# Trouble mounting a new 24-70 II



## J.R. (Apr 22, 2013)

Hi,

My new 24-70 II arrived today. However, I am less than pleased with the difficulty I am having mounting the lens. The lens seems to require more effort while mounting it onto both the 5D3 as well as the 6D. While turning the lens I am almost feel a slight grinding while turning the lens to lock it in. 

I've never faced any such problem with any of my other lenses ... this doesn't seem to be a perfect fit for the cameras somehow. Anybody else face a similar problem? Suggestions .... 

Thanks in advance ... J.R. 

PS: I do have the option to return the lens if it doesn't work out. I'm kinda scared it'll mess up the bodies. I've just left it on the 5D3 for now (it is working fine).


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## Random Orbits (Apr 22, 2013)

Most likely a tolerance stack up issue. My 70-200 is a little loose with some play, and the 24-70 is much tighter. Try inspecting both sides of the mount (lens and camera side) to ensure that it is free of debris. If you bought it at a brick-and-mortar store, you could bring it back and try it with some other 24-70s to see if one of them "fits" your cameras better.


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## J.R. (Apr 22, 2013)

Random Orbits said:


> Most likely a tolerance stack up issue. My 70-200 is a little loose with some play, and the 24-70 is much tighter. Try inspecting both sides of the mount (lens and camera side) to ensure that it is free of debris. If you bought it at a brick-and-mortar store, you could bring it back and try it with some other 24-70s to see if one of them "fits" your cameras better.



Thanks. The mounts are absolutely clean and have no debris - all other lenses are mounting without a problem. 

My main concern is with the fact that I can almost feel the surfaces grinding against each other - no noise as such, just a general feel you get in your hands while locking the lens.

I have bought it from a local shop - I know the owner pretty well so it is easy to return it if need be. Sadly, I live in a small town and lenses such as the 24-70 II come up only on order and it is not possible for me to try it out with other copies of the lens.


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## Chris Burch (Apr 22, 2013)

Mine started out quite tight (more than my other lenses) but I haven't noticed it recently when changing lenses, so I am thinking it must have loosened up enough for me not to think about it any more.


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## Sporgon (Apr 22, 2013)

Hmm, in the 'good ol days' a quality camera lens mount was made from machined stainless steel. The mounts on my old high end Nikon film cameras are still _really_ tight.

As s/s is very hard it is difficult - or rather expensive to machine to fine tolerances, so the camera producers started machining the mounts from some sort of brass, which is quite soft relatively speaking, and electro-plated them. On a well used pro's camera you will often see the plating wearing off the mount where the surfaces mate together.

Theoretically a very tight fitting lens will create more wear, but as it is brass to brass, and very evenly mated surfaces its gonna take a long, long time.

Personally speaking, the tighter the better for me, so _I_ would be quite happy 

And looking on the bright side it's unlikely you'll have to join the 'my 24-70 fell off my mk3 and smashed' thread !


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## RAKAMRAK (Apr 22, 2013)

I too think it is just a tolerance issue. I do not remember which one, but I have used one lens on my cameras which also gave me a similar grinding feeling while mounting - as if there are some large grains somewhere which are rubbing against each other.

PS: I think it is my Tokina 12-24mm wide angle lens that gives me this feeling.


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## RGF (Apr 22, 2013)

I (we) would hope that with an lens as expensive as the 24-70II tolerances would be tight. Too bad we can not be a fly on the wall at Canon's QC meetings


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## Mt Spokane Photography (Apr 22, 2013)

Mine fits snugly as it should, pretty much the same as all my other lenses. Lens mounts are made to extreme small tolerances, a 1/10000 inch error can vary the tightness. If it doesn't loosen up after mounting it 10 or 20 times, you can ask the shop owner to have it serviced.


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## Dylan777 (Apr 22, 2013)

Sorry to hear that J.R 

Mine also has snug fit to 5D III, slightly tighter than 70-200. I do not feel "slight grinding" as you descrised though.

Ask for new copy if you not completely happy.


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## rpt (Apr 22, 2013)

Sorry to hear about that. Hope you get a good replacement.


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## J.R. (Apr 24, 2013)

Thanks for your replies. 

I tried a copy of the lens from a guy at the local photography club and it works fine. Seems like the lens I have has a problem. I've returned the lens to the dealer and he will provide a replacement ... will take about a week though. 

Cheers ... J.R.


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## Mt Spokane Photography (Apr 24, 2013)

J.R. said:


> Thanks for your replies.
> 
> I tried a copy of the lens from a guy at the local photography club and it works fine. Seems like the lens I have has a problem. I've returned the lens to the dealer and he will provide a replacement ... will take about a week though.
> 
> Cheers ... J.R.


 
That sounds like a good fix. I hope the replacement one works out.


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## Jeremy (Apr 24, 2013)

If you don't like how hard the 24-70 II is to put it on, just wait til you see how easily it can FALL OFF! Sorry all....still bitter after my little accident the other day. Sigh.


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