Bump map disappears at particular view angle

[Sacha]

Have you tried using a V-Vray bump material? Throw your base material with no bump in, then put the texture to the map slot and render. I notice if I'm not happy with the bump on the V-Ray shader I use this and get totally different results.

This is with the latest stable build.

I haven't tried that before. now after playing a bit with it in cunjunction with the delta scale I got, what I wanted. Just to be shure what´s going on there I tried some different shots with different settings. Also again with the regular bumpmaps. And suddenly also the regular bumps worked by just tweaking the delta scale, what really didn't work earlier. So I have no idea why it works now. Maybe it's the latest nightly. Anyway thanks a lot to all for your assistance!
And scott, it seems like the method you recommended makes no difference to the regular one with the latest nightly build. Tested both and got exactly the same results...

again.. thanks a lot!!
aqua