Canon 24-105mm F4 L issues!!!

[huy_nguyen12]

<p>Hello everyone,<br /> Today, when i take a picture with 24-105mm F4 L lens and i saw big issue with my lens. A part close to optical lens look like react with something. Please help me explain the reason of issue and how to fix it.<br /> Thanks,<br /> Huy Nguyen<br /><img src="https://drive.google.com/file/d/0B7FBhfemmGgAOTlHeGlZNHRHYWs/view?usp=sharing" alt="" /><br />Lens photo: https://drive.google.com/file/d/0B7FBhfemmGgAOTlHeGlZNHRHYWs/view?usp=sharing</p>

[JosvanEekelen]

<p>Never seen this before. Can the front element have acted as a magnifying glass and coused overheating of the lens innards?<br>

I'd contact Canon for repair and a possible cause.</p>

[JDMvW]

<p>Had you exposed the lens to heat, laser beams, death rays, lately? Another who has never seen anything like this in a lens before. From the picture, it looks like the plastic (?) is melted and bubbled up:</p>

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

[huy_nguyen12]

<p>@<a href="/photodb/user?user_id=1841065">JDM von Weinberg</a>: I'd just take some silhouette picture in the morning sunshine before i see it</p>

[AzDavid]

<p>Looks like something dripped onto the lens at a time when it did not have that protective UV Haze filter (or whatever it is). Maybe glue of some sort? I'd have somebody qualified take a close look at it. That's not a cheap lens!</p>

[Charles_Webster]

<p>Tree sap?</p>

[JosvanEekelen]

<p>I had to double check it but this is behind the frontlens, behind the glass. Curious as to what happened.</p>

[Charles_Webster]

<p>Jos, I believe there is a filter on the front of the lens and that the unknown matter is on the front element surround.<br>

Huy Nguyen, was the filter in place when this happened?</p>

<p> </p>

[huy_nguyen12]

<p>@David Hoye, @Charles Webster:I used UV Haze filter of all time when I buy this lens. I think lubricant oil or something similar from motor,coupling,... inside the lens make this happen !?</p>

[AzDavid]

<p>Looking closer at the image (via the link provided) it seems as though the mystery substance is inside the lens, itself. You can see how it seems to follow the circular ridges that ring the central glass. If so, I think the substance is from the inside of the lens ... perhaps lubricant that leaked due to high temperatures? Was your camera/lens exposed to excess heat? Say, inside a hot car on a sunny day? I still think your best option is to have it examined by an expert!</p>

[JDMvW]

<p>BTW this is beneath the outer part of the lens, beneath the outer lens element -- not exposed to the elements.<br>

The lens in the picture is probably set to 24mm.<br>

As you can see below, the area with the goo/bubbled plastic/whatever is beneath the distal lens element</p><div></div>

[Robin Smith]

Doesn't look as though it will affect the lens' performance in any way, so why worry? It might affect resale value, but even

then I'm not sure it would.

[JDMvW]

<p>I would also feel that it does no harm, except cosmetic, where it is; but if it were mine (heck even with it being yours) I would like to know what caused it.</p>

[Mark Keefer]

<p>It does seem to be beneath the outer lens element, if this is liquid I have no idea how it would get there, it appears to be grease. I don't know if Canon greases their lenses or has a lubricant packed inside? If this is the case I would contact Canon if they have an idea what is happening? Manufacturer defect?</p>

<p>Another thought is it is melted plastic. Were you shooting into a magnifying glass or magnifying mirror pointed at the sun?</p>

<p>I have seen laser pointers modified with old DVD burner lasers that could easily melt black plastic. If someone pointed this at your lens while you were shooting you are lucky it did not go in the aperture opening or you might have retina damage and or sensor damage. A modified laser pointer would probably have to be close, like under 20 feet. You could find an example of this on YouTube. This is just speculation.</p>

<p>What ever happened seems strange. If you get any answers, please update us.</p>

[huy_nguyen12]

<p>Thanks for all help, i'll update answers if i know more about this! </p>

[matthias_meixner2]

<p>That might have been caused by concentrated sunlight. Did you mount a lens-cap when not in use? If not, this might have happened when the camery was laying about and not during shooting.</p>