Ever wondered how strong your lens mount is?

now just add a piece of straw to the front of the lens...

I think they didn't attach a tripod mount to the lens for nothing.... Also in panning it assures the focal centre is more close that of the lens than the camera.

You're a brave man, my 500 weighs about the same and there's no way I'd but that stress on the mount!

Why you don't try with the 1200 f/5.6 USM ?

joeseph wrote in post #17139924
now just add a piece of straw to the front of the lens...

Lol

It's not the mount that I'd be worried about, but wha it's screwed into. I could envision those screws pulling out from where the mount attaches to the body.

I really don't understand why one would mount a camera that way?

the lens mount IS part of the chassis, so yeah its pretty strong

It might not break, but you may well have bent something !

If your camera suddenly develops a very mild "tilt-shift" type effect, you have certainly damaged it.

Of course it will hold it. But after a while it can cause real bad things to happen to the mount.

Proof positive that just because you can, doesn't mean you should.

I took the lens mount off of my 3 pound 100-400 years ago. It works fine without it on my 7D. (But it's not near as heavy as your 400 2.8.. That is impressive

panicatnabisco wrote in post #17140019
the lens mount IS part of the chassis

only by virtue of 4 small screws... the top ones especially!

This is obviously not how the gear should be fitted to the tripod because of the huge imbalance making it very hard to work with.

But he mount has to be made very strong for the single reason that when the gear isn't on the tripod, then it has to support being carried which includes the stress of every footstep. And when people are hand-holding, they might sometimes need to get their left hand free to do something, in which case the lens mount has to take the weight.

The important thing here is that the mount should be able to support this static weight without damage. But it has quite limited safety marging for additional bumps. Let's say you losen the tripod head and the lens/camera suddenly falls forward until it reaches some stop. That will result in a huge impulse force on the mount. And then all bets are off.

Even if the mount looks fine it may develop microscopic cracks and fissures. This is called metal fatigue:
http://en.wikipedia.or​g/wiki/Metal_Fatigue

In the past, some air tragedy happened due to the fact that this phenomenon was not well understood at the time.

So looks fine doesn't mean its fine.