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-...


15

The lens corrections aren't part of the firmware itself (i.e. a particular firmware doesn't mean you have a particular lens correction). They are profiles that can be stored in the camera, and you need to register them with the camera if they aren't in the default set. Canon DSLRs that support lens corrections (Peripheral Illumination and/or Chromatic ...


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 ...


11

Are you working with RAW or JPEG? RAW will not use the in-camera correction but JPEG will.


9

For lensfun <= 0.2.8, you may download http://wilson.bronger.org/db/version_0.tar.bz2, and extract its contents over your old database, which usually resides in /usr/share/lensfun (clean this directory first). For lensfun > 0.3.0, a simple "lensfun-update-data" on the command line, possibly with a "sudo", is enough. Both methods install the current (...


9

These features affect only the JPEG generated in-camera. For RAW processing, you can achieve the same results in Canon's DPP. Or use LR.


8

More image information? Yes. Better image quality? No. The parts being truncated don't scale well because of the rectangular pattern of your sensor's pixel wells versus the curved shape of the correction. So a lot of artifacts can show up in those areas. Like many products intended for mainstream consumption (as opposed to niche products used by experts in ...


8

RawTherapee, darktable, and other programs use lensfun for lens correction. If your lens appears to be absent from the database... Check the Lensfun coverage database to make sure it really hasn't been added yet. If it's already there, you may need to update your local copy (sudo lensfun-update-data). If your lens is not supported, you can read about how to ...


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

The answer is probably more profane than you think: Instead of developing a real sophisticated algorithm to get the best resolution out of the source image, the software developers went the "safe" way: add enough crop that will always and under all circumstances deliver an image that is "properly cropped" (whatever that means). I'm saying this as a ...


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 ...


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

Even I had experienced similar problems while shooting night sky photos and later stacking them together although not as apparent of a moire pattern as you have. after a bit of troubleshooting, I found out that by disabling Lens Correction before stacking the photos and applying it after stacking eliminates the problem. A side note would be that I used ...


6

Many modern digital cameras are designed with the expectation that lens compromises will be... de-compromised... in RAW processing. That appears to be the case here. The preview image is based on the JPEG rendering, which includes this processing. The RAW file, however, does not. The amount of apparent vignetting will not be dependent on the scene, but on ...


5

I'm guessing this has to do with two overlays that were very slightly misaligned from each other such that the small variations in each image due to the Bayer matrix become apparent. If so, this is a rare case where working in raw is actually hurting. Put another way, the raw data has some regular high frequency content due to the Bayer matrix. Normally ...


5

Perspective correction is possible in a film/enlarger/paper process, by setting up the paper in a non-parallel relationship to the film. The paper is typically held by an easel which holds it flat. Propping up the easel on one side brings the paper closer to the enlarger head on that side, which in turn increases both magnification and exposure on that side....


5

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 ...


5

I fixed this in the sources of Lensfun. It will be part of the next release. Until then, you can edit the file mil-panasonic.xml, probably in /usr/share/lensfun. Search for "12-32" in that file, and expand the lens model name to "Lumix G Vario 12-32mm F3.5-5.6 Asph. Mega OIS".


5

The lensfun website explains how to update lenses without root permissions (see how database files are found and loaded). What worked for me was: cd mkdir -p .local/share/lensfun cd .local/share/lensfun Then download and extract the updated lenses: wget http://wilson.bronger.org/db/version_0.tar.bz2 bunzip2 version_0.tar.bz2 tar xvf version_0.tar The ...


5

Since the cloth is white, and the other colour is black, you could simply desaturate( remove all saturation) at whole region of cloth. I've done the same multiple times


5

What you are describing are fundamental phenomena. The first phenomena illustrated with photograph of a ball and partially with a group photograph of people is resulting from incorrect viewing of the image. The optical behaviour of your objective is called rectilinear mapping and it is concerned as benchmark of optical behaviour: all lines are preserving ...


4

I solved the mystery! I shoot RAW, edit in Lightroom, and export to JPEG. In LR I normally check "Enable Profile Corrections" under Lens Corrections. When I unchecked this box, the photo exported without the moire. Not sure what's going on under the hood, but lesson learned.


4

The EOS Lens registration data is intended to be used by either: The camera when processing the raw data from the sensor to produce a jpeg image (or to produce a jpeg preview image when the file is being saved as raw data). At a minimum the camera uses the information to do Peripheral Illumination Correction. Some but not all Canon EOS cameras can also ...


3

Light fall-off depends on a particular lens at a certain aperture and for some focal-length. There are a number of cameras which can do this but they must be able to recognize the lens. This is a profile based approach and can usually be enabled some cameras with electronic lens mounts. A few other cameras allow to apply an amount of compensation, probably ...


3

It is only a very slight over-simplification to describe lateral chromatic aberration as the situation in which different colours produce pictures of slightly different sizes. Seen in that light, it's merely a matter of adjusting (slightly) the image size in one or more channels so that everything comes back into registration. In this article on The Online ...


3

Solution found. See below. Here are the steps I took to fix the issues described. uninstalled darktable and lensfun packages via synaptic. fresh install of darktable (which also installs the dependency of lensfun 0.2.8) unpacked lensfun 0.3.0 tar into my home directory, to folder lensfun-0.3.0 $ cd lensfun-0.3.0 $ gvim data/db/slr-nikon.xml copy and insert ...


3

In Lightroom there are various settings that come under the 'Lens correction' umbrella. The 'Enable Profile Corrections' flag will correct the image based on the type of lens it was taken with, so if you copy it from an image taken with a 10mm lens onto an image taken with a 20mm lens, it will correct the latter for distortions caused by the 20mm lens. If ...


3

On Windows, they can be found at: X:\Program Files\Adobe\Adobe Lightroom\Resources\LensProfiles\ On Mac, they should be here: Applications/Adobe Photoshop Lightroom X/Right-click Show Package Contents/Resources/Lens Profiles Source: Julieanne Kost: Where does Lightroom Install Camera and Lens Profiles?


3

You might be confusing "distortion" with "perspective". Remember, 50mm lens stays 50mm lens on D7200, just the field of view changes. When shooting too close (I think about ~0.5-1m) you might see that 50mm starts acting "wide". That means, that nose get bigger, ears get farther away from the nose and other perks of wide-angle lenses. Rule of thumb for ...


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