How to create a perfect long exposure in one stroke

Lead: Do friends often see many star orbits and light paintings recently? Under the magic of long exposure, the running water becomes silky smooth; Can record the light graffiti, car tracks, star tracks and other light transformation tracks, making the picture more magical; The colorful lights in the night become brighter. Long-exposure photography has long been sought after by photographers, especially in the field of landscape photography, and one of the most important reasons is that: as far as standard exposure is concerned, the scenes presented by long-exposure photos may be softer and more harmonious, and the pictures that may look ordinary to the naked eye will become like fairyland under long exposure, which will bring great surprises to our vision. Due to the rapid development of digital cameras, we can now avoid a lot of noise caused by overheating of sensors that are really exposed for a long time. In addition, the improvement of the quality of the medium gray density filter enables us to choose black and white shooting without reducing its clarity.

How to create a perfect long exposure if you love long exposure photography and want to maximize the exposure time, then the long exposure picture stack must be to your liking. Picture stacking is to take a series of images first (usually each image can be exposed for at least 30 seconds to achieve the final goal), and then stack these photos together to get the same effect as a single long exposure photo; Because the exposure time of a single photo is equal to (or almost equal to) the sum of the exposure times of multiple photos. Although other methods also have their advantages, this technology is usually recommended as the most useful method in landscape photography, especially when you need to expose for a few minutes to get the best photos.

Advantages of long exposure stack

1, increasing the total exposure time.

Step 2 reduce noise

Step 3 reduce dark corners

4. Minimize the risk of wasting time and memory

5. The long exposure effect can be decided by yourself.

Disadvantages of long exposure stack

1, some late skills are needed in the process of stacking.

If you are a purist, then you may not be interested in this technology.

3. If your photos need to take part in some photography competitions, the competition rules do not allow photographers to use such skills.

4. There are some overlapping marks after the late effect comes out.

When is the best time to use this technology?

1, you attach great importance to exposure time when shooting.

2. When your camera sensor is overheated, it will produce a lot of noise, which will affect the image quality.

3. If you are not sure about the final effect of long exposure when shooting. Since this technique is based on the sum of several short exposures, you can easily decide the final exposure time.

4. When shooting in bad environment or weather, you can unlock this skill to minimize the risk caused by too long exposure time.

5. If you don't want to miss the best moment in the rapidly changing light environment, the long exposure stack is undoubtedly the best choice (the best moment only lasts for a few seconds, and if you make a long exposure for a few minutes, this moment is likely to pass you by).

Step 1: Equipment

The equipment needed for this technique is exactly the same as that needed for long exposure photography, so if you are very familiar with long exposure photography, I believe you already have all the equipment. If you are a novice, here is a short list for your reference:

1, digital camera (which can be exposed for a long time)+lens (which can be fitted with a medium gray filter)

2, tripod! Tripod! Tripod! Say the important things three times! A stable tripod is a necessary condition for taking high-quality long-exposure photos)

3. Shutter remote control (unnecessary, but recommended)

4, medium gray density filter (we know that if you want to shoot long-exposure works during the day, even if the aperture and ISO parameters are adjusted to a minimum, the photos will be overexposed. At this time, it is time for the dimming filter to play a huge role. )

Step 2: Make a shooting plan.

We often underestimate the importance of making a photography plan in advance, and always feel that the enemy will block us, but not every time we shoot, we have good luck. If it is said that making a plan before each outdoor shooting will make the photographer have a well-thought-out plan, then the photographer will not only miss the best shooting opportunity, but also make full preparations before it. Don't press the shutter easily without a proper shooting plan. Although there will be many unexpected situations in the process of shooting, planning is very important for shooting good works.

Step 3: shoot.

When you make a shooting plan and arrive at the shooting location, you have to decide the two most important elements in your photography: composition and exposure (in landscape photography, the depth of field should be kept as constant as possible). The form of composition can be made according to your preference, but exposure is complicated due to various factors.

The first thing a landscape photographer needs to do before taking any photos is to determine the exposure time by metering. The final exposure time depends on many factors, such as the size of wind, the movement of clouds, the speed of running water and so on. The question is:? How long should I be exposed? If the light changes suddenly or the wind is strong during shooting, or even the camera or tripod is blown out during exposure, it may be necessary to give up long exposure (so as not to miss the best shooting opportunity and waste shooting). Long exposure stack may help you at this time.

If you want a total exposure of 8 minutes, you can divide the total exposure time into four consecutive times, with two minutes exposure each time, in addition to the direct exposure of a single photo for 8 minutes. You are free to decide the total number of shots. But remember, if you want to overlap pictures, try to reduce the time interval of each shot; Not to mention avoiding moving the tripod or camera (to achieve the same shooting scene). After continuous shooting, you will understand what you need to do in the later stage.

Before you start shooting, you must make sure that your tripod is stable (avoid standing on sand or uneven ground) and that you are in the right focus. Regarding the focus of long exposure photography, it is best to use manual focus; Don't use autofocus again, especially at night or in dark environment; Because in such an environment, autofocus is likely to focus incorrectly and blur the subject that should not be blurred. Of course, you can use autofocus as a reference, and then set the lens or camera to manual focus (MF) to shoot. At the same time, we will choose more M files to shoot, because then you can adjust the aperture, shutter and ISO in time to achieve the desired effect.

After taking a photo, you can check whether the exposure of the picture is correct by looking at the histogram to ensure that each work is exposed correctly.

? Take the above three pictures as an example. This is three photos with exposure of 4 seconds (usually at least 30 seconds for each picture) and 3X4 seconds, and the total after superposition is 12 seconds.

Step 4: Image superposition.

You can browse all the pictures manually at home or in your favorite cafe, and choose the photos you want to overlay. We will post-stack in PS (basically all versions support this function). You can also choose other software, as long as the software can operate the layer. There are two different methods of superimposing images in PS, and the goal is to combine them into a simulated long exposure. These two methods are:

1. Load photos on the stack.

2, manual superposition

In most cases, we choose the first semi-automatic method, just click File >; Scripts > loading files into the stack is more convenient. We choose the photos we need in the dialog box and check them? Try to align the source image automatically? And then what? Create only objects after loading layers? .

When a new file is created, we will click menu >; Smart object > stack mode >; Average value. This will weight all the pictures and embed them into the smart object to present a new image, similar to the result that the sum of a single exposure equals the total time of a long exposure.

The second method is manual, and the rule is to reduce the opacity of each layer (that is, the image taken every time); How much should each picture be reduced? It's not fooling around, and it's not that complicated. The following table is the mathematical rule for adjusting opacity:

The first picture (base map):100% (11)

The second picture: 50%( 1/2)

The third picture: 33%( 1/3)

The fourth picture: 25%( 1/4)

Chapter 5 Pictures: 20%( 1/5)

Chapter VI Pictures: 17%( 1/6)

?

The nth picture 1/N

Superposition result

Step 5: Other later stages

After finishing the image superposition, we can fine-tune other aspects of the photo according to the post-processing of personal habits, such as:

1, cleaning dust spots, stretching, optional image

2. Adjust the dynamic range and add HDR effect.

3, adjust the exposure and contrast

4. Adjust the color temperature and hue

5, according to personal taste to do the final modification and polishing.

6, export works

Summary:

Because this technology is flexible, it is sometimes very practical. In the process of superposition, the quality of the final work has also been significantly improved. Obviously, noise can be reduced by superimposing images. For example, if you stack four photos, you will find that the noise in the static part of the photo is reduced by half, which is a great achievement for the underexposed part. The use of this technology is very common in satellite orbit photography or other fields that are not suitable for increasing the exposure time of a single frame.