Crop Factor, Low Light and Aperture with m4/3 lenses?

Started Jun 15, 2014 | Discussions thread
Ontario Gone
Ontario Gone Veteran Member • Posts: 4,183
Re: Very simple:

Anders W wrote:

Ontario Gone wrote:

Great Bustard wrote:

50mm f/2.8 on FF is equivalent to ