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-...


20

The lens correction software may be able to counter lens distortion and chromatic aberration distortion. Also perhaps it can counter poor contrast to some degree. But a good lens has more to offer: Sharper image. The lens correction cannot restore image detail lost due to an unsharp lens. Aperture. Good quality lenses typically have a larger aperture. You ...


18

The terms are fisheye (circular distortion) and rectilinear (straight edges). Fisheye lenses are often unfairly branded as "special effect" lenses by some photographers, due to their near ubiquitous use in skateboarding magazines in the 90s, and the ease at which you can create unusual images when trained on nearly any subject. However fisheyes have sever ...


17

I think it's more correct to say that Lightroom's lens profiles can make any lens "better." Bad lenses are still bad, good lenses are still good. The corrections Lightroom can make simply improve some aspects of image quality. Making the leap of taking a poor lens and making it good is far outside of what LR can do.


16

The two types of lenses you refer to are: Rectilinear - lenses which produce straight horizontals and verticals across the image Fisheye - lenses with circular distortion Rectilinear lenses produce more 'natural' looking images but tend to stretch features towards the edges of the frame, so some subjects, e.g. faces, look odd. But they work well for ...


15

These are known as Chromatic Aberrations or Colour Fringing. These predominantly occur around areas with high contrast such as sharp edges in photographs or around the white water bottle and dark background in your case. A wider apeture can affect the lenses sensitivity to aberrations although certain lenses can see this "effect" vary depending on focal ...


15

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


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 takes time....


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

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 ...


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

It's very difficult to correct by hand, but very very easy for a computer to correct, given a formula for how the distortion behaves. The reason the Photozone review states that this distortion is difficult to detect, is that most software only offers very simple correction based on radially symmetric distortions based on simple formulas. You can usually ...


9

I think the distortion you are seeing is not caused by the lens, I think it's just perspective distortion. The Canon 50mm f/1.8 has a DXOmark distortion rating of 0.2% and if you look at the actual measurements, especially the grid you will see that the distortion is very low - too low to notice in a normal picture - I don't know about the other cameras you ...


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

Actually to avoid distortion the opposite of what you said holds true. Move faces or features you don't want to distort such as fingers away from the edge of the frame Keep the lens parallel to the subject if at all possible Step back and shoot, planning to crop to the desired framing later Consider using the distortion to your advantage for "fun" shots; ...


8

This effect is called fisheye effect You can either get this effect by using a fisheye lens or using photoshop. Try googling fisheye effect photoshop. I found there great tutorials there. http://www.marcofolio.net/photoshop/create_a_fish_eye_lens_effect_in_photoshop.html http://blog.lorrifreedman.com/index.php/2009/04/10/how-to-create-a-fisheye-lens-effect-...


7

Does sensor size affect lens distortion? Short answer: Yes. The reason is only because most if not all distortion happens on the edges of the lens glass. Using a cropped sensor is indeed like printing off a 8x10 picture and then cutting out the 4x6. and therefore by trimming the edges you will most likely get rid of some of the distortion. Just to ...


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

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

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 ...


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