Chromatic aberrations

Chromatic aberration in human language - These are color distortions that add various kinds of parasitic distortions to the original image.

Chromatic aberrations

Chromatic aberrations

If you’re an amateur, and somewhere you’ve heard that some lens gives you strong HA (chromatic aberrations, and that’s the way they are often called names for reduction), and then they looked at the photo for a long time and didn’t see anything - don’t be upset. Nowadays, the struggle over HA is in full swing. Now, in high-quality optics, it is very good at combating HA and therefore it is really difficult to notice them.

There are axial, spherical, transverse and other types, but they all come down to the distortion of the picture.

Summary the essence of chromatic aberration It resembles dispersion, in other words, when a white ray is decomposed into its spectrum - this is due to the fact that rays with different wavelengths (different colors) are refracted at different angles, passing through the objective lens. Suffice it to recall a physics lesson with the refraction of rays in a prism, and a lens is two prisms connected by bases. It turns out a flaky picture. Often, CAs add different color spots and stripes, this is especially pronounced in the transition of contrasting objects, often an example with trees is given.

Chromatic aberrations

Chromatic aberrations

Below is a snapshot full of aberrations.

An example of aberration. Red halos of a spider web.

An example of aberration. Red halos of a spider web.

 

Of course, there are a number of lenses (namely, lenses give HA), which nevertheless suffer greatly this affliction. But as they say: optimists invent a plane, pessimists invent a parachute, so you have to fight with HA in order to get high-quality images.

Chromatic aberrations

Chromatic aberration. Friging

Very often, HA is pronounced in the blur zone. Among the people, aberrations, usually in the blur zone, are called frying ('Purple fringing'). Transitions in the area in front of the field of sharpness are colored in purple (magenta), and behind the area of ​​sharpness in green. This is clearly seen in the example above. Many lenses have aberrations in the blur zone.

Spherical aberration

Spherical aberration

Spherical aberration is the blurring of boundaries between contrasting elements in the area of ​​sharpness in the photo. In the example above, the model's white shirt blends into the dark background, erasing the border. Monocles suffer from spherical aberrations. More details in the section monocle.

Parasitic glare

Parasitic glare

Sometimes purple and red halos in the photo are confused with CA. Halos are simply parasitic glare from a bright source in the frame. An example of such highlights is shown above.

How to be? How to treat this lens?
In modern lenses, they try to use fine elements. Nikon refers to them as ED (Extra-Low Dispersion - Super Small Dispersion). These elements give less refraction for rays with different wavelengths (for rays of different colors).

Also started to use now aspherical lenses, which allow you to get the final picture with less HA.
Modern advanced cameras have automatic control of aberrations - I don’t know how modern cameras do this (most likely using special algorithms), but they remove the aberrations with a bang.

I also recommend just remembering that aberrations appear with strongly contrasting elements in the frame (sun and sky, trees and sky, dark and light areas), when photographing a really strongly contrasting element, just remember that the photo will need to be finalized if HA appears.
Most XA appears on the open aperture when used on wide-angle and fast lenses, because HA visible on almost all cheap and mid-range lenses with a full aperture (under certain conditions).

Telephoto lenses have the most HA at the long end (maximum allowable focal length).
It is very easy (but not entirely correct) to get rid of HA - this is to take a photo in black and white.

If you need to completely get rid of CA during direct photography, then mirror lenses, in which they are completely absent, will help with this, an example of such a lens is MS MTO-11 1000mm F10.0.

Thank you for your attention, Arkady Shapoval

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Comments: 39, on the topic: Chromatic aberration

  • MELHAUZ

    It will be correct if we say: HA - is it color and other parasitic distortions in the frame?

    • Arkady Shapoval

      no, HA are chromatic (edging in the sharpness zone), while others are of a different type.

      • Rodion

        Please tell me, will filters help get rid of them?

  • MELHAUZ

    Clear.

  • Inna

    What is the cost of aspherical lenses?

    • Arkady Shapoval

      Pretty expensive compared to the usual ones.

  • VALENTINE

    My test: https://picasaweb.google.com/115262918420027354916/K5NJU37A. Lenses - Kaleinar-5N and Jupiter-37A. At infinity, Jupiter-37A is noticeably sharper because it has better chromatic aberration. The tone of the image in Kaleinar is colder than in Jupiter.

    • anonym

      I have Jupiter 37A. I practically didn’t notice HA at him. I shoot on D90

  • Vadim

    In many sources that caught my eye, fringing is not only attributed to chromatic aberration, but is considered their main visual manifestation:
    “The archetypal manifestation of chromatic aberrations is color fringing”
    (http://toothwalker.org/optics/chromatic.html)

    “Chromatic Aberration, also known as“ color fringing ”or“ purple fringing ””
    Read more: http://photographylife.com/what-is-chromatic-aberration#ixzz2NpdIt8la

    “Chromatic aberration manifests itself as“ fringes ”of color”
    (http://en.wikipedia.org/wiki/Chromatic_aberration)

    “The inability of a lens to bring all of the colors into a common focus results in a slightly different image size and focal point for each predominant wavelength group. This leads to colored fringes surrounding the image ”
    (http://www.microscopyu.com/tutorials/java/aberrations/chromatic/index.html)

    Just distinguish between axial (axial) and transverse (transverse) HA, corresponding to your examples.

