loosening stuck F*300mm lens hood

**Hornet** · 03-13-2019, 03:15 PM

Somehow I managed to get the built on lens hood of the F300 stuck in the extended position. Probably it is cross-threaded. I've tried putting as much force into turning it with my hands as I can and have even tried using 2 belt wrenches to increase the leverage but nothing - doesn't even give the slightest indication of movement.

Does anyone have any tricks up their sleeve for this problem? Maybe a safe thread lubricant to try or something else non-damaging I can try?

Any suggestions are welcome and if one works I'll post the solution.

**richfam** · 03-13-2019, 04:42 PM

Originally posted by Hornet

Somehow I managed to get the built on lens hood of the F300 stuck in the extended position. Probably it is cross-threaded. I've tried putting as much force into turning it with my hands as I can and have even tried using 2 belt wrenches to increase the leverage but nothing - doesn't even give the slightest indication of movement.

It might not be cross-threaded: I remember that my F* 300 hood became stuck in the extended position; I had bought the lens new and it was probably less than a year old at that point. I resigned myself to just leaving it that way, as I wasn't about to try to force it... but eventually it came loose on its own. My guess is that it was likely a temperature change that allowed it to come free; but whether it was the lens warming up or cooling down I couldn't say.

So, before you try anything drastic, just keep working at it and maybe you'll get lucky like I did (I believe it was several weeks before my hood finally loosened up).

I eventually learned to NEVER tighten the lens hood in either extended or retracted position, because the design is so prone to locking up if you do. Always make sure that the hood can turn freely at either position, and you'll never have the problem again.

**Hornet** · 03-13-2019, 06:12 PM

HI Richfam - good to know that this has happened before and it "resolved itself". Temperature change might be the key so I may try cooling it down in the fridge or warming it up in the sun for a while and see if that works. You can bet I won't ever tighten it too far again.

**psoo** · 03-13-2019, 06:28 PM

I guess that the lens hood has a male thread that screws into the lens which has a female thread. If so, you could try cooling the hood with a small bag of ice so that as it cools it will shrink and loosen itself from the lens. I think it's worth a try. If you heat or cool both the lens and hood at the same rate, then it may not work.

**garywakeling** · 03-14-2019, 01:27 PM

How about putting a bit of warmth around the hood itself with some hand warmers and that might give enough expansion? On mine it can sometimes feel a little tight even just sliding it from the closed to open end, the tolerances feel quite tight, good luck,

**Hornet** · 03-16-2019, 05:49 AM

Thanks Gary for the hand warmer suggestion. I may try to use cooling on the end of the lens barrel while applying the hand warmers to the hood to maximize the contraction and expansion effect.

**psoo** · 03-16-2019, 11:25 AM

Originally posted by Hornet

Thanks Gary for the hand warmer suggestion. I may try to use cooling on the end of the lens barrel while applying the hand warmers to the hood to maximize the contraction and expansion effect.

Hi Hornet. Cooling the lens and warming the hood will tend to tighten the hood against the lens, I think. If this does't work, try the reverse since it should loosen the hood as the lens expands. Good luck.

**Hornet** · 03-16-2019, 02:18 PM

Psoo - this built-on hood of the F300 fastens opposite to how a typical lens hood would screw into filter threads. The threads are on the outside of the barrel and the hood surrounds it with threads on the inside. Hence cooling the barrel would shrink it away from the surrounding hood.

**Hornet** · 04-08-2019, 04:54 PM - **2 Likes**

Finally! After several times trying using cold/hot and rubber belt wrenches, the thing that worked was to very lightly pry the gap between barrel and hood with a table knife then the rubber belt wrenches. My assumption is that the prying disengaged the stuck or cross-threaded threads enough to allow the two pieces to move.

Thanks to all who answered this thread (no pun intended)

**garywakeling** · 04-09-2019, 03:39 AM

Originally posted by Hornet

Finally! After several times trying using cold/hot and rubber belt wrenches, the thing that worked was to very lightly pry the gap between barrel and hood with a table knife then the rubber belt wrenches. My assumption is that the prying disengaged the stuck or cross-threaded threads enough to allow the two pieces to move.

Thanks to all who answered this thread (no pun intended)

Great news, enjoy taking photos with this wonderful lens

03-13-2019, 03:15 PM	#1
Hornet Site Supporter Join Date: Sep 2007 Location: Victoria, BC, Canada Photos: Gallery Posts: 167	*loosening stuck F300mm lens hood** Somehow I managed to get the built on lens hood of the F300 stuck in the extended position. Probably it is cross-threaded. I've tried putting as much force into turning it with my hands as I can and have even tried using 2 belt wrenches to increase the leverage but nothing - doesn't even give the slightest indication of movement. Does anyone have any tricks up their sleeve for this problem? Maybe a safe thread lubricant to try or something else non-damaging I can try? Any suggestions are welcome and if one works I'll post the solution.

