topic Re: Fungus in Lens? in EF & RF Lenses

Fungus in Unused EF 100-400mm Lens?

Cajun — Thu, 09 Jan 2025 13:04:48 GMT

I recently was trying to sell a lens that is brand new. (Canon EF 100-400mm f/4.5-5.6L IS II USM)

I purchased it in February of last year (11 months ago) and never used it. I never even took it out of the bag it came in, plastic it came in, or box it came in. I just never got around to using it like I thought I would... sadly..

Not going to name any companies, but I went to sell it online after having little success with FB marketplace.

They offered me $550 because theres a spot of "fungus" dead center on the glass.

Has anyone ever heard of this? I understand if I were to have used the lens, brought it out in the elements, and put it through the wringer but none of my other lenses have ever had this issue.

I just cant bring myself to believe this, but maybe someone has heard of this and can shed some light on this.

Thanks!

Re: Fungus in Lens?

shadowsports — Wed, 08 Jan 2025 22:46:16 GMT

Greetings,

Sorry you are in this predicament.

Damage aside, when you decide to sell gear, the reseller is only going to give you pennies on the dollar. They are in it to make a profit, understandably so. I always sell my stuff privately. It takes longer but the ROI is usually better.

If your lens has fungus, you're at their mercy. You won't command a premium price, even if it doesn't affect photos. I've never had a lens purchased new have such a defect. Dust and moisture are the primary causes. Fungus spores are opportunistic. Where the lens was stored was probably a contributor. At this point you don't have recourse so you can get the lens repaired or part with it.

Re: Fungus in Lens?

March411 — Thu, 09 Jan 2025 01:32:41 GMT

@Cajun wrote:

I recently was trying to sell a lens that is brand new. (Canon EF 100-400mm f/4.5-5.6L IS II USM)

I purchased it in February of last year (11 months ago) and never used it.

If you purchased it new and it was from an authorized dealer it should still be covered under warranty. Did you purchase it from a Canon authorized dealer? Is it registered with Canon through their product registration portal on their website? Have you contacted Canon?

Save yourself some time and frustration and call them @ 800-385-2155 or 800-652-2666

Re: Fungus in Lens?

shadowsports — Thu, 09 Jan 2025 01:57:14 GMT

Greetings,

I do not believe fungus is covered under standard warranty. He could ask, but I believe the probability is low.

Re: Fungus in Lens?

March411 — Thu, 09 Jan 2025 02:08:17 GMT

I believe he will get the best recommendation from Canon over anyone that can give him feedback on the forums. It never hurts to try and in my opinion it is always a good path to go directly to the best source which would be Canon.

Re: Fungus in Lens?

Ron888 — Thu, 09 Jan 2025 05:37:42 GMT

Oh that's a shame.Definitely check on the warranty situation.
Unfortunately fungus is everywhere, all it needs is the right conditions to grow. Just to be on the safe side i need to ask : is the fungus on an outer lens surface? If so, lens wipes will fix it.But i'm guessing you would have done that already.
So if it's inside the lens, you should check with Canon's repair service.It may be easy to fix! Depending on the lens design,sometimes its super easy to remove front or rear elements for cleaning. Chances are it wont have left lasting damage.
In truth a small amount of fungus wont affect a lenses optical performance, but it does affect resale value.Unfortunately you'll be stuck with the low offers until it's fixed.

Ron ,Australia

Re: Fungus in Unused EF 100-400mm Lens?

ebiggs1 — Thu, 09 Jan 2025 15:19:03 GMT

"It may be easy to fix! "

Fungus doesn't have a repair possibility. It has only a replace option. Fungus lives on the lens coating so if present it has eaten, destroyed, the coating which is not repairable only replace. If the situation is as the OP describes is totally accurate, I can't imagine it even being fungus. That means it must be sent to Canon for evaluation. They will know. Call today 1 (800) 652-2666

Re: Fungus in Lens?

Cajun — Fri, 10 Jan 2025 04:19:02 GMT

Unfortunately, purchased through amazon. Will have to see. I never registered it because it just sat there but maybe I should be able to reach out to canon and see what they can do, not a bad idea.

Re: Fungus in Unused EF 100-400mm Lens?

Cajun — Fri, 10 Jan 2025 04:20:30 GMT

The whole thing is odd haha, its never touched air. I put it on a shelf in the box that it came in, and boom, it now has fungus a year later. Doesnt make sense but hopefully I can get some answers out of talking to canon. 😄

Re: Fungus in Lens?

March411 — Fri, 10 Jan 2025 04:21:36 GMT

You can also create an account on Canon and see if it will allow you to register the lens.

Re: Fungus in Unused EF 100-400mm Lens?

ebiggs1 — Fri, 10 Jan 2025 15:47:05 GMT

Well every story has details that are not known or let be known or perhaps even remembered. Call Canon 1 (800) 652-2666. You will need your receipt when you call.

Re: Fungus in Unused EF 100-400mm Lens?

Ron888 — Sun, 12 Jan 2025 01:02:07 GMT

When i said fungus spores are everywhere i wasnt kidding😄

Re: Fungus in Lens?

JFG — Sun, 12 Jan 2025 22:04:43 GMT

Amazon is an authorized dealer if it was sold by Amazon, not a third party.