Niagar Falls Pic

Hi , recently I went to Niagara Falls, Canada and tried to capture the falls in the day time.
To achieve the photo graphic effect of the falls, I have reduced the shutter speed to 1/5 . I have used the Canon 24mm f/1.4 II USM lens.
Since the shutter speed is reduced the picture became too bright , so I have lowered the ISO to its lowest and increased the F value to the highest,still the pics are too bright and I could not get the smooth falls. Can some one advice how I can achieve it?
Thanks in advance

You need a neutral density filter - somewhere in the 3-6 stop range.

I was at Niagara Falls Summer of 2011. I was typically using a 6 stop ND filter, 1/2-1 sec shutter speeds, and f/11-22. I wished I had the 10 stop ND filter. I think Niagara Falls would look best at 2+ second exposure. I usually shoot small waterfalls and like the effect that you get with ~1/4 shutter speed. However, when I did this at Niagara, I didn't really care for the effect. I think it is because Niagara is so tall, you need to have enough time for the water to form a continuous streak and the smooth out some natural variation each falls has. The bigger the falls, the more time you need. At least, that is my thought.

So, I'd recommend a 10 stop ND filter from either B+W or someone like Lee (hearing good things, still need to try) for day shots. And, of course, a good tripod. For night shots, which can be spectacular, a CPL to a 3 stop ND filter is all you'd need. You may even be able to get away without a filter, but I am pretty sure I used one.

A few shots:
http://farm8.staticflickr.com/7024/6...9e938ffd_b.jpg
Falls IMG_2044 by kayaker72, on Flickr

This was 1 sec, f/20, ISO 100 6 stop ND filter

http://farm7.staticflickr.com/6214/6...411363ed_b.jpg
Falls IMG_2704 by kayaker72, on Flickr