Originally posted by dgrPhotos In regards to 1 & 2, because the bigger sensor in the Nikon can utilize more of the light coming in and has bigger photosites makes it "cleaner" at higher iso values. #3 becomes moot because of #1 and #2. That's doesn't make it a myth, that's just physics.
A bigger sensor can only utilise "
more of the light coming in", if there is more light to utilise. In other words, it is the lens providing more light to utilise that should be given the credit, not the larger sensor.
If you simply use a larger sensor, but not a faster lens, then the same total amount of light is used; it is just spread out over a larger area with a corresponding loss of light flux (photons per square mm). Projecting the same image onto a larger area and then capturing it with a larger sensor does not give you any noise advantage whatsoever. The noise advantage comes from projecting onto a larger area while maintaining the same flux which means you are using a higher amount of total light. The latter is available only if the lens can provide it.
Ergo, what the lens delivers counts, not what the size of the image forming area is.
Originally posted by jsherman999 There is no larger-sensor advantage if you always must keep DOF the same for the same FOV. But no-one ever mandates that, and in fact 'accepting less DOF for the same FOV' often turns into 'welcoming less DOF for the same FOV' in a lot of cases, once you shoot for a while.
Of course you can change the DOF.
But if you "
accept less DOF" then it is no wonder that noise performance will be better as more total light will be used. This obviously happens if you don't change the sensor size at all. Open up the aperture and you get a brighter (less noisy) image, on FF, APS-C, any format.
You don't need to switch to FF to "
accept less DOF". Just open up the aperture a bit more.
With one exception: If you would like to open up the aperture some more but there is no APS-C lens that allows you to. Then you may want to switch to FF because there are FF
lenses that open up their apertures some more.
The Sigma 18-35/1.8 is an example for a lens that suddenly addressed a low-light shortcoming of APS-C with respect to zoom lenses. Prior to its introduction you could not take certain images with a zoom on APS-C. You had to switch to FF to get these images (because there are respective, faster, FF zooms). Now you don't have to switch anymore (but your sensor size did not need to change for this to happen).
Originally posted by jsherman999 So... 'myth' is misleading...
I disagree.
To claim that a larger image forming area is responsible for a reduction of noise is factually wrong.
I absolutely do not object to someone stating "
I bought an FF camera so that I can utilise the fast lenses that are only available for the FF format (as in they have no equivalent in APS-C mount)
to support my low-light photography".
But people often state (or imply) "
I bought an FF camera because the larger sensor gives me better low-light performance ".
The latter is a "
a widely held but false belief or idea", i.e. a "
myth".
Last edited by Class A; 04-05-2014 at 08:56 AM.