Did you ever ask yourself why can we look at the sun during sunrise and sunset while it is too bright to look at during mid-day? See the illustration below. It is all about the Atmosphere being a powerful filter, and the distance the light travels through the filtering atmospheric layers.
A similar effect takes place when using a neutral density (ND) filter on a wide angle lens: the distance traveled by objects at the far ends is much greater than frontal objects, thus causing vignetting.
Hence the darker corners.
Shot with Fotoman 617 using Apo Symmar 150mm f5.6, B+W 3.0 stops MRC filter on Color negative film. Available at www.yaalherman.com
- Use slow film
- Try a Polarizing filter (1-2 stops only)
- Manually expose the corners only as you’d burn the printing paper in the darkroom.