Strange artifact question.

[mbkissel]

<p>I was culling a few photos from this past Friday and was about to delete this one when I noticed an unusual artifact that I have not seen before. I was shooting handheld with a 7D, 100-400L IS, no filter, lens hood in place. Sunny day, around noon. EXIF should be intact. I have not seen anything like it in photos taken before or after this shot. I did not notice it when I took the shot, although it may have been there and I just didn't see it. I'll post a crop for a close up of the artifact. This shot is a jpeg of the original raw image. I see the artifact in the raw image, so it's not related to conversion. It's just a curiosity question more than anything else. What could it be? </p><div></div>

[mbkissel]

<p>And here is the crop.</p><div></div>

[JDMvW]

<p>I think you may have captured a rare cryptozoömorph known as a rod (<a href="http://en.wikipedia.org/wiki/Rod_%28optics%29">link</a>).<br>

That is </p>

<blockquote>

<p>rods are mere tricks of light which result from how images ... of flying insects are recorded and played back. In particular, the fast passage before the camera of an insect flapping its wings has been shown to produce rodlike effects, due to motion blur</p>

</blockquote>

<p>Very tiny gnat <em>really</em> close to the front of the lens could do it, maybe even at 1/400.</p>

[scott_ferris]

<p>It looks like a drying mark to me.</p>

<p>Yes my tongue is very definitely in my cheek, but it does!</p>

[bobatkins]

<p>To be honest I can't see an artifact. What am I supposed to be seeing?</p>

[mbkissel]

<p>JDM, I like the alien thing. Unless someone comes up with a more plausible explanation, I'm going with that. </p>

<p>Scott, lately I've been having trouble hanging digital images on the drying line. ;-)</p>

<p>Bob, look carefully at the rod shaped (tubular shaped) ghost-like artifact right in the center of the crop. It's slanted down from right to left.</p>

[mbkissel]

<p>Right here, Bob.</p>

 

[mbkissel]

<p>Right here, Bob.</p>

[mbkissel]

<p>One more time...gateway keeps timing out.</p>

<p> </p><div></div>

[patrickwells]

<p>The odd thing is it is only on the one petal . Possibly starting behind the right hand petal but tapering off and ending prior to the edge of the petal. I would think that a bug ghosting would have ended in a bug or continuing past the edge of the petal .I am just thinking out loud. Could it have been a reflection of some sort?</p>

[JDMvW]

<p>Normally the "rod" effect is from interlacing on video, but the images never show a "bug" at the end or beginning because the whateveritis is moving at a constant rate relative to the sensor plane for the short time it is in the picture.<br /> What makes it blurred and makes the relative velocity seem high is that the object is small and very close to the lens. 1/400 is awful fast for this, I admit, so I wouldn't try to push it too far.<br /> What does look like the 'rod phenomenon' here is that the thing <em>seems</em> to pulse, which could be the tiny wings beating....</p>

<p> </p>

[alan_bryant1]

<p>It looks like it's in focus, which implies that it's very near the flower. The flower is somewhat enlarged - whatever it was moved maybe 3/4 of an inch? In 1/400 of a second? That's 300 inches/second -> 25 feet/second -> 1,500 feet/minute -> 90,000 feet/hour -> 17 miles/hour. Which strikes me as a plausible speed for a flying bug. I think that's what it is. Nice catch.</p>

[zml]

<p>Unless it shows up consistently on all shots in the same place, it is a part of the scene this way or another.<br>

As an aside, you must have a sh!tload of time to look for stuff like that on a single frame.</p>

[mbkissel]

<blockquote>

<p> "...time to look for stuff like that on a single frame."</p>

</blockquote>

<p>Actually no, Michael. But maybe I look at my photos more closely than you do yours?</p>

[Laura Weishaupt]

Mark,

 

That might be a spider web remnant. There might be only a couple of little strands and the light hit them just right.

[Robin Smith]

<p>Looks like a simple shaft of light to me. I don't think it is an artifact.</p>

[jim_service]

<p>I'm with Laura, I think it's an oof spider web strand.</p>

[JDMvW]

<p>Alan, thanks for the bug velocity calculation.</p>

<p>I love this club (as Calvin and Hobbes used to say). :)</p>

[Laura Weishaupt]

I have a photo taken this morning which shows the subject "lines". They are on a flower with a small spider inside. I'm happy to post it here for comparison, if that's ok. I didn't notice them till I looked at my shots on the computer. They are spider web strands.

[mbkissel]

<blockquote>

<p>I'm happy to post it here for comparison, if that's ok.</p>

 

</blockquote>

<p>Please do, Laura!</p>

[Laura Weishaupt]

I'm no good with arrows. Look behind/above the spider and also in front and below the "top" legs. I took 2 other shots and they don't show up due to different focus and lighting. I see this kind of thing frequently as I take a lot of close up photos in the woods, or as you did, in a place where a spider would want to get a meal. This flower is a beat up native Azalea about 1 3/4" wide.<div></div>

[Laura Weishaupt]

Here is a crop and another one shows up.<div></div>

[Laura Weishaupt]

Those look much better raw. It's not a particularly sharp shot either. Darn breeze. Here's another hot off the card, taken this evening. I decided to use a flash and see what happens. The single strand is longer in this shot. The light hit it just right for some of the strand to show. This is a crop.<div></div>

[mbkissel]

<p>Thanks for posting these shots, Laura. There is a great deal of similarity in your first shot. I did note a few spiders here and there amongst the flowers. I have never noticed anything like this in my photos before and it caught my eye. Thanks for your very plausible explanation.</p>

<p> </p>

[Laura Weishaupt]

Glad to be able to shed light on the subject.