Tiffen's 55mm Ultra Contrast 1/2 Glass Filter uses the surrounding ambient light, not just light in the image area, to evenly lighten shadows throughout. Use this filter where contrast control is needed without any other effect on sharpness or highlight flare being apparent.
Works with surrounding ambient light
Captures details lost in shadows
Lowers contrast evenly throughout image
No flare or halation
Lets you "see" more