Focal length 35mm equivalent, but not F-stop?

Started Jul 24, 2014 | Discussions thread
Lee Jay Forum Pro • Posts: 55,137
Re: Whoops!

Tim Tucker wrote:

Are we just talking about noise generation in digital sensors here?

No, we're talking about the noise that's in the light itself (due to the quantum nature of light).  And the signal to noise ratio that such noise generates on its own is equal to the square root of the total number of photons.  More SNR = good, therefore more light = good.  More light comes from either brighter light (faster f-stop) or more capture area (bigger sensor).  Given the same f-stop, a sensor with 16 times more sensor area will capture 16 times as much light and therefore have four times the signal to noise ratio, which is the same as if the small sensor had been using an f-stop four stops faster with the same shutter speed.

IOW, FF 1/60th f/8 = 4x-crop 1/60th f/2, as far as signal to noise ratio goes.

-- hide signature --

Lee Jay

 Lee Jay's gear list:Lee Jay's gear list
Canon IXUS 310 HS Canon PowerShot SX50 HS Canon EOS 7D Mark II Canon EF 70-200mm F2.8L IS II USM Canon EF 8-15mm f/4L Fisheye USM +23 more
Post (hide subjects) Posted by
(unknown member)
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow