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I've been wondering why I've never seen any official specifications of the maximum allowed torque that can be exerted upon lens mounts. It seems to me like a very useful specification, but I can't seem to find it from any manufacturer. This answer indicates that there might be no specifications for Nikon mounts. Are there really no manufacturer that publish these specification of their mounts?

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I'm sure each manufacturer has a specification for the amount of force along several axes that their lens mounts need to be able to accommodate, but they don't seem to publish that data.

They are probably not published because in the real world it is a specification that is not practically needed. It is fairly simple to understand why. Which to support (camera or lens?) is a decision based not on the load capacity of the lens mount, but rather on which allows the user to keep the camera/lens balanced and more stable while shooting. The transition to primarily supporting the lens should occur well before the limits of the camera's lens mount is reached. When lenses have less mass than the body they are attached to they should be supported by the body. When lenses weigh more than the body the body/lens combination should be supported by the lens. You do this not because of the load capacity of the lens mount, but rather to maintain balance and stability when shooting.

Lens mounts are not only built to support the weight of the pieces they hold together, but to handle the force those pieces can place on the mount when dropped from small distances. The static weight of a lens would need to be several multiples of the weight of a body before the mount couldn't handle it. Further, to the best of my knowledge the specification, for example, of the Canon EF/EF-S mount is exactly the same regardless of whether the camera in question is a Rebel SL1 (14.4 oz.) or a 1D X (54 oz.).

  • Side note, which to support is a little more complicated than which weights more, but rather which will exert more force on the mount. A 3 pound lens that is over a foot long is going to exert more strain on the mount than a 6 pound camera body that is only an inch or two deep thanks to the leverage the lens exerts. The basic observation that the camera body limits the most torque that should be applied holds though. – AJ Henderson Jun 30 '14 at 13:52
  • @AJHenderson Lens mounts are not only built to support the weight of the pieces they hold together, but to handle the force those pieces can place on the mount when dropped from small distances. The static weight of a lens would need to be several multiples of the weight of a body before the mount couldn't handle it. There aren't that many three pound (or lighter) lenses over a foot long, at least when retracted. Lenses that long or longer tend to be much heavier than the bodies they are attached to. And even if you did have a 3#/12" lens, ALL of the weight would not be @12". – Michael C Jul 1 '14 at 3:12
  • Further, to the best of my knowledge the specification for the Canon EF/EF-S mount, for example, is exactly the same regardless of whether the camera in question is a Rebel SL1 (14.4 oz.) or a 1D X (54 oz.). – Michael C Jul 1 '14 at 3:16
  • Which to support (camera or lens?) is a decision based not on the load capacity of the lens mount, but rather on which allows the user to keep the camera/lens balanced and more stable while shooting. The transition to primarily supporting the lens should occur well before the limits of the camera mount is reached. – Michael C Jul 1 '14 at 3:20
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    don't get me wrong, I wasn't saying that it would or wouldn't be a problem, just pointing out that there is more to it than simply which is heavier when you are deciding which to support and which is being supported by the mount. The edit is even better than my original point was though. I was only objecting to your former last sentence "When lenses weigh more than the body the body/lens combination should be supported by the lens." – AJ Henderson Jul 1 '14 at 3:45
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Nikon Support tells me they issue no such specifications and I should always support the camera by the lens if the lens seems heavy.

Have they forgotten about tripods? If the lens cannot take a tripod collar, it has to be supported by the camera body or some awkward gadget such as Manfrotto's. So when is the Manfrotto gadget necessary?

I think it is shortsighted of them not to offer tripod collars for heavy lenses.

  • This seems more like a repetition of the question, or a complaint, than an answer. – mattdm Apr 30 at 19:27
  • @mattdm - I'm not sure how this isn't an answer to the question. It goes beyond just answering, but it clearly indicates the answer (at least for Nikon) is that there is no official specification. – AJ Henderson May 6 at 17:04
  • @AJ The question already indicates that the answer is negative for Nikon. – mattdm May 6 at 17:06
  • The question indicates another answer that says their might not be. I suppose it isn't an answer that no manufacturers do, but I'm not sure anyone can really say that given that there could always be some small manufacturer that does. – AJ Henderson May 6 at 17:08

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