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03-13-2019, 04:42 PM	#2
richfam Site Supporter Join Date: Oct 2017 Location: Lindsborg, Kansas Photos: Gallery Posts: 66	Originally posted by Hornet Somehow I managed to get the built on lens hood of the F300 stuck in the extended position. Probably it is cross-threaded. I've tried putting as much force into turning it with my hands as I can and have even tried using 2 belt wrenches to increase the leverage but nothing - doesn't even give the slightest indication of movement. It might not be cross-threaded: I remember that my F* 300 hood became stuck in the extended position; I had bought the lens new and it was probably less than a year old at that point. I resigned myself to just leaving it that way, as I wasn't about to try to force it... but eventually it came loose on its own. My guess is that it was likely a temperature change that allowed it to come free; but whether it was the lens warming up or cooling down I couldn't say. So, before you try anything drastic, just keep working at it and maybe you'll get lucky like I did (I believe it was several weeks before my hood finally loosened up). I eventually learned to NEVER tighten the lens hood in either extended or retracted position, because the design is so prone to locking up if you do. Always make sure that the hood can turn freely at either position, and you'll never have the problem again.

03-13-2019, 06:12 PM	#3
Hornet Site Supporter Join Date: Sep 2007 Location: Victoria, BC, Canada Photos: Gallery Posts: 167 Original Poster	HI Richfam - good to know that this has happened before and it "resolved itself". Temperature change might be the key so I may try cooling it down in the fridge or warming it up in the sun for a while and see if that works. You can bet I won't ever tighten it too far again.

03-13-2019, 06:28 PM	#4
psoo Site Supporter Join Date: Jan 2012 Location: Long Island, NY Posts: 412	I guess that the lens hood has a male thread that screws into the lens which has a female thread. If so, you could try cooling the hood with a small bag of ice so that as it cools it will shrink and loosen itself from the lens. I think it's worth a try. If you heat or cool both the lens and hood at the same rate, then it may not work.

03-14-2019, 01:27 PM	#5
garywakeling Site Supporter Join Date: Jul 2011 Location: Melbourne Photos: Gallery \| Albums Posts: 774	How about putting a bit of warmth around the hood itself with some hand warmers and that might give enough expansion? On mine it can sometimes feel a little tight even just sliding it from the closed to open end, the tolerances feel quite tight, good luck,

03-16-2019, 05:49 AM	#6
Hornet Site Supporter Join Date: Sep 2007 Location: Victoria, BC, Canada Photos: Gallery Posts: 167 Original Poster	Thanks Gary for the hand warmer suggestion. I may try to use cooling on the end of the lens barrel while applying the hand warmers to the hood to maximize the contraction and expansion effect.

03-16-2019, 11:25 AM	#7
psoo Site Supporter Join Date: Jan 2012 Location: Long Island, NY Posts: 412	Originally posted by Hornet Thanks Gary for the hand warmer suggestion. I may try to use cooling on the end of the lens barrel while applying the hand warmers to the hood to maximize the contraction and expansion effect. Hi Hornet. Cooling the lens and warming the hood will tend to tighten the hood against the lens, I think. If this does't work, try the reverse since it should loosen the hood as the lens expands. Good luck.

03-16-2019, 02:18 PM	#8
Hornet Site Supporter Join Date: Sep 2007 Location: Victoria, BC, Canada Photos: Gallery Posts: 167 Original Poster	Psoo - this built-on hood of the F300 fastens opposite to how a typical lens hood would screw into filter threads. The threads are on the outside of the barrel and the hood surrounds it with threads on the inside. Hence cooling the barrel would shrink it away from the surrounding hood.

04-08-2019, 04:54 PM - 2 Likes	#9
Hornet Site Supporter Join Date: Sep 2007 Location: Victoria, BC, Canada Photos: Gallery Posts: 167 Original Poster	Finally! After several times trying using cold/hot and rubber belt wrenches, the thing that worked was to very lightly pry the gap between barrel and hood with a table knife then the rubber belt wrenches. My assumption is that the prying disengaged the stuck or cross-threaded threads enough to allow the two pieces to move. Thanks to all who answered this thread (no pun intended)

04-09-2019, 03:39 AM	#10
garywakeling Site Supporter Join Date: Jul 2011 Location: Melbourne Photos: Gallery \| Albums Posts: 774	Originally posted by Hornet Finally! After several times trying using cold/hot and rubber belt wrenches, the thing that worked was to very lightly pry the gap between barrel and hood with a table knife then the rubber belt wrenches. My assumption is that the prying disengaged the stuck or cross-threaded threads enough to allow the two pieces to move. Thanks to all who answered this thread (no pun intended) Great news, enjoy taking photos with this wonderful lens

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