Very slow shutter speed photography

Using a very slow shutter speed can give nice effects, especially with things like water or smoke. All movement becomes really smooth, giving a dreamy effect. I recently bought a Fotodiox Vizelex ND Throttle adapter, a Canon to Sony NEX adapter with built-in variable ND filter. According to their website, this adapter should solve the problem of uneven variable ND filters with wide angle lenses. Today I gave this adapter a first try in combination with another adapter, the Mirex Pentax 645 to Canon EOS tilt & shift adapter. That means I used a Pentax 645 75mm f/2.8 lens on my Sony A7R by stacking those two adapters. The results are quite nice, although I found that the ND Throttle does show a ‘hot spot’ in the center of the image when used at its full ND setting. If you do not go beyond about 9.5 however, the ND filter gives an even result. This allows you to use a shutter speed of about 8 seconds in full daylight. I think these kind of images are best in B&W.