Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
new article: Equivalent Focal-Length, Aperture and Speed of Camera Systems
#10
A few notes: 
  • Sensor sizes vary. Especially Nikon sensor sizes can go from close to 1.5x crop factor to 1.56x crop factor, but you state one specific size. No biggie, but could be more accurate.
  • With MFT's 2x crop factor is derived from the diagonal. 17.3mm width and 13mm height give a 21.64mm diagonal. FF has a 36mm width, 24mm height, giving it a 43.67mm diagonal, which gives it a very near 2x (1.9993) crop factor. You could define the crop factor by looking at the horizontal FOV, which would then be 2.08x. Or the vertical FOV: 1.846x. Or you could crop the 4:3 to 3:2, then you end up with the same diagonal FOV and crop factor as the horizontal one: 2.08x.  I am unclear what you derive that 1.92x from? Maybe I made a mistake?
  • FF actually has more like a 1 1/3rd stop advantage over APS-C, to keep things "right". ( 1.6 x f2 = f3,2, 1.5 x f2 = f3. 1 stop would be f2.8)
  • To get a more appropriate APS-C example, use an FF lens Wink. Canon EF 70-200mm f4 L  or Nikkor 70-200mm f4 VR. Yeah, I know that is wonky image circle wise, but truth is that with these longer lenses aperture starts to dominate the optics size (and the wonkiness is to APS-C's disadvantage anyway, so who cares). The weight of the 2 Canon 70-200mm f4 lenses is 705/760 grams.
  


Messages In This Thread
new article: Equivalent Focal-Length, Aperture and Speed of Camera Systems - by Brightcolours - 08-23-2016, 08:12 AM

Forum Jump:


Users browsing this thread:
1 Guest(s)