06-14-2016, 06:05 PM
Film speed and sensor speed are not the same - but there's a standard for them: https://en.wikipedia.org/wiki/Film_speed see The ISO 12232:2006 standard and Measurements and calculations.
Btw., sensor area doesn't play a role in the formulas, if I'm not mistaken.
Now, instead of talking theoretically I wanted to see if I'm wrong. I set up the same ISO, measuring method and aperture. First was 23/1.4 (APS-C) and 35/1.4 (FF)
![[Image: i-K6NzGGk-L.jpg]](https://photos.smugmug.com/photos/i-K6NzGGk/0/L/i-K6NzGGk-L.jpg)
Both 1/200 as shutter speed - where is the equivalence? Should be 1/200 × 1.5 = 1/133
Next with f/8: â…›" on both cameras
![[Image: i-HvHbmpm-L.jpg]](https://photos.smugmug.com/photos/i-HvHbmpm/0/L/i-HvHbmpm-L.jpg)
Next were 35/2 (APS-C) and 50/1.4 (FF), I don't have a 52.5 mm lens
![[Image: i-xwJq9kJ-L.jpg]](https://photos.smugmug.com/photos/i-xwJq9kJ/0/L/i-xwJq9kJ-L.jpg)
1/40 for APS-C × 1.5 = 1/26⅓ for FF - but FF shows 1/50. Equivalence?
You can remain in your thinking model and I will in mine. I just never saw a proof for your reasoning. Maybe with a better lit test scene than mine.
Btw., sensor area doesn't play a role in the formulas, if I'm not mistaken.
Now, instead of talking theoretically I wanted to see if I'm wrong. I set up the same ISO, measuring method and aperture. First was 23/1.4 (APS-C) and 35/1.4 (FF)
Both 1/200 as shutter speed - where is the equivalence? Should be 1/200 × 1.5 = 1/133
Next with f/8: â…›" on both cameras
Next were 35/2 (APS-C) and 50/1.4 (FF), I don't have a 52.5 mm lens
1/40 for APS-C × 1.5 = 1/26⅓ for FF - but FF shows 1/50. Equivalence?
You can remain in your thinking model and I will in mine. I just never saw a proof for your reasoning. Maybe with a better lit test scene than mine.