  • Dmitriy

    Arkady, the previous comment is correct. Check out the links.

    There is chromatism of increase (transverse CA) and chromatism of position (longitudinal CA). “Purple fringing” is a slang term for purple fringes in general. The article should be slightly corrected and reissued.
    By the way, chromatic aberrations are specifically related to color (chroma = color). “.. or other distortions ..” - other distortions are simply called aberrations of such and such order.
    With all due respect to you! I also have enough materials for revision. I came across this article by accident because You were one of the first in your search and it was nice to visit Radozhiva.

  • Dmitriy

    Forgot to add.
    “..In our time, the fight over HA is almost over ..” - oh, if only .. :)

    • Arkady Shapoval

      Fixed

  • Dmitriy

    Now it’s good.

  • Anna

    Arkady, good afternoon. Please see this aberration?
    http://radikall.com/eeN
    Macro photo circles? Helios lens + macro rings. On some pictures this is not.

  • AnDeren

    Good day to all! Question to Arkady.
    I have a D3200 + 50mm f / 1.8G. I shoot (f / 1.8-4.0), for example, a gray box with a barcode on it. Here are some very strong pink and green HAs on the barcode line. I tried to photograph with the same lens on the D7000 - there is simply no XA. What could be the problem?

    • Arkady Shapoval

      Different control function HA.

  • Alexey

    ... decomposes into a spectrum from violet to blue ...
    Rather to red?

  • Dmitriy

    I heard that it’s even becoming fashionable)))))

  • Andrew

    Arkady, good. We know that aspherical lenses come to the rescue to combat HA.
    What elements are needed to eliminate CA?

  • anonym

    Gentlemen photographers! Lovers and pros! I have a very unusual Asanuma auto-zoom 1: 4.5 f = 90-230 tele lens. To be honest, I took only 2m. criteria: price and “try the first telephoto lens”. I took a couple of first shots, and was unpleasantly surprised, it immediately became clear that something was wrong with the lens. I came across your discussion, and I finally realized what the problem is, those very mean, chromatic aberrations, and very noticeable. The question is, has anyone ever used this rarity? And if you use it, tell me if this is his feature, the lens in the sense, or was I so lucky?

    PS
    If someone tells me about this lens, at least something in general, the story is there, features, or better, will make some kind of brief review, I will be very grateful! Thank you in advance!
    The photo taken from this lens, I send for my passive help. Made on a Nikon D5200 camera

    • BB

      You’d better put a crop of the frame 100%, with these very aberrations.

    • Lynx

      Well, you have a VERY contrasting object on the stage gave HA.
      not to say that it is scary - in lightroom this is removed in a couple of clicks.

  • anonym

    100% crop frame. Here it is. Although, how does this relate to my question, I don’t really understand something .. :)

  • Sergei

    But is it not frigging in the zone of blur?

  • anonym

    And what is frigging?

  • Sergei

    4th top picture in the article

  • Sergei

    Arkady, do you use the automatic HA removal function on your cameras? or, then, during post processing?

    • BB

      If you plan to postprocess, then shooting is carried out in RAW. In Lightroom XA, they are corrected in two clicks.

      • Sergei

        I'm lazy! take off rav + zhpeg :-)

  • anonym

    Good afternoon, tell me how to remove chromatic aberration using Photoshop?

    • Igor

      in ACR

  • AS

    But this https://yadi.sk/i/jKJTiSVf3JdkYk
    https://yadi.sk/i/ulJMVora3Jdm6D from the same category or not?

    • Michael

      No, it's more like a moire. Very cruel, really. I have never received on such large items.

  • Oleg

    And will HA depend on the pixel density of the matrix? From the Bayer / skyer pixel arrangement? If we compare, say, the Sony A6000 and Fujifilm X-E2 matrices with the same lens. Of course, completely HA will not disappear, but their intensity can change?

  • Edward

    A great article, but I think that the topic of spherical aberrations is not fully disclosed.

    Spherical aberration is not a distortion of colors, namely, the so-called soft effect, those are not sharp distortions at the edges

    And they struggle with them, including those mentioned, aspherical elements

    Spherical aberrations will be exactly the same visible for b / w images, they are not connected in any way with color, but are connected with different rays passing in the center and along the edges of the lenses

    Aperture is an effective way to deal with them, since this leads to less light coming from the edges of the lenses

    • Vitaly N

      Especially when you consider that the article is not about them.

      • Edward

        they are mentioned:
        1) ”Spherical aberration is the blurring of boundaries between contrasting elements in the sharpness area in the photo. In the example above, the model's white shirt blends into the dark background, erasing the border. ”
        2) "Also now we started to use aspherical lenses, which allow you to get the final image with less CA."

        1) true, but for non-contrast elements everything will be the same, just less noticeable
        2) aspherical lenses have no direct relation to CA - they fight precisely with spherical aberrations. Hence their name.

    • anonym

      Here they brought a solution to spherical aberrations: https://petapixel.com/2019/07/05/goodbye-aberration-physicist-solves-2000-year-old-optical-problem/
      Translation: https://3dnews.ru/990355

      The formula delivers, however, the lens according to this formula, too.

      We are waiting for the lenses.

  • anonym

    My situation is as follows:
    Canon EF50mm 1,8 STM lens on the 1200D camera XA is not available and more than enough on the 50D.

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English-version of this article https://radojuva.com/en/2011/04/chromatic-aberration/