8.4Lens Cast
What is Lens Cast?
Lens cast may occur if using the camera back with wide- angle lenses e.g. Horseman Digiflex II, Hasselblad Flexbody or Hasselblad 905SWC or on other large format cameras with different tilt or swing settings. On a medium format camera lens cast is very rare if using fixed lenses from 60 mm to 120 mm.
Why does lens cast occur?
Lens cast occurs as a result of the angle at which the CCD is exposed to light. If the CCD is exposed to light coming from a very sharp angle e.g.
What does it look like?
Depending on the light conditions and photographic setup, lens cast can appear differently, on some lens/back combinations there will appear to be a transition from
-all colors can appear, if you want to test your lens for color cast, take a photo of a grey wall or cardboard. And check this image for colors.
How to get rid of Lens Cast?
If working with large format cameras with tilt and swing, you would have to make a new calibration file if you change the tilt and swing position. Phase One provides a solution in the Capture one software that helps you get rid of the lens cast.
We call it: Lens Cast Calibration (LCC). By holding an opal white plate in front of the lens and capturing a calibration image that you then apply to all of your capture files you are able to remove the lens cast.
On medium format cameras the calibration is very simple: You do one calibration for each lens and then save the calibration files and apply them when needed by clicking “Set as default for new Captures”.
89