How to break through the limits of photography

Do you like photography? Do you know how to break through the limits of photography? See how the great god synthesizes the depth of field. Let's have a look!

I believe that many people have taken photos like the following, which contain the middle and long-term prospects in the foreground:

When you want to take this kind of photo, you must put the camera close to the foreground and integrate it into the composition. At this time, the problem came.

Even if you reduce the aperture of the lens to a minimum or change the focal length, you can't guarantee that the picture will be clear from the nearest to the farthest.

As we all know, when you lift the camera to shoot, there will be a focus in the viewfinder, and the focal plane of this focus must be the clearest. Then according to the aperture size you use, the sharpness of different focal planes will be different. For example, if you aim at a distant mountain and the aperture is f8, then the foreground must be the clearest, and the foreground close to you will be empty, which is a natural physical phenomenon of the lens. But this is also what we don't want to see. So in order to avoid this situation, only some techniques can be used to overcome it.

And this technology is a big move to break through the lens limit and create infinite depth of field-depth of field synthesis.

(1) Preparation before shooting:

First of all, you should bring a stable tripod, and some slight shaking of the camera will bring trouble to your later assembly. Of course, you need a reliable cable release, which can effectively avoid jitter when you press the shutter. I don't recommend using time-delay shooting instead of cable release. When the light changes rapidly, this two-second delay is likely to make you miss the only opportunity. )

(2) Settings when shooting:

When you decide on the composition, the first step before shooting is to make some settings for the camera.

1. Set the camera to aperture priority shooting mode.

Someone asked why we didn't shoot in the M file, that is, the exposure lock remained unchanged. Isn't it easier to sew later? Although M-file can make the exposure of a series of shooting materials completely consistent, aperture priority can immediately calculate a reasonable exposure parameter according to the ambient light. In some cases where the wind and cloud change suddenly and the light is fleeting, speed is even more needed.

2. Set the photo quality to RAW. In order to keep more details of dark highlights, there is more space in the later stage.

3. Turn the lens from auto focus to manual focus, that is, turn the lens from af to mf. I use Canon, as if Sony Nikon can switch the focus mode on the fuselage.

If your wide-angle lens has anti-shake, be sure to turn off anti-shake.

5. Set the camera metering mode to global metering.

Set aperture

If the wind is very strong when shooting and the foreground light is very dark, it is often necessary to use a larger aperture and high iso, improve the shutter speed and freeze the foreground. If there is almost no wind at the scene and the foreground light is good, you can narrow the aperture a little. The smaller the aperture, the deeper the depth of field, which can reduce the number of shots and improve efficiency.

(3) Operation during shooting:

First, screw the focus ring of the camera lens to the nearest place. There is a small transparent window on the mirror body, which can directly observe the change of lens focal length.

I used Canon 16-35, and this lens, I screwed it to the nearest focal length, 0.28. Then press the shutter to take the first photo. Then twist the lens focus ring to a larger value, and then press the shutter to take a second picture. Next, twist a little in the direction of a larger number, and then take the third picture … until the lens is screwed to infinity to take the last picture.

Don't screw Canon's wide-angle lens to the end. As shown in the above figure, twist it to infinity and come back a little, so that the scale line is just in front of the L-shaped line at infinity, which is infinity. Nikon and Sony's lenses seem infinite if they are screwed directly to the end.

As for the extent of twisting when shooting, it's up to you. If you are conservative, it is the first time to try this technique, and the aperture is relatively large, or you are shooting a very important scene, you can twist a little less and take more photos with different depth of field, which is safer. And if you are bold, or when shooting, the light is sufficient and the aperture is smaller, you can twist it a little. Generally speaking, taking 5 or 6 pictures can basically cover the panoramic depth from the nearest to the farthest.

Tip:

After shooting a set of depth of field, to be on the safe side, I usually do another set of depth of field shooting to ensure foolproof. Because this technology has very high requirements for the early stage, the early stage must be perfect. And pay attention to the exposure of the picture when shooting, because sometimes the light changes very quickly. For example, the sun will be very bright when it suddenly emerges from the clouds, and the sun may be blocked by the clouds in an instant, and then the light will be very dark. At this time, it is necessary to quickly add and subtract exposure compensation to make the exposure of a group of pictures synthesized by depth of field basically the same.

(4) Next steps:

1. Filter

Firstly, several groups of photos synthesized by depth of field are imported into lightroom for filtering. I will repeat the comparison and enlarge the details to make sure to keep one of the next groups. The selected photo is the final material of our depth of field synthesis.

Then zoom in and look at each picture in the left group of photos, and compare the focus position and clear area of each photo. Because when rotating the zoom ring to shoot, there will always be some clear areas that are similar and overlapping due to the magnitude of the torsion. This step is to delete those pictures whose focal planes overlap more in a group of photos, and finally leave only those pictures whose focal planes are basically complementary.

