Someone on my FB friends’ list just posted an article about a very large camera lens. The photo with the article looked like the lens hood had notches/extensions 8 inches long. What is the purpose of such long extensions on camera lenses?
You need the lens hood to block all light except what will intentionally fall on the sensor/film inside the camera. So the shape of the lens hood is essentially a projection through the lens of the rectangular image inside the camera. The notches are the four corners of that projection of the rectangle.
This picture illustrates it:
Perfect explanation, folks! Thank you so much!
Lens hoods have an added benefit of protecting the lens from damage when it’s bumped against an immovable object.
mmm