#12 is the most interesting of these, but they're all quite 'shiny' for my tastes. I like the spareness of #3, but #7 is too minimal. (It's not much more than an oval.) It may be that I'm thinking too much of a watermark, but I'm looking for a logo that is simpler, less 'over-produced'.
I like #17. It's subtle and definitely moving in the right direction. I like the 'flatness' of #18, but it's too literal for my tastes. It says 'lens' but not 'craft'. #19 is very nice, but the colors are a little too bright... I would make them darker and/or more saturated. Check out the colors in my photography at http://lenscraft.smugmug.com/ ... I'm also curious as to how this would work as a watermark...