Suntouch: You may be on something here....

My engineer friend (him with the falling-off lenses) studied the camera pin and objective socket (see first two pictures) that are part of the locking system at close range. On his cameras, the pin is tapered but more importantly, the lens socket into which the pin normally fits shows some damage (metal deformation), presumably due to gradual wear and tear associated with the weight of the lens hanging from the camera body. I don't know whether this would be enough for the lens to detach from the camera, but this may be the case.

And here is the thing: I recently purchased an Olympus EM1 Mark II camera and on this new model, the pin has been re-designed so that it is now cylindrical and not tapered - see third picture. No way to know for sure, but the Olympus guys may have discovered that the design of the old (tapered) pin is faulty (i.e., damages the socket) and so modified it so it can (hopefully) accommodate relatively heavy lens without damaging the socket. Time will tell!

Very insightful and constructive comment, billnikon. Thanks.

RWR: As mentioned in original post, this happened to a friend of mine and so I relayed what he indicated to me on this discussion forum. I never had this happen personally and my initial reaction was the same as yours...

A friend of mine owes two camera systems: An Olympus EM5 II that he uses with an Olympus 300 mm lens, and a Panasonic GX85 that he uses with a Panasonic/Leica 100-400 mm.

He indicates that in the recent past, and using one of his rigs and at another time the other rig, he had the lens just separate from the camera and hit the pavement while he was carrying his equipment using a shoulder strap. These incidents did fortunately not cause fatal damage - just a couple of dents to the lens hoods. Being a mechanical engineer, he seems 100% sure that in both cases, the lenses were initially securely fastened (clicked into place) to the camera bodies, and so can't come up with any good explanation for what happened that caused the lenses to "spontaneously" separate from the camera bodies. I can't understand either how this could happen based on the mechanical system that attaches lenses to camera bodies... Has anyone experienced this kind of mishap?

Topaz Studio can be downloaded for FREE and is definitely worth trying - works great on RAW and JPEG files, and for a small fee you can add a bunch of useful plugin modules (that Topaz calls "adjustments"), i.e., you can customize the program based on your photo-editing needs and don't have to pay for all kinds of functions for which you have no use.

A PRO edition can be purchased that includes all these adjustments. The program also works seamlessly with all the Topaz modules, e.g., Topaz Impressions, DeNoise, and many others. There really is no good reason to pay for a photo-editing program without first trying Topaz Studio.

I also live in Phoenix and do a lot of wildlife photography (esp. birds & insects). I just purchased the new Olympus OM1 Mark II camera and the Olympus 40-150 F2.8 Pro lens, along with their 1.4 teleconverter.

This equipment is definitely worth looking into: solid build, lots of shooting options, super stabilizer system, almost instantaneous autofocus, and outstanding lens quality. This being a mirror-less camera, it is also lighter and more portable than the traditional big rigs, but not at the cost to quality.