2 seconds; (that is, 2 8 = 256, 2 9 = 5 12, so ND400 is equivalent to reducing 8-9 steps, and 400 is closer to 5 1 2, which can be regarded as 9 steps, but actually it is less than 9 steps), and the lens of ND 1000 is used for exposure. (i.e.

2 10 = 1024, so ND 1000 is equivalent to a reduction of 10)? ........？ If you add polarizers or other filters, there is a product relationship between them and the subtracter. ? For example, my polarizer, measured approximately equivalent to ND2.5. If a polarizer and ND400 attenuator are installed in front of the camera, it is equivalent to ND400×2.5=ND 1000. Ten steps down and so on. It should be noted that when using the subtractor, it is best not to leave the eyepiece when metering and shooting. If you leave, the light leakage of the visual mirror will cause uneven exposure.