The problem with the ND 3.0 is I should have gotten a ND 4.0, however focusing is a problem with the ND 3.0, and often I have to remove it to focus, so a 4.0 would definitely be difficult to use. I mostly use the filter at sunset when the light is diminished anyway, as it is not effective during bright daylight.

File Name                       : IMG_4452.jpeg
Date/Time Original              : 2008:10:10 18:00:46
Camera Model Name               : Canon EOS 30D
Aperture Value                  : 13.0
Shutter Speed Value             : 1.3
ISO                             : 100
Flash Exposure Compensation     : +1
Shooting Mode                   : Aperture-priority AE
Metering Mode                   : Evaluative
Focus Mode                      : One-shot AF
Exposure Compensation           : -1/3
Lens Type                       : EF24-70mm f/2.8L USM
Focal Length                    : 46.0 mm (35 mm equivalent: 71.9 mm)
Field Of View                   : 28.1 deg
File Size                       : 297 kB
Exif Image Width                : 1280
Exif Image Height               : 854
Quality                         : Fine
Drive Mode                      : Self-timer Operation
Flash                           : Off
White Balance                   : Auto
Mirror Lockup                   : Enable
Contrast                        : +2
Sharpness                       : 3
Saturation                      : +3
Color Tone                      : +1
Camera Body No.                 : 1420901948