What causes these halos/artifacts?

[Glaucoides]

I was shooting some distant gulls yesterday, and noticed some artifacts in the photos. Here are a couple of examples, both very heavily cropped. In the first image, the gull swimming on the water has a white angel-halo around its head, and an orange artifact on the lower part of its beak (seen through a telescope, the beak was all yellow; this species of gull never has orange on the beak). This was the focal bird at the center of the picture; most of the 10-15 other gulls in the picture didn't show any sign of these halos/artifacts.

In the second image, the flying gull has a small orange-brown artifact just below and to the right of the big white patch on its right wingtip (in real life, the wingtip is black and white with no orange-brown coloration whatsoever). I had several other similarly odd marks or blobs of color show up in other distant photos too.

What causes these types of photo artifacts?

Thanks!

 

[Derrel]

Inexpensive zoom lenses often have rather noticeable chromatic aberration are their longer focal lengths. Around each Bird's outline is a very small week secondary outline which can at times be a so-called ghost image which candy do to camera or subject movement such as when following a fast-moving object and Swinging the camera a little bit too fast or too slowly and not tracking the subject perfectly. The foggy appearance around the top bird is something that can be caused by a number of factors. One factor could be a secondary image caused by an inexpensive protective filter in front of the lens. A second factor could be caused from seaspray, which creates a foggy effect. Third Factor could be that light colored subjects seen against darker Fields as they are called often show haloing or ghost images very clearly as white light scatters someone into the shadowed areas nearby and thus causes this glowing effect. As far as the color abnormality on the yellow beak, every Digital Image must be the de-mosaiced, and since the beach is a very small portion of the entire image field the data the computer uses to decode the image can be prone to color errors especially in such a small physical portion of the entire sensor.

When asking for help diagnosing problems it is usually best to State the equipment used. Looking at these images with no exit data my guess is long and expensive telephoto zoom lens. Possibly a filter over the lens. Most likely some sea spray on the front of the lens in a thin film, a coat of microdroplets, causing the glowing effect in the top photo. It's possible other Optical problems could also be in existence here.

 

[john.margetts]

Heavily cropped? How heavily? Are the artifacts visible if the picture is not cropped at all? The more you magnify any picture, the worse the quality becomes.

 

[Glaucoides]

Inexpensive zoom lenses often have rather noticeable chromatic aberration are their longer focal lengths. Around each Bird's outline is a very small week secondary outline which can at times be a so-called ghost image which candy do to camera or subject movement such as when following a fast-moving object and Swinging the camera a little bit too fast or too slowly and not tracking the subject perfectly. The foggy appearance around the top bird is something that can be caused by a number of factors. One factor could be a secondary image caused by an inexpensive protective filter in front of the lens. A second factor could be caused from seaspray, which creates a foggy effect. Third Factor could be that light colored subjects seen against darker Fields as they are called often show haloing or ghost images very clearly as white light scatters someone into the shadowed areas nearby and thus causes this glowing effect. As far as the color abnormality on the yellow beak, every Digital Image must be the de-mosaiced, and since the beach is a very small portion of the entire image field the data the computer uses to decode the image can be prone to color errors especially in such a small physical portion of the entire sensor.

When asking for help diagnosing problems it is usually best to State the equipment used. Looking at these images with no exit data my guess is long and expensive telephoto zoom lens. Possibly a filter over the lens. Most likely some sea spray on the front of the lens in a thin film, a coat of microdroplets, causing the glowing effect in the top photo. It's possible other Optical problems could also be in existence here.

These were taken with a Canon PowerShot SX60-HS, with the built-in lens (no additional detachable lens). There was no sea spray as this was on a large pond.

The orange spot on the beak appears in the image when I'm viewing it on the camera's playback screen too, not just on the computer. Is that still likely to be an image decoding error, or is it something else?

 

[jcdeboever]

I have that camera, when you get into digital zoom or even just prior, without a tri-pod, this is what you can encounter. You went beyond the stabilzation as well. F/8 is the smallest aperture it will go to as well. Images at long focal lengths (digital zoom) are pretty decent when on a tripod. Of course, birds in flight are usually shot hand held and difficult to get a clean shot. Additionally, it is a small sensor that is crammed with 16 mega pixels. Good camera when you understand its limitations.

Sent from my XT1254 using ThePhotoForum.com mobile app

 

[Derrel]

Ahhhh. Canon PowerShot SX60-HS....

Lens quality issue,most likely. Do check front element for any smears, due to airborne cooking oils, air pollutants, ciagrette or woodsmoke, etc.. Sometimes an almost invisible, light,light film can cause that type of halation or "fogging" in conditions like the above, and an immaculately clean lens can help alleviate that. I assume now, know that this was from a superzoom type camera, that we're dealing with long-lens issues, which are pretty common on extreme crops like this.

 

[Glaucoides]

Ahhhh. Canon PowerShot SX60-HS....

