What went wrong?
Every frame has dark corners
Camera
What you're seeing
The corners or the whole edge of each frame print or scan darker. Sometimes the corners are hard-edged and almost black, sometimes it is a soft fall-off.
Check this first
Check this first
Note whether the dark corners are sharp-edged or soft, and whether you used a hood, filters or a wide-angle lens.
Likely causes, most common first
- 01
Hood or filters cutting into the picture
Common- How to tell
- Hard-edged, very dark corners that appear only with a particular hood, a thick filter or stacked filters, and are worst on wide-angle lenses.
- Test it
- Shoot the same plain scene with and without the hood and filters. If the corners clear without them, this is the cause.
- The fix
- Use the hood made for that lens, one thin filter at a time, and take filters off wide-angles where you can.
Sources RED Digital Cinema, Lens vignetting; Nikon (scan: butkus.org), Nikon FM2 (FM2N) instruction manual (specifications)
- 02
Natural or optical fall-off of the lens
Common- How to tell
- Soft, gradual darkening towards the corners, strongest wide open and on wide-angle lenses. It eases when you stop down.
- Test it
- Photograph a clear sky at full aperture and at f/8. If the corners brighten at f/8, it is the lens's normal fall-off.
- The fix
- Stop down two stops or more when even corners matter.
- 03
Lens made for a smaller format
Occasional- How to tell
- A dark ring or circle round the whole image that does not improve when you stop down. Common when adapting lenses, or using a lens made for digital crop sensors on a 35mm film body.
- Test it
- Check what format the lens was designed for. Nikon, for example, says DX lenses are for digital SLRs and cannot be used on 35mm bodies.
- The fix
- Use a lens designed for your film format.
Sources RED Digital Cinema, Lens vignetting; Nikon (scan: butkus.org), Nikon F6 user's manual (specifications)
Avoiding it next time
- Use the hood made for each lens.
- Avoid stacking filters on wide-angle lenses.