# Workaround for Loose Lens Cap on 8-15mm Fisheye



## AudioGlenn (Dec 24, 2012)

I've heard about the loose-ness of the 8-15mm Fisheye lens cap and found a quick solution to the problem as I was opening my newly arrived lens today.

There's a scratch-resistant paper on the lens between the front element and the lens cap. This is how Canon packaged it so I'm assuming it's pretty safe for the protruding front lens element. If you keep that paper on before putting the lens cap back on and storing it, the lens cap stays on with much more grip and is not as easy to bump off.

I've seen posts regarding this before but couldn't find any specific to this topic. I remember reading about someone who actually thought to super glue the hood and lens cap together. Although not perfect, I think the paper in between is a slightly more elegant solution. Hope this helps someone else.


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## picturesbyme (Dec 24, 2012)

Had a similar prob on my Sigma 8-16.
2-3-4 small squares of black electrical tape always fix loose hood/cap problems.

What am I doing here.. dinner is about ready


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## Cinto (Dec 25, 2012)

I only use mine on a 5D2 so I just taped the two parts of the lens cap together.


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## wopbv4 (Dec 25, 2012)

Indeed, I used superglue.
for me it is important that the lens is protected in my camera bag.
In use, I do not use the lens cap/lenshood at all on my 1DX.

Initially I used your solution with scratch resistant paper, but on several of my hiking trips the lenscap came off in by backpack, so I glued the cap and the hood together


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## AudioGlenn (Dec 25, 2012)

wopbv4 said:


> Indeed, I used superglue.
> for me it is important that the lens is protected in my camera bag.
> In use, I do not use the lens cap/lenshood at all on my 1DX.
> 
> Initially I used your solution with scratch resistant paper, but on several of my hiking trips the lenscap came off in by backpack, so I glued the cap and the hood together



nothing wrong with your solution at all. I'm considering taping the two together anyway just for that extra bit of security.


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## Quasimodo (Dec 25, 2012)

Interesting thread. Just got mine four days ago.


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## RMC33 (Dec 30, 2012)

I keep mine in a pelican case. Had not had this issue yet but I can see how it would happen. Mine is not all that loose though.


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## iohansen (Jan 13, 2013)

The problem with the cap is that the it uses two latches on the cap to fix it to the hood (using inside ridges at the end of of the long hood petals). These latches does not have enough force to keep the cap in place, indeed it is possible to drop the cap merely by shaking the lens/hood/cap (if it's in the "wrong" position). So how to increase the force provided by the latches?

This is relatively easy, the cap latch mechanism is a single plastic construction that can be removed (this relates NOT to the hood with its single release button). This is done by pushing one of the latch buttons all the way in, towards the centre of the cap, and then gently pressing it down into the cap, it should release/pop out of the inside grooves. 
Repeat for the opposite latch. The entire latch ring can now be removed. It has the shape of a slightly flattened circle with the latches at opposite ends. At the inside of the push buttons one can see the latch ridges that interlocks with the hood.
To increase the holding force, the latch ridges should be made to be further apart. This can be done by placing an object inside the ring that increases the distance between the latches by approx 3-5mm (the ring will now look more circular).

Now for the scary part, use an adjustable heat gun with a narrow nozzle (10mm diameter) to reshape the plastic. The temperature of the air hitting the ring surface should not exceed 120 C, too hot and the plastic *will *melt (forcing you to buy a new cap). Note that there should not be any signs of the plastic ring melting during the procedure and certainly NO smoke!

Carefully fan the centre 90 degrees of the exposed ring at opposite sides for approx 30-45 sec each (NOT the area of the latches, just the this part of the ring). Then leave the ring for a couple of minutes before removing the tensioning object in the middle. The procedure will "realign" the plastic shape, and should maintain its new shape.

You can now test the gripping force by inserting the ring into the hood (best to disconnect the hood from the lens first), if the grip is sufficient the ring can be re-inserted into the cap. If not satisfied the procedure can be repeated with a slightly higher temperature or increased distance between the latches. Don't use excessive force when testing.

The cap should now have a much better grip. I can now lift the lens by the cap, previously the opposite was often not possible!

Note that the above procedure is done at our own risk.