Lens quality issue,most likely. Do check front element for any smears, due to airborne cooking oils, air pollutants, ciagrette or woodsmoke, etc.. Sometimes an almost invisible, light,light film can cause that type of halation or "fogging" in conditions like the above, and an immaculately clean lens can help alleviate that. I assume now, know that this was from a superzoom type camera, that we're dealing with long-lens issues, which are pretty common on extreme crops like this.

OK... But does that also explain the orange artifact on the bird's beak? Like I said, this artifact is apparent when I view the image on the camera as well as on the computer, so it's not the result of a computer "messing with" the images after downloading them.

 

[Derrel]

Every single digital color image is made onl;y AFTER the camera de-mosaics or "decodes" the original data. On a very teensy-tiny part of an image, there might not be enough original data to create a 100% accurate decoding of the digital data. if there are not "that many pixels", the demosaicing software will have to, literally, approximate, or guess, what colors to make the things that were in front of the lens.

The issue is not on the computer, but results from the in the field decisions the camera's software and hardware made when it took the sensor dats, and then turned that into a photo, using pixels. This is usually worst on small, small details. you're right when you state, "it's not the result of a computer "messing with" the images after downloading them." It happened earlier, at the pond.

Notice that the so-called Big Things look pretty much as expected; but that small bit of yellow was determined to be "orange", based on the demosaicing algorithm, and the small amount of data it had to work with.

 

[Glaucoides]

Ahhhh. Canon PowerShot SX60-HS....

Lens quality issue,most likely. Do check front element for any smears, due to airborne cooking oils, air pollutants, ciagrette or woodsmoke, etc.. Sometimes an almost invisible, light,light film can cause that type of halation or "fogging" in conditions like the above, and an immaculately clean lens can help alleviate that. I assume now, know that this was from a superzoom type camera, that we're dealing with long-lens issues, which are pretty common on extreme crops like this.

Thanks for all the info on this!

I checked my front lens and found that it was dusty, with particles of what appeared to be common house dust. Is that a likely culprit for the halos?

 

[Derrel]

Ahhhh. Canon PowerShot SX60-HS....

Lens quality issue,most likely. Do check front element for any smears, due to airborne cooking oils, air pollutants, ciagrette or woodsmoke, etc.. Sometimes an almost invisible, light,light film can cause that type of halation or "fogging" in conditions like the above, and an immaculately clean lens can help alleviate that. I assume now, know that this was from a superzoom type camera, that we're dealing with long-lens issues, which are pretty common on extreme crops like this.

Thanks for all the info on this!

I checked my front lens and found that it was dusty, with particles of what appeared to be common house dust. Is that a likely culprit for the halos?

Well...it could be, because what keeps dust on a lens is often verrrrrrry fine,fine coastings of air pollutants, or the off-gasses from foam, from wood drawers, and from synthetic fabrics/carpets/upholstery; also, fine, fine airborne cooking oil, or cigarette smoke, or incense...all these things can create a very thin film which DOES cause haloing, and which does hurt shots made shooting toward bright light sources.

 

[Glaucoides]

Ahhhh. Canon PowerShot SX60-HS....

Lens quality issue,most likely. Do check front element for any smears, due to airborne cooking oils, air pollutants, ciagrette or woodsmoke, etc.. Sometimes an almost invisible, light,light film can cause that type of halation or "fogging" in conditions like the above, and an immaculately clean lens can help alleviate that. I assume now, know that this was from a superzoom type camera, that we're dealing with long-lens issues, which are pretty common on extreme crops like this.

Thanks for all the info on this!

I checked my front lens and found that it was dusty, with particles of what appeared to be common house dust. Is that a likely culprit for the halos?

Well...it could be, because what keeps dust on a lens is often verrrrrrry fine,fine coastings of air pollutants, or the off-gasses from foam, from wood drawers, and from synthetic fabrics/carpets/upholstery; also, fine, fine airborne cooking oil, or cigarette smoke, or incense...all these things can create a very thin film which DOES cause haloing, and which does hurt shots made shooting toward bright light sources.

I looked closely at the lens under bright indoor light and didn't see any film. Just dust particles clinging to the glass. Can these films be fine enough to be invisible even under bright light?

(I'm starting to wonder if this might be something more ominous, like digital corruption or water spots from dried condensation somewhere deep inside the lens...)

 

[Derrel]

My guess is the lens itself has some optical flaws that are visible under close,close scrutiny, at high magnification. But it could be a slightly decentered internal lens element (there might be 10,12,13,15 of them, total). And yeah, there could be internal accumulation like from vaporized lubricants: the old camera-kept-in-174-degree-car-glovebox-for-a-week-in-August syndrome.

I just thought of something! it is ALSO possible, and I had forgotten this: at high shutter speeds, over about 1/500 second, if in-camera or in-lens stabilization is left turned ON, it can cause this type of a weird, ghosting over an image. OS,IS,and VR lenses can get caught in a so-called "stabilization loop" when shot at high shutter speeds: I have personally had a similar issue as yours, about 11 years ago.