25

There is no hardware solution, short of some crazy* arrangement of mirrors to extend the actual optical distance. That's because perspective distortion solely related to distance, but there might be a software one, if you're able to throw a computer at the problem and able to accept some limitations. For a computational approach, see this paper: Perspective-...


17

Distortion is produced by the lens, not the sensor. So the distortion correction you describe is also referred to as lens correction. There are different distortion models (equations). The parameters depend on the specific distortion models used. Different cameras and software may use different distortion models. Camera manufacturers tend to not reveal ...


15

Shoot early in day to avoid heat waves. Or shoot from elevated position.


14

Does anyone know if this software uses the Brown-Conrady model to achieve the lens correction? Yes they do use those very common camera calibration coefficients. I added some copyable text versions of the formulas to the following quote: Adobe Camera Model Geometric Distortion Model for Rectilinear Lenses xd = (1 + k1*r^2 + k2*r^4 + k3*r^6)*x ...


13

There are three major considerations that make lenses with less distortion, vignetting, or any other "correctable" aberrations more desirable for many photographers than correcting later in post. Time constraints. While it is true that you can use postprocessing applications to correct for distortion, vignetting, and other aberrations, doing so ...


13

Those have completely different impact. Vignetting Vignetting is a darkening of the corners or edges which depends on aperture and focal-length. In order to correct this in software, pixels around the edge must be gradually lightened in proportion to the light fall off: Slight vignetting is hard to notice unless the background is known to be uniform. Thus,...


13

If you simply want visual examples with commonly available lenses and resolutions the webpage: "Guide to Identifying or Recognizing a Face: Resolution, Focal length, and Megapixels" has a number of examples. Axis Communications has what they call a Pixel Density Model: Examples of maximum distances for identification (500 px/m or 80 pixels/face). The Axis ...


12

It's not so much a defect as a property of wide-angle lenses: they distort things on the sides. This distortion is why they are not recommended for portraiture. Of course, the very same distortion is what gives wide-angle its power, making it great for photographing interiors (making them look larger) or when going for an "artsy" effect.


12

Drone do not curve images. Camera lenses do. You can mount different types of cameras or lenses on a drone but many models now have their own built-in camera which usually incorporates a small fisheye lens. This allows them to have a huge field of view and so they do not need to fly very high to see an entire scene.


12

Unlike most other digital cameras, Panasonic micro four-thirds cameras record lens correction information (distortion and CA, iirc) into the EXIF information of their RAW files (and will bake in the correction if you shoot JPEG). Some applications recognize and apply this correction information, some don't. That's why you're seeing different results, ...


12

Perspective is determined by the position of the camera relative to the scene. When a camera position produces a perspective that makes an object or scene look different than we might expect it to look we call that perspective distortion. All of the other distortions listed are a result of the way lenses bend light as the light passes through them. They are ...


12

Classic standards have always been more like 2 meters Minimum distance for portraits. 3 meters is common in professional studios, for even better perspective. Too little distance (like 1 meter) will exaggerate and enlarge closer features like noses. This distortion will not please the subjects. The standard notions are the 105 mm lens is good for head and ...


10

You can correct lens distortion in post, but you do so at the expense of some of that higher resolution. Roger Cicala of LensRentals.com says in a blog post where he tests the uncorrected and post corrected resolution of an EF 24-105mm f/4 L lens at 24mm: But when someone wants to argue that they buy a lens with high distortion because it has higher ...


9

The stars aren't black; the spaces between them are. (or rather, dark blue) The brighter bits between that dark ones are the defocussed stars. Due to the defocussing, they have grown in apparent size, overwhelming the blue background. Think of a real star in the sky which is really just a point, but viewed through a defocussed lens appears as a disc.


9

This distortion is due to the sun shining on the water. The sun's heat warms the surface causing warm air to rise. Likely some water vapor mixed in. What happens is, different layers of different density air alters the path of the light rays from the principle subject. There is little you can do to mitigate. A UV filter or polarizing filter might provide a ...


8

Micro Four Thirds (MFT) is a vendor-neutral platform that standardizes the information communicated between camera and lens. Lenses can inform the attached camera body some of their chromatic aberration (CA), lens distortion, and and vignetting characteristics. This allows for an MFT body to do in-camera lens corrections. Aside from the obvious reasons of ...


7

There are several problems transforming the curvilinear perspective of the wide angle GoPro lens to a rectilinear one. The transformation stretches the image in certain areas and compresses it in others. This lowers the image quality as new pixels are created as approximations and interpolations from the information in the original image. There is also a ...


7

from http://wiki.panotools.org/Lens_correction_model The actual lens correction parameters a, b and c which are used to correct for barrel distortion, pincushion distortion and even wavy distortion. The a and c parameters control more complex forms of distortion. In most cases it will be enough to optimize for the b parameter only, which is good at ...


7

The first and third photos exhibit barrel distortion which is normally to be expected at 18mm when using an 18-55mm zoom lens. Software correction can help, but for best results you need software that includes a custom profile of that particular lens on that particular camera. There are also some perspective issues in shots #1 and 3, which are related to the ...


7

This type of distortion in the corners is one of the trade offs for having a rectilinear lens that can render a wide field of view that covers a spherical area into a flat rectangular image. If you want things near the edges of such a wide field of view to appear undistorted, then you need a fisheye lens. But the fisheye lens will not produce a rectangular ...


7

More generally, why is there even a drop-down for me to choose between rectilinear and fisheye, given that it's purely a function of focal length, which is already an input? I must be missing something. Your assumption is incorrect. Rectilinear and fisheye (or curvilinear) lenses are constructed differently, with different mixes of distortions. If someone ...


7

If you take a photo of a FF camera and 75mm DX lens and compare that image with another shot of same subject made by a cropped camera and a 50mm lens what you will see ? But to be able to see the "same subject size" in the pictures, the longer lens must stand back further. So that is a difference in what the lens will see there, at that new location. So ...


7

Unfortunately, as of right now, darktable doesn't have a very good way of doing ad hoc distortion correction for a lens you don't have a lensfun profile for. The following is a dirty hack that may be useful in cases where the barrel distortion at the wide end of a zoom is so strong that even "incorrect" correction might be an improvement... In the lens ...


7

It's a typical result of rectilinear projection with a very wide angle lens. It's compounded by the hand being much closer, relatively, than the face to the camera.


6

Two things common to Wide angle lenses can do this, barrel distortion and perspective distortion. For barrel distortion, when pulling in a very wide amount of information from off axis, light gets distorted based on how extreme of an angle it is coming in at because the lens can't completely correct for how far off the lens axis the light is. On the ...


6

The problem with the outline of the ball not being a circle is not a sign of pincushion or barrel distortion. Indeed let us assume an idealised perfect lens. There is one focal point (the distance of that point from the sensor is the focal length). Now for any point of an object that you photograph, just consider the line through that point and the focal ...


6

There's nothing obviously wrong with the image. You've got a very narrow depth of field, so the grass in the foreground and background is out of focus, but that's not surprising if you were shooting something relatively close at a long focal length. There's some chromatic aberration (red and purple fringing) in the unfocused areas, which also isn't ...


6

The image with barrel distorsion is the actual image recorded by the camera in raw format. The corrected image on top of it is the jpeg that the camera pre-processed (with knowledge that that specific lens has that type of distorsion) and embedded into the raw file. In short, raw processors which don't have a correction profile for your specific lens with ...


Only top voted, non community-wiki answers of a minimum length are eligible