My favorite disaster was when I knocked my converted, full spectrum D200 + UV-Nikkor 105/4.5 + BaaderU filter + RRS Ground Pod into a vernal frog pond. It was probably the frogs' doings because they resented the photographic intrusion. Frogs can be tricksters.
The D200 went in backside first, so I thankfully managed to grab the UV-Nikkor just before it was going to submerge. The camera came up soaking wet of course and covered in duck weed. I immediately removed the lens & card and opened up all doors and windows to shake the water out and off. Later I did the oven thing to try to dry out the D200, but to no avail. The D200 no longer worked.
When I sent the D200 in for analysis and possible repair, Nikon Melville insisted on replacing the sensor to "repair" the conversion - which I did
not want them to do. At that time they wouldn't budge on this issue, so I "refused" the repair, and Nikon sent the D200 back to me. However the cam now worked! I don't know why it worked, but we don't look Gift Horses in the mouth, right? I still have that cam.
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My other worst disaster was seeing my D3S + 24-70/2.8G AFS (old version) + RRS Ground Pod fly over the edge of a spillway wall and land on granite rocks about 7 feet below. Miraculously the D3S still turned on when I retrieved it, but the lens front was bent and the helicoid stuck. There were also scuffs and minor dings on everything.
I'm still surprised at how little damage there was overall from this big fall. Everything must have to land just right for such an escape from major breakage? I sent D3S & lens to Nikon for full checkover and repair. And RRS gave the little tripod a checkover, adjustment & cleaning.
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Dropped the D300 body onto my brick patio and watched it bounce. A scuff mark on the bottom corner, no damage.
Saw the same D300 + lens roll out of the back of an SUV and hit the deep sand/dust of the Mohave Desert floor. Thankfully it missed the gravel and rocks.
Stepped on a $345 BaaderU filter (in the same desert) when I lost my balance in some gravel. The fracture shards were interesting and very sharp. Cut my hand a bit. I couldn't leave the shards there because of all the little critters.
Recently heard the D600 and rather expensive Coastal Optics 60/4.0 lens hit the same desert floor with a big thump when the cam managed to un-engage itself from the quick release lock on the tripod. I'm not sure how that happened, but it was scarey. No damage thankfully. Lots of dust.
Killed two D7000 in a row trying to convert them myself. This after several successful conversions.
Have
not tried this since. Enough do-it-yourselfies for me. Now I let the conversion shops earn their pay.