I am not sure I buy that logic. If so, then the really small digicam sensors would have a correspondingly greater noise advantage over DSLRs.
And I have seen the images from 4/3rd cameras (Oly) and there is no way they have a 1-stop sensitivity in noise compared to APS-C sensors from Canon and Nikon.
Vandit,
I agree that small sensors have no *noise* advantage over DSLRs, but in afocal coupling they do have *aperture* advantage, which is precisely why small digicams work as well as they do - even at low ISOs.
Let us take - as an example - a Swarovski ATS80HD with 30x eyepiece and put different cameras behind it:
1) Nikon P5100 compact
- zoom at widest 7.5mm f2.7 the physical aperture is very close to the exit pupil of the scope meaning that the "digiscope" works at 225mm f2.8 and the crop factor taken into account => 1052mm
f2.8(!)
- zoom at 17mm => "true" 510mm f5.7 => film-eq: 2385mm
f5.7
2) Panasonic/Olympus 4/3
- 20mm f1.7 prime: 600mm f7.5, 2x crop: 1200mm
f7.5
- 25mm f2.8 prime: 750mm f8.9, 2x crop: 1500mm
f8.9
- they could make eg. a 40mm f2.8: 1200mm f15: 2400mm
f15
3) Canon 450D
- 28mm f2.8: 840mm f10.5, 1.6x crop: 1344mm
f10.5
- 35mm f2.8: 1050mm f13.1, 1.6x crop: 1680mm
f13.1
- 50mm f1.8: 1500mm f18.8, 1.6x crop: 2400mm
f18.8
Canon DSLR sensors may very well have that one stop lower high-ISO noise than the 4/3, but my point was that since the 4/3 is about one aperture stop "faster" than the 1.6x-crop DSLR (and P&Ss 3-4 stops faster) it can be used at lower ISOs and actually may not suffer from worse noise. I hope my calculations are correct enough
and that this has made my logic a little more understandable.
Best regards,
Ilkka :t: