Post-processing of long exposure shooting star orbit

Lead: My first long exposure was to record traffic with a slow door. Later, I recorded the state of water, the vastness of the sky, the orbit of the stars all night, and the lightning in bad weather? In my own experience, I learned time-lapse photography and began to record scenes by dynamic means. While discovering its dynamic beauty, I also learned to create long-exposure films through time-lapse photography and post-synthesis, and at the same time made up for some shortcomings of long exposure. Below I will share some of my own experiences with you.

Advantages of post-processing and post-exposure synthesis of long-exposure shooting satellite orbit

Watch two films first. The first one is a long-time exposure photo of the star orbit released directly by Gate b+ cable at first.

The specific parameters in the above picture are: Nikon D600, 17mm, F8 ISO 100, 3429.7s, the exposure time is nearly 58min, and the starry sky trajectory is recorded for nearly one hour. But it is not difficult to see that long exposure brings more noise in the picture. Many film friends who know about long exposure should know what kind of damage such long exposure will cause to digital cameras. The noise in the picture is due to the long exposure time, and there is thermal noise, which affects the image quality.

The other one is a photo of star orbit and lightning synthesized by multiple lenses in my early and late stages.

The specific parameters of this drawing are: interval shooting, Nikon D600, 35mm, F3.5, ISO 500, 30s, interval shooting time of 30s, * * * shooting 160, and total shooting time of 80min. As you can see, the noise in the film is well controlled and the details are well recorded. The orbit in the air is the same as that recorded by normal long-time exposure.

Let's look at another picture, which is still synthesized later, but the traces left by a satellite-like movement in the picture are intermittent and not connected, which is the middle breakpoint caused by the inconsistency between the interval shooting time and the exposure time. Through my explanation, I think everyone should know what I mean by long exposure post-synthesis.

One step later

There are many softwares available for post-synthesis. Here I recommend a relatively simple software, Startrails, which is also very convenient to use. After downloading and installing the software, the following dialog box will pop up when we run the dual computer. Let's choose the operating language, choose English, and then click OK.

Then in the open software interface, we can see that the operation of the software is only a few buttons in the upper left corner. The first is to add pictures, that is, to add photos to the file on the left; The second is to select the foreground image, that is, to use a picture at the end of synthesis to restore the overexposed details in the photo; The third is known to all, in order to preserve; The fourth one, I haven't used it, I don't know what's the use, o (? _? )O ~； The fourth button is the synthesis button, click to start synthesis; The fifth is a synthetic short film.

After understanding the software, you have to process the photos, click the Open Picture button and select all the photos to be synthesized. If you need to fill in the foreground details, continue to click the second button to add photos, and then click the fifth button, just like the software icon, to enter the synthesis setting interface.

As shown above, there are two options. Select the second option, click OK directly, and the software will start to automatically synthesize pictures. If the first option is selected, the following additional options will be highlighted, such as selecting the option in the red box below, that is, opening the option of storing the photos at that time for each Zhang Hecheng photo during the process of synthesizing photos, where Path is the location where the photos are stored, and Filename is the naming rule and image format of the file name.

In the process of automatically synthesizing pictures by software, the progress of synthesis will be displayed at the bottom of the software. If you need to stop halfway, press ESC. After the synthesis is completed, click the Save button in the upper left corner to save the last picture, and the whole synthesis process is completed.

As mentioned above, we simply completed a post-synthesis long-exposure photo, that is, the photo of the coexistence of the star track and lightning seen at the beginning of the article. Putting the starry sky before dark and the lightning after dark in one picture, this is exactly the different landscape photos that long-exposure can bring to everyone, and we also got long-exposure photos through another way, that is, time-lapse photography. Can be said to kill two birds with one stone, why not?

Pay attention to key points

At the end of the article, I want to tell you that no matter how good the later stage is, it can't make up for too many shortcomings in the early stage, so before this tutorial, we must first have a stable tripod and time-lapse photography skills that can grasp normal exposure. Only in this perfect early stage can we achieve unexpected results in the later stage. Here I would like to add a few points for attention:

When taking pictures, you should consider the later stage. The difference between exposure time and interval time should not exceed 5s, otherwise the film synthesized in the later stage will be discontinuous. If shooting the trajectory of a meteor, this method may not be able to shoot continuously. Theoretically, the exposure time is equal to the interval time, but I tried.

This post-synthesis method can also be used to take pictures with strong foreground light. Because the normal long exposure will overexpose the foreground, and the time is shorter than that of a single exposure, so we can save more details in the later synthesis.

One more thing, I want to tell you here, that is, in the process of synthesis, I mentioned that there is a storage method, and every time a photo is superimposed in the process of synthesis, one more photo will be stored. Careful film friends may ask what is the use of such steps? Here, I upload a dynamic map, please consider it yourself.