This step can not only reduce the running time of the computer when stitching, but more significantly, if there is wind when shooting, the flowers and plants in the foreground will definitely shift. If multiple pieces are spliced together, it will interfere with the algorithm of computer stitching and cause dislocation and ghosting.

The writer above is Shi, a member of Polar Shadow Axe. The shooting conditions are what I call windy weather. The wind is very strong and the flowers and plants in the foreground are seriously displaced. Below I intercepted his description at the bottom of the work, so that you can appreciate the difficulty of shooting and synthesizing:

Taking this photo may be the most challenging of all my photographic experiences. I heard that wild flowers are blooming along the Columbia River at the junction of Washington State and Oregon, so I drove to Columbia Hills, a famous wild flower land, where the advantage is close to water. I was hit by a strong wind of 35 miles an hour when I stepped on the spot before. I had to give up and shoot elsewhere according to the situation. On Monday morning, the weather forecast predicted that there would be a breeze with a speed of 9 miles per hour, and it would arrive at the shooting point with anticipation one hour before sunrise. As soon as I opened the door, the door was instantly blown back by the rapid wind and almost hit my hand. Walking into the field, I found that the wind was not weaker than when I stepped on it. Under the strong wind, most of the yellow wild flowers were bent and became a side-to-side Mt Hood posture. The wind continued to howl and rarely stopped for a moment. This has caused great difficulty in composition-because it is difficult to judge the position and shape of flowers when they are still. Holding the camera, I kept wandering among the flowers, trying to finish the composition of the belt of venus scene before the sun directly hit the ground. When the composition was finalized, I began to watch the repeated snapshots of the depth of field synthesis for half an hour. ISO exploded from 800 to 4000 to "nail" the swaying flowers and plants. Stacking a complete set of depth of field requires moving the focal plane continuously for 3-4 times. However, the occasional wind breathing only gave me the most 1-2 capture opportunity, which was not enough to complete a whole group of shooting. What is more difficult is that there will be obvious displacement of flowers and plants between the two pieces. Therefore, I can only hope that I can catch more groups and select enough materials from them to complete the depth of field synthesis. I wasn't completely sure that I could finish watching it until I went home and began to choose films in the later stage. Thankfully, after two days of continuous processing, the scene in my mind finally appeared completely.

adjust

Make basic adjustments to the photos in lightroom, and lay a good foundation for the subsequent stitching in ps. Usually correct the exposure, make a basic color matching for the photo, reduce the noise and sharpen it. After adjusting the photos, you need to apply this effect to all the pictures in the group.

Select all the pictures, click Sync Settings, check all the options, and then click Sync. In this way, all the adjustments of a photo will be copied to all the pictures synchronously, and the effect will be the same.

Tip:

If the light changes quickly when shooting, the exposure of each photo may be different, so you need to adjust each photo separately after synchronization settings.

compound

After completing the basic adjustment of photos in lr, import all the photos into ps.

Select all the pictures, right-click, select Edit in Application in the pop-up window, and then click Open as Layer in photoshop. In this way, all the pictures will be automatically loaded into ps and superimposed on the same canvas as layers.

Then select all layers and click Edit-Auto-Align Layers in the toolbar above ps, so that all layers will be automatically aligned by the software.

This alignment operation is to overcome the respiratory effects of the lens. When we twist the focus ring, the lens will move the floating lens to focus, and the movement of the floating lens will inevitably bring about changes in the optical structure, so the focal length will change. Therefore, although the position of the plane is fixed, the photographed picture will definitely be slightly deformed and displaced, so it is necessary to rely on the powerful alignment function of ps.

After auto-alignment, there is a white edge around the picture, which is the extra pixel when the program stretches the image to match the pixel.

After alignment, whether you want to fuse the pictures together or select all layers, click Edit-Automatically Blend Layers, select stacked images in the pop-up dialog box, and check the seamless tone and color at the same time, then click OK to start automatic blending.

The following figure is the final fused image, and there is a mask next to each layer, which is automatically calculated and generated by the software. This function can calculate and grab the clearest part of each layer, and then fuse it.

Then we merge the layers. If you don't use a tripod when shooting or there is strong wind at the scene, it will cause the displacement and shaking of the elements in the picture. At this time, you can't completely rely on the automatic synthesis of ps software. Before this step of stitching, you need to manually adjust the mask of each layer and brush the clean part with a brush. This process is more technical and time-consuming.

After merging the layers, use the cropping tool to cut the blank and blurred parts around the picture. Therefore, when shooting, try to leave room for composition and post-editing.

This is the last cut photo, and we can see that the picture from the nearest to the farthest is very clear and sharp.

The following are the pictures taken by me and the members of the polar shadow axe with depth-of-field synthesis technology: