Weight rating/limit of the EF mount

eiker_ir

eiker_ir

Well-known member
hi, just wondering if anyone knew what the recommended weight limit without any support would be for the EF mount used in the 7D, 60D, T3i, etc.


I currently use a light clip on matte box with one 4x4 filter but may need to stack 2 in the near future and just wanted to make sure that i stay withing the recommended range and that i won't put much stress on the mount.
 
Well it's probably hard to define because it's not about simple "weight", it's a much more complex combination of factors. For example, putting your matte box with a glass filter onto a (pysically) longer lens like a Sigma 50-500 will add a lot more stress at the Lens mount than if it was mounted to a short, stout lens like a 50mm f1.4. The further away the weight is from the mount, the more stress it will add. It also depends on the construction of an individual lens. If the thread on the lens is part of the inner barrel construction rather than the outer body, then the lens will absorb more of the stress - this is obviously bad for the lens but means there is less strain on your mount.

There's many other things that can affect the strain on the lens mount (and it is different for each camera model too due to different materials, construction, etc), but as long as you are sensible you shouldn't do any damage. Maybe post a pic of your setup and people will be able to tell you whether or not ii is indeed 'sensible'.
 
I'm not actually using any big/heavy zoom lenses at the moment, i'm using smaller primes most of the time. It was mostly curiosity about the subject which seems like good information to know in the future.

It peaked my interest because i've seen mentioned in other threads about how the Micro 4/3 mount was considered kinda "weak" and was wondering how the EF mount compared to it.
 
The 7D has an magnesium chassis and is tough.

The 60D is plastic but also tough. with a 70-200mm IS L II (1.6KG) no problem. Add a 2x teleconverter and there is just detectable (to my hands) flex. Add a 2nd 2x converter (dont' laugh - this works fine for video in good light) and flex is obvious when handling - but the lens will be supported anyhow by the lens foot.
 
Yeah, as was said, "be sensible" is good advice. There's a reason we aren't constantly hearing about people who broke their lens mounts: it does not happen often. Canon has stopped making them out of plastic on the consumer models, and pretty much any lenses that would need them come with tripod mounting rings. Matte boxes are fairly lightweight. You should be fine.
 
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