glasses

Glasses                                             
by Meysam                

Submit your Photo
Hall of Fame


Please participate in Meta
and help us grow.

Hot answers tagged

13

There are two 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. ...


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

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. ...


11

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 + ...


8

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.


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 ...


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 ...


5

No, these are unrelated. Distortion removal is a 2D mapping which moves pixels to remove barrel and pincushion distortion. Parallax correction requires multiple images or depth information for each pixel and is performed by completely different software algorithms.


4

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 ...


4

"Wide angle lens" is the right term (see What is an ultra-wide lens? for discussion of the terminology), but the thing is that it's not the wide angle itself that causes distortion. It's being really close to your subject and then projecting that onto a flat plane (like, a photograph). If you need to use a lens wider than the 18mm at the wide end from your ...


4

Do portrait photographers ever use wide or ultra-wide angle lenses as a main lens for children portraiture, or are long focal lengths the better choice? It is highly unlikely that any portrait photographer would use a wide or ultra-wide angle lens as their main lens. Of course it is possible but far from typical. In the particular case of kids, ...


3

I can't speak specifically about LR, but many raw processing applications don't use one of several generic mathematical models (such as Brown-Conrady) that are based on an assumption of rotational symmetry at all if the lens used is a fairly popular one. Instead they use a calibrated correction profile to correct for the measured distortion of the lens at ...


3

You don't need a new lens. Sure, it would be nice to have one. And possibly the EF-S 24mm f/2.8 STM will fit your low-budget requirements while giving you a wider angle of view and remaining a fast prime. But. You don't need it. You have an EF-S 18-55 kit lens, and this will work just fine for you, provided you try a few other things. Granted, the 18-55 ...


3

With the problem you have, in my opinion, it's not necessary to use a wider lens, but first to learn to use what you have. 1) Learn to use the zoom lens you already have. The other users already told you that you probably have a 18-55mm lens. Move the big barrel. @inkista it does provide a wider frame. I just don't like to use the 18-55 indoors (unless ...


3

As always in photography (and most other arts), rules are generally accepted, but they are ment to be broken if it fits your cause. To answer specifically to the question about children photography: what you describe is not completely wrong and can be applied in the sense you would want to. You can find some examples in the following link. From the second ...


3

The model specifies a mapping from an ideal picture on a rectangular grid where the scene is projected in a rectilinear way to a distorted picture on another rectangular grid. It tells you where the pixels that should have appeared at some coordinate (x,y) can be found in the distorted image that you actually have. The problem is then that the gray values ...


2

You can do it in the GoPro software: https://gopro.com/support/articles/how-can-i-remove-the-distortion-fisheye-effect-in-gopro-studio


2

There's your problem I cannot obtain any mathematical description of the surface to be covered. A software capable of doing that distortion needs that mathematical description. It's unclear why you claim that you are unable obtain such description. There are two solutions I can think of: Take the high tech approach and find a 3D scanning service ...


2

There is a Nikon support article here explaining it: What is distortion control? It will correct distortion in supported Nikon lenses and apply the correction to your JPG files. If you are shooting in RAW format, you would need to correct for distortion in your editing software, which is easy to do. It's up to you if you want to correct distortion, as ...


2

The unflattering faces due to perspective is from being way too close. The nose is significantly closer than the ears. The left ear and right cheek are seen from different angles. That is unlike how faces are normally seen. back up. Don't take a picture from closer than you would normally view someone. The size distortions are easily corrected. The ...


2

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 ...


2

One reason is that when you correct for lens distortion you end up with a non-rectangular image. Usually it will be cropped to roughly the largest rectangular area within the non-rectangular image. This means that your image no longer includes everything you saw on the screen when you took the picture. Users generally don't like that. In your picture above, ...


2

We desire a faithful image. We image a rectangle with the same aspect ratio as our camera’s senor/film frame. If we image at unity (life-size) we expect the image of the rectangle to kiss-off at the corners of the image area. With barrel distortion the image will under spill. With pincushion distortion, the image will over spill. The delta  (valuable ...


2

Usually it's focal length that is the key consideration for portraiture, at least in terms of making the subject look "good". (I use the term loosely; good is subjective, but let's assume people don't necessarily want to see representations of themselves with huge chins and noses.) You don't mention the focal length of the lens you are using, or the ...


2

It sounds to me like you're looking for a wide angle lens. The kit lens that came with your camera is probably a 18-55 mm lens. If you're able to fit a tree in your house then you won't need to go any wider than that. As for the distortions, every lens will cause distortion to some degree when the picture is translated from the curved glass to a flat ...


2

I had the same problem with the EF 75-300 lens. I found out that the optics in the glass is made poorly and has a really bad drop off around the edges and when its out of focus the poor contrast on the images. I sold the lens for almost the price I paid for it and saved up for the EF 70-200 f2.8 II USM. Even the EF 70-200 f4 hands down better. The Price ...


2

What you're seeing is know as bad bokeh. What's bokeh? It's a term that describes the quality of the out of focus areas in an image. What is good bokeh and what is bad bokeh? Umm... if you like the look of the out of focus areas it's good, if you don't, it's bad. That being said, characteristics of good bokeh include circular highlights with no "edge" to ...


2

I think you are seeing strong chromatic aberrations. Those come from different colors of light getting refracted slightly differently, so the focus points for the different colors are in different positions. The result is typically that parts of the shot off-center (and not necessarily out of focus) have purple and/or green halos. Green halos would not pop ...



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