Crop factor and f/stop

[Daniel Browning]

Yes, you need to multiply the f-stop by the FOVCF as well. The reason for this is to achieve the same framing with a 35mm format camera (given the same focal length) you would need to get considerably closer to your subject.

Mark's right. I would add that moving closer or further away will change a vital element of composition: perspective. Many times it's not desirable to change this element of composition, and sometimes it's even impossible. The only way to keep perspective the same between two sensor sizes is to change the focal length by the crop factor.


If any two lenses have the same iris diameter, the DoF, diffraction, and light gathering power will be the same, no matter what the focal length, f-number, or sensor size. Given the same field of view, and non-macro focus distance.

[powers_brent]

ahhhhhhhhhh ok! Now I get it. Perfect. Thanks Guys.