weird lens flare. need help

[natalka]

Can someone identify what this flare is? I have had this lens for several months...the body is over a year old. At last week's wedding, images randomly started having these green lights. They appear in both flash and non-flash pics.

http://www.borrowedbluephoto.com/images/weirdflare.jpg



Both body and flash just back from CPS two weeks ago.


Natalka[/img]

[robertwgross]

A few questions:

(1) Are the green dots in the same place on each frame? That would point toward a sensor problem.

(2) If the green dots are in different places frame-to-frame, then are they identical in size and shape? From the small image you posted, they seem to be, but some serious magnification might show something better.

(3) If it was plain lens flare, then the position would change radically as the lens direction was changed slightly (with respect to the scene lights).

---Bob Gross---

[natalka]

Okay, after looking at fifty more images, I can now see that the green flares are relections of the sconces or other pointed light sources, but why? I've shot 30 weddings with this particular camera/lens combination, why did the lens, or camera, start doing this now?

Natalka

[robertwgross]

So, I guess you are saying that the green dots move around from one frame to another based on the direction of the lens with respect to the scene lights. Are they the same size and shape from one frame to another?

With flare, the spacing of one dot to another will vary based on the direction of the lens.

A few ideas:

(1) Are you using any filters at all? Consider removing everything.

(2) Have you cleaned your lens front element with anything? If so, then consider cleaning it with something better. If a residue of human sweat got on the glass, that would explain a few things.

---Bob Gross---

[natalka]

It's not residue or dust, because the size and location change depending on the lights in the room.

I'm currently testing the lens/camera with and without my Nikon UV filter, and I haven't been able to duplicate the problem without the filter. Looks like that's the culprit.

It's weird, because I've been using this lens (24-70L) on this camera (10D) with the same UV filter for many weddings with no issues.

Natalka

[robertwgross]

It's not residue or dust, because the size and location change depending on the lights in the room.


That tends to make it flare.


I'm currently testing the lens/camera with and without my Nikon UV filter, and I haven't been able to duplicate the problem without the filter. Looks like that's the culprit.


We don't like to speak ill of the dead here.


It's weird, because I've been using this lens (24-70L) on this camera (10D) with the same UV filter for many weddings with no issues.


Maybe you used the same UV filter, but maybe you didn't shoot toward the lights the same way on earlier events.

---Bob Gross---

[natalka]

http://www.borrowedbluephoto.com/images/weirdflare2.jpg

Another example.

[robertwgross]

Wow. The two yellow ones are pretty serious.

I would take a close examination of the UV filter. See if it is "straight" in its mounting ring. If it were crooked to the axis of the lens, then that would explain a lot.

We could assume that a brand name like Nikon would at least make sure that the filter glass is optically flat. But if it got crooked in its ring, then that ruins it.

---Bob Gross---

[natalka]

Shot today at a very similar location with the same lighting conditions.
Took off the UV filter. I was unable to produce the same flare, so it looks like it's the filter and I'll use my lens hood instead of the filter in the future.

Natalka

[robertwgross]

Take the used UV filter and sell it on eBay as a special effects filter.

Don't try to sell it here. We've got your number.

---Bob Gross---

[natalka]

Don't try to sell it here. We've got your number.



lol



We shot the entire wedding yesterday without filters on our lenses, which made me very anxious, and with lens hoods instead. Similar lighting situation. Not a single reflection.

Can anyone venture a guess as to why those lens flares occurred for that one wedding, but not before? Same equipment used for many months, similar lighting situations encountered...


Natalka

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[robertwgross]

Can anyone venture a guess as to why those lens flares occurred for that one wedding, but not before?

As I stated before... look to see if the glass of the filter is still straight on the axis of the lens. Maybe you can see it, and maybe you can't. For example, if the filter's metal ring got warped, that would account for it. I saw a filter one time that had been disassembled and then reassembled incorrectly, and it had major problems afterward.

I would still make sure that the front element of my main lens was perfectly clean. That would account for a few things.

---Bob Gross---