Vignetting in bright sky condition on Point-n-Shoot film camera

[lilneige]

I am not really a technical guy but as far as I know, vignetting usually occur in large aperture, and it will improve when step down the aperture.

What I had encountered just puzzles me, it is the opposite of the above theory.

It was extremely bright sky, so I had to step down the aperture to F/11 or F/16 in order to fit in the max shutter speed. This is the setting that I got some image with noticeable vignetting and the first condition that I meet that would produce vignetting on this camera.








On the other hand in a cloudy day, the lightening wasn't as good, therefore required a larger aperture to incorporate the light. Same camera, same film, but no vignetting occurs.



Don't get me wrong, I actually love the vignetting effect on the two photos that I post above. I am just wondering how it occur. Does any one else experienced this on a point-n-shoot film camera?

 

[kzphoto]

What you're seeing happens quite often cameras with leaf-shutters in bright conditions. The inside of the image receives more exposure because the blades swing open and then inward to close, so the center of your image is getting more exposure.

 

[lilneige]

What you're seeing happens quite often cameras with leaf-shutters in bright conditions. The inside of the image receives more exposure because the blades swing open and then inward to close, so the center of your image is getting more exposure.

Thank you for the reply.
After digging the internet, I found my camera has a 7-blade shutter mechanism, and it function like what you described. So I think is must be the answer for my question.