Long exposure of receding wave

Camera: Canon 5D, Lens: Canon 17-40 F4, Focal Length: 20mm, Aperture: f22, Shutter speed: 5 Seconds, Shooting Mode: Aperture Priority, Picture Style: Standard, Other: Polarizer, Tripod, Cable release, mirror lock-up.

I was at the Oregon Coast (Manzanita) and it was an overcast day with really flat light. I was bored so I went down to the beach with my camera to see if I could find anything good to photograph. All I could find that was remotely interesting was the waves running up the beach. So I decided to play around with some long exposures and see what I could come up with. I started-off trying to capture the wave running-up the beach, but this didn't create any compelling results, so I switched to shooting the waves as they receded, this did produce some interesting results. I used the combination of the following 3 techniques to allow this very long exposure: ISO 50 (make the sensor as insensitive to light as possible), an aperture of f22 (tiny hole) and a polarizer; this combination allowed for the long 5 second exposure. This photo represents my favorite of the 50 of so frames to I took. I like the way the receding foam curves around the slight bulges in the sand. My shoes and pants got soaked during this shoot. Here are the details of why I choose each setting/piece of gear (in order of importance):

• Aperture of f22: I set the aperture as small as possible to let in as little light as possible, which allowed me to have long exposure.
  
• Polarizer: The only reason I used the polarizer is reduce the amount of light entering the camera, so I could leave the shutter open longer.
• ISO 50: This doubled the duration that the shutter was open vs. using ISO 100 [some folks say you shouldn't shoot ISO 50 on Canon DSLR because you lose contrast, but it worked-out OK on this shot.]
• Shooting Mode of Av: I wanted to specify the f22 aperture, and let the camera figure out the shutter-speed.
• 5 Second exposure: I needed a long exposure to capture the motion of the receding wave. The camera selected this shutter-speed automatically.
  
• Exposure compensation of +2/3: The camera's built-in meter was making the scene too dark, so I dialed-in +2/3 exposure compensation.
• 20mm focal length: This focal length allowed me to see enough of the scene to make it interesting. [If I was using a Canon crop-DSLR, I would have used the Canon 10-22 lens.]
  
• Tripod: I needed the tripod to hold the camera steady for this long exposure.
• Cable release of the shutter: My cable release of the shutter eliminated any 'shake' from the pressing & releasing of the shutter button. (You can achieve the same result using the camera's built-in timer, but if you're taking 20 or 30 images, the timer is a slow process.)
  
• Mirror lock-up: For longer exposures, the 'slap' of the mirror swinging up can cause slight image blurring. Mirror lock-up 'locks-up' the mirror on the first press of the shutter release and the exposure the photograph with the second release of the shutter. You can 'enable/disable' mirror lock-up in custom functions. (I only worry about 'mirror-lockup' if I'm trying to make the highest-quality landscape photos.)
  
• Cable release of the shutter: My cable release of the shutter eliminates any 'shake' from the pressing & releasing of the shutter button. (You can achieve the same result using the camera's built-in timer, but if you're taking 20 or 30 images, the timer is a slow process.)

A lot of the 'process' described above is the process I use for almost all my landscape photos.