I agree with K.Li, try them without the filters or with the telephoto. I took a lot of water drop pictures over the winter, mostly using my wife's 105mm nikkor. One key thing to doing these shots is consistency on where the water is dropping allowing the focus to stay pretty much at the same distance. I used an old cheapo tripod I had and a water bottle from a bicycle. Doing this had the water dropping in the same spot every time. I then used a pencil and placed it in the spot where the water was dropping and manually focused on it. Then fire away.