Shulou(Shulou.com)11/24 Report--

Photo deformation is a very common problem, which can be encountered in all kinds of photography, such as portrait photography, landscape photography, still life photography and so on.

Perspective distortion, lens distortion. The positive one becomes crooked, the square one becomes round, the straight one becomes curved.

Positive use of this deformation, we can get the special effects we want, such as low-angle upside shooting can make the character higher, legs appear longer, such as the fisheye lens spherical effect, loved by many photographers.

But in most cases, the impact of this deformation is negative, we need to eliminate this deformation and restore the original appearance of the photo.

1. Lens distortion light enters the camera through the lens, which is a very fine and complex process. When the light passes through the lens, there will be loss and refraction, so each optical lens will have a certain distortion.

In the photos of "pillow distortion" and "barrel distortion", the pillow distortion usually occurs in the telephoto lens, or at the telephoto end of the zoom lens, the original straight line of the object shrinks to the middle, like a pillow. Barrel distortion usually occurs at the wide-angle end, or the wide-angle end of the zoom lens, and the straight line at the edge of the picture expands outward to form a barrel.

Normal objects, pillow distortion, barrel distortion are not easy to detect, even some later software can not recognize, if you think it does not affect the look and feel of the photo, you can ignore it. Think of the photo as a flat piece of paper, barrel distortion is like sticking paper to a ball, pillow distortion is like holding paper close to a bowl.

Solution one the first solution is the most recommended. If you use RAW format when taking a photo, open it with ps's ACR, or open it with LR, check "enable Lens profile" and select the corresponding camera and lens model.

The following photo, the first of which is the original image straight out of the camera, was taken with a wide-angle lens of 28mm, showing a barrel distortion. The second is the adjusted photo, the configuration file of this lens is selected, and the computer automatically adjusts it.

If you do not open it with ACR, or if you have taken a photo in jpg format, you can also select automatic correction in the Lens Correction filter and check the corresponding camera and lens.

In addition to correcting changes in shape, you can also correct chromatic aberration and halo.

Solution 2 the second method is to use common correction methods, such as manual correction in ACR, and manual correction in jpg format to adjust the distortion of the photo.

You can also choose a custom method in the lens correction filter to manually adjust the geometric distortion of the photo.

In addition to correcting shape changes, chromatic aberration and halo can also be corrected.

2. Perspective deformation is also a very common phenomenon, because it is difficult for you to "flatten the camera and face the middle". Even if it is really flat, it is difficult to solve the problem of height. When shooting tall buildings, if you do not use a special lens, it must be wide at the bottom and narrow at the top.

Photos to be horizontal and vertical, some photos are not horizontal and vertical, this is also a common problem, especially when buildings and trees appear in the picture, if the vertical is crooked, it looks very awkward.

(the building on the far right is somewhat inclined)

The first solution is to use the Transform tool in ps's ACR, the first one is automatic mode, the second one only corrects the horizontal direction, the third one only corrects the vertical direction, the vertical line becomes vertical, the last one needs to animate four lines by yourself, and these four lines will become horizontal and vertical.

The second solution uses the custom mode in the lens correction filter, which provides a variety of adjustment functions, including vertical perspective, horizontal perspective and so on.

The third solution is to choose the "ruler tool" in ps, draw a line and click "straighten the layer". If you draw a vertical line, it will become vertical after pulling, and if you draw a horizontal line, it will become horizontal.

This tool is only suitable for simply adjusting the rotation angle of the picture, not for complex perspective deformation.

3. Ultra-wide-angle / panoramic deformation when using superlight lenses, especially when panoramic pickup, the original straight line often bends, so you can use a filter in ps to "adaptive wide-angle".

After opening the filter, select the first tool in the upper left corner and draw a line along the curved part in the photo. The drawn line will automatically stick to the curved part, and after the drawing, the curved part will automatically straighten. If it's not obvious, draw a few more.

This article is from the official account of Wechat: photography Research Society (ID:shoujiPhotography), by Zhang Xiaozhang.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.