Another case of the E-M5iii tripod mount failing

Started 4 days ago | Discussions thread
cba_melbourne Senior Member • Posts: 1,745
Re: Another case of the E-M5iii tripod mount failing

Impulses wrote:

cba_melbourne wrote:

whumber wrote:

Impulses wrote:

It's always seemed odd to me that Oly continues to push the tripod socket so close to the front edge of the body tho.

Yeah, I've never understood that either.

There is a reason for that though.

The greatest mechanical strength, is deigned to be between the lens mount and the sensor assembly. Any flex in this area would cause optical problems. The sensor plane needs to be perfectly aligned and orthogonal to the lens axis. You do not want focus to change with camera flex, you do not want centering issues. So this area is made strong and stiff and usually with metal.

The tripod mount anchoring is a highly stressed point, and it makes very much sense to solidly anchor this to the strongest part of the camera, which is this frame formed between sensor and lens mount.

On a DSLR this point is further back, because DSLR's have a larger rigid chassis formed by the mirror box between sensor and lens mount. Mirrorless cameras do not have this mirror box chassis.

Now, if a mirrorless camea is made with front and rear covers of metal, both the lens mount and the sensor assembly are screwed directly onto to the metal front cover. The front and rear cover are folded over and joined at the bottom. And the tripod mount can be attached a little further back at the bottom and is still rigidly attached to solid metal.

If the camera is made with front and rear covers of plastic, the tripod mount must be attached to the very small metal area formed by the sensor assembly and the lens mount, and will necessarily end up further forward. Depending on design, this may still not be as strong, particularly when the folded over portions of the front and rear plastic covers are sandwiched between the metal tripod mount and the metal sensor assy/lens mount, as appears to be the case with the EM5.3.

Hope it makes sense, its hard to put into words... just got up and need a coffee now...

Makes a lot of sense, but why did they only start doing so relatively recently then? The original E-M5 had the tripod socket near the center of the bottom plate of the camera (front to back, I think it actually wasn't centered under the lens which is a different sort of silly)... Then it started shifting forward with the mk II, PEN-F, etc.

The original EM5 had a full magnesium chassis. That gives the designer freedom where to attach the socket, as the whole bottom is metal.

I think Pana started shifting it forward around the same time with the GX85 (look up pics of the GX7 by comparison, it was way farther back on my GF6 too), whereas older bodies had it more centered front to back (G7 onward started pushing it right to the edge for that series I think). On some of these bodies it's so far forward that it has to be closer to the mount than the sensor, not dead center between both. I dunno what else it may or may not interfere when shifted...

There is of course more to it. With very small cameras, there may be other reasons than just rigidity to chose a forward mounting point. A more central point may interfere physically with the sensor or shutter assembly or other components.

 cba_melbourne's gear list:cba_melbourne's gear list
Panasonic Lumix DMC-GM1 Panasonic Lumix DMC-GM5 Olympus E-M5 II Olympus PEN-F Olympus Zuiko Digital ED 9-18mm 1:4.0-5.6 +11 more
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