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## Quasimodo (Jan 13, 2013)

iohansen said:


> The problem with the cap is that the it uses two latches on the cap to fix it to the hood (using inside ridges at the end of of the long hood petals). These latches does not have enough force to keep the cap in place, indeed it is possible to drop the cap merely by shaking the lens/hood/cap (if it's in the "wrong" position). So how to increase the force provided by the latches?
> 
> This is relatively easy, the cap latch mechanism is a single plastic construction that can be removed (this relates NOT to the hood with its single release button). This is done by pushing one of the latch buttons all the way in, towards the centre of the cap, and then gently pressing it down into the cap, it should release/pop out of the inside grooves.
> Repeat for the opposite latch. The entire latch ring can now be removed. It has the shape of a slightly flattened circle with the latches at opposite ends. At the inside of the push buttons one can see the latch ridges that interlocks with the hood.
> ...



You don't happen to reside in Norway? I have one here


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## iohansen (Jan 14, 2013)

Indeed, I do reside in Norway (Kongsberg to be exact).


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## AudioGlenn (Jan 15, 2013)

iohansen said:


> The problem with the cap is that the it uses two latches on the cap to fix it to the hood (using inside ridges at the end of of the long hood petals). These latches does not have enough force to keep the cap in place, indeed it is possible to drop the cap merely by shaking the lens/hood/cap (if it's in the "wrong" position). So how to increase the force provided by the latches?
> 
> This is relatively easy, the cap latch mechanism is a single plastic construction that can be removed (this relates NOT to the hood with its single release button). This is done by pushing one of the latch buttons all the way in, towards the centre of the cap, and then gently pressing it down into the cap, it should release/pop out of the inside grooves.
> Repeat for the opposite latch. The entire latch ring can now be removed. It has the shape of a slightly flattened circle with the latches at opposite ends. At the inside of the push buttons one can see the latch ridges that interlocks with the hood.
> ...



Interesting. I wonder if you can get a similar affect by just using some tape. I find I can fix 80% of the stuff around the house with tape and/or WD-40! haha oddly enough, my wife said that's what her mom used to say about her dad while growing up.


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## Invertalon (Jan 15, 2013)

When I rented this lens I never had an issue with the lens cap. It stayed on until I removed it with the tabs. It never once popped off on me. Maybe they loosen up or something over time?


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## AudioGlenn (Jan 26, 2013)

so I've had about a month with this lens. I took it to the NAMM show yesterday. While I walk around, I try to keep the lens cap on to help protect the exposed front element. 

I went to take a leak with my camera around my neck... of all the disgusting places for this lens cap to randomly come off.... dammit, the cap fell right into the URINAL...while I was peeing on it. LOL

I rinsed it off in the hottest water available but DAMN... really. looks like I'm super gluing this fu&%#r onto the hood. Maybe I should get a generic/off-brand hood and cap. Any one know if there are any generic hoods/caps available for this lens?


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## bfawcett (Mar 31, 2013)

Best solution is to get self adhesive velcro or felt at fabric store and attach it to the top and bottom of 15mm hood so the the cap has resistance from falling off. Never tried it but I will.


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## infared (Jun 4, 2017)

If anyone is interested I created a very simple solution to address this problem. It does not involve the Canon packaging paper, rubber bands or electrical tape, or anything inconvenient or silly. It involves no special tools. Just a hobby knife and one tiny, rubber bumper. My solution is totally unnoticeable, i.e. Lens and cap "appear" exactly as purchased and "appear" to function in the normal manner.. You have to be mildly handy. It takes max 5-10 mins. It damages nothing and it can be removed easily if need be.The lens cap functions exactly as designed but unlike the original design, my fix makes the cap grip very tightly and it is at least 10x more secure. Mine fell off constantly before the fix. Now is is MUCH more secure. 
I am too lazy to take photos, etc...unless someone wants the info. Contact me here:
[email protected]

What is annoying is that Canon could easily make this product better with almost no effort and offer actual protection for an exposed element on a $1200 lens. DUH.


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## pwp (Jun 4, 2017)

As a slight divergence, here's a tip for anyone whose lens back caps and body caps become loose. With time and use, they all do. I just get a gas cigarette lighter and carefully lick the flame against the lugs inside the cap. As soon as you can see them beginning to expand with the heat, stop. Don't breathe the smoke. 

Now your caps will be nice and firm for another few years. I've been doing this for decades. ;D

-pw


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