Test photos of ND (Neutral Density) filters

I bought two ND filters from TIFFEN: ND.3, ND.6 for 58mm lens.
I will ND filters to prevent or reduce over exposure problem of outdoor photos during the day.

Camera: Canon EOS DIGITAL REBEL XS
Whitebalance : Manual
Light Source : Daylight

IMG_0687.JPG, 2012:10:25 11:54:32, f/11.0, 0.0031(1/320), ISO 100

Naked lens

IMG_0688.JPG, 2012:10:25 11:56:36, f/8.0, 0.0031(1/320), ISO 100

ND.3 filter is on

IMG_0689.JPG, 2012:10:25 11:59:13, f/5.6, 0.0025(1/400), ISO 100

ND.6 filter is on

IMG_0691.JPG, 2012:10:25 12:01:47, f/4.5, 0.0031(1/320), ISO 100

Stacked ND.3 and ND.6

My room with natural light. There is slight tone changes caused by ND filters. I doubt I ever use ND filters in indoor setting.

IMG_0696.JPG, 2012:10:25 12:15:13, f/8.0, 0.500(1/2), ISO 100

Naked lens

IMG_0695.JPG, 2012:10:25 12:13:04, f/8.0, 1.000, ISO 100

ND.3 filter is on

IMG_0694.JPG, 2012:10:25 12:10:42, f/8.0, 1.300, ISO 100

ND.6 filter is on

IMG_0693.JPG, 2012:10:25 12:08:34, f/8.0, 2.500, ISO 100

Stacked ND.3 and ND.6 filters