I haven't tried this, but if tempted I'd use the silicone gasket-making material as the sealer.
I'd use a "disposable" K-mount body covered with . . . hmm? . . .
- A 'SaranWrap' -type plastic film trimmed to the mount, or
- If "disposable enough", just Vaseline lub on the body/mount face to ensure separation, and
- Cellophane tape or some such to protect the area of the electrical contacts, etc.
I'd attempt to mold a custom gasket on the periphery of the male lens/TC mounts. A trial run with junker bodies and lenses might be useful. Excess gasket could be trimmed with a razor later.
But first, I'd see if properly sized silicone or rubber O-rings rolled onto the lens and body joints after assembly would provide enough protection just through the elastic fit.
In any case, unless you can attain a compression gasket fit between two smooth surfaces you risk liquid intrusion via capillary action. For this reason, I'd be more inclined to use a weather resistant cloth cover that wicked and diverted liquid away from joints than a plastic material that could channel moisture into a joint.
Consider that if conditions are really bad,
the environmental effects will negate any advantage of using a DSLR over a truly weather-proof P&S like the Pentax W-class cameras so you may just be better off to do the P&S thing for piece of mind if your DSLR isn't an "expendable" and insured working tool.
But I'm curious; I can't imagine wanting to shoot something in bad weather/snow/rain that's even viewable at a distance that a TC would be needed on a 300mm tele lens anyway? Sounds like a good time to be enjoyin' a bowl of chili an' a beer in front of the fireplace unless the pay for that shoot is really great.
H2
Last edited by pacerr; 09-29-2010 at 09:50 PM.