How does the f-number of camera lenses affect image area?

  • Thread starter Thread starter Gear300
  • Start date Start date
  • Tags Tags
    Camera Lenses
AI Thread Summary
The discussion centers on the relationship between the f-number of camera lenses and image area. It clarifies that the area of the image is proportional to the square of the image distance (q²), which contrasts with the initial assumption that it is proportional to q. Participants note that while the f-number affects image brightness, it does not influence the field of view. The distinction between image area and brightness in relation to the f-number is emphasized. Understanding these relationships is crucial for photographers when considering lens selection and image composition.
Gear300
Messages
1,209
Reaction score
9
I was reading on the f-number of lenses for cameras...somewhere in the text, they stated that the area of the image is proportional to q2, in which q is image distance. I figured the area to be proportional to q, but I don't really see it as q2...so how does this work out?
 
Science news on Phys.org
The f/# doesn't affect the field of view, so I'm not sure what you mean, exactly. The image *brightness* goes as the square of the f/#, but that's different.
 
I would like to use a pentaprism with some amount of magnification. The pentaprism will be used to reflect a real image at 90 degrees angle but I also want the reflected image to appear larger. The distance between the prism and the real image is about 70cm. The pentaprism has two reflecting sides (surfaces) with mirrored coating and two refracting sides. I understand that one of the four sides needs to be curved (spherical curvature) to achieve the magnification effect. But which of the...
Back
Top