# 100-400mm L ....          sometimes you just get graced!



## Soocom1 (Jun 29, 2020)

So selling back of sick leave time came. 

I sold back all hours over 460 hrs of sick time back to the county and waited. 

During my wait, I went looking for any Canon L lens that would replace my 35-350 that died last year. 
Well while hunting around I came across an Adorama listing for a canon 100-400mm L that was listed as "Fair". 

The price..... 
$375.00   (yes USD!) 

why? 

Well as they put it, it had two specific problems: 
1: The lock ring wasn't working anymore and 
2: "Severe Fungus" on the front element. 

OK, so I bought it. Yes it was a risk, but hey.. sometimes you just have to try. 

Today it came in... 






lets see... 
Bag: Check.
lens: Check.
Caps: Check.
Shade: Check. 
All here, all good. 
So what does it look like? 






Front element..... Bad! ouch!  

And yes, the lock ring didn't work. 

So some exploratory surgery and the element came out nice and easy...





Yes, thats fungus! 


I put some fresh tape on the lock ring for gripping and put it back into place..


Now the part everyone is going to hate... 





I wiped the element with a glass cleaning towel from the dollar store. 





Look ma.... No fungi..................................................................................






Reassembled and and a quick check of functions.. and voila... 






I'm back in business...


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## Mike Drone (Jun 29, 2020)

Nice find!


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## Derrel (Jun 30, 2020)

Nice!


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## mjcmt (Jun 30, 2020)

Awesome. I love those kind of finds and the satisfaction of repairing it. Congratulations.
Question though... what is the locking ring and how does tape fix it?
Also, how does front element come off?

BTW, I wonder haw fungus got in the inside. Is this lens not water resistant?


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## zombiesniper (Jun 30, 2020)

Great find and fix. For that price how could you not give it a go.



mjcmt said:


> BTW, I wonder haw fungus got in the inside. Is this lens not water resistant?



This era of 100-400mm from Canon has a push pull zoom on it. It is nicknamed the vacume cleaner for a reason. Unlike a twist zoom (most of the higher end Canons do not extend) this one you push or pull the zoom section which extends or retracts the lens. Because of this it is not really weather sealed all that well. Some worn in models you can actually hear the air rushing in and out as you use it.


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## PJM (Jun 30, 2020)

Way to go!


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## Soocom1 (Jun 30, 2020)

The lock ring is what holds the slider in place when walking around with a camera hanging from your neck. 

The issue is that the slider is very heavy and it can bang either forward or backward. So they put a friction ring in place using a threaded turn ring that when turning pushes a split ring to close around the barrel of the main body. 

This friction ring has a "rubber" strip that is similar to friction tape but really thin!  When you twist the lock ring the split ring is twisted upward and closes. The friction band grabs the barrel and the whole mechanism locks in place.


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## Soocom1 (Jun 30, 2020)

The front element is held in place with a set of screws. You dont want to simply remove them however, the front element is calibrated to a specific distance so as your removing retaining rings you have to mark the position of the element and the screws with white out or similar. 
Then once the screws are out, the element simply pops out.


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## Jeff G (Jun 30, 2020)

Nice score and repair!


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## K9Kirk (Jun 30, 2020)

I am prepared to give you $376 for it right now. 

Nice find, I hope it serves you well. Can't wait to see some pics from it.


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## Soocom1 (Jun 30, 2020)

K9Kirk said:


> I am prepared to give you $376 for it right now.
> 
> Nice find, I hope it serves you well. Can't wait to see some pics from it.



Add a zero. 


Here ya go, from last night with a 1/12000 ISO hand held with the IS on.


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## Soocom1 (Jun 30, 2020)

From today on the tripod...


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## Mike Drone (Jun 30, 2020)

Soocom1 said:


> K9Kirk said:
> 
> 
> > I am prepared to give you $376 for it right now.
> ...



$0376  Done  =]

Nice photos!


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## photoflyer (Jul 2, 2020)

Low risk, high reward.  Maybe Canon should outsource some refurb work to you.


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## Soocom1 (Jul 4, 2020)

A dove in the morning. 







now I understand why the birders love this lens so much. 


Full 400mm


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## Space Face (Jul 4, 2020)

Cracking lens and always good to get a bargain.


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