Lense Condensation problem Sony A700

It could be some kind of vapor around the camera that is condensing on the lens (doesn't necessarily have to be air), so if you keep it around any type of chemicals, or things like that, that could be your problem. The A700 is actually equipped with weather seals which are better than most of the SLR cameras around its level that I've seen out there. Canon's are definitely not as good, and Nikon is equal, if not a little worst, in my opinion. It could be that the two cameras you've had that the seal is broken, or just the environment that you're keeping the cameras in. Try keeping some dry salt around the camera, such as silicon packs that are in almost every packaged thing, to see if the problem keeps happening. The salt, or silicon pack, type devices help absorb moisture and keep it away from the camera. I think you may have just been unlucky and gotten two consecutive cameras with defective weather seals (or the same camera twice, depending on how you got it replaced). If all else fails, try a Nikon and see if you have the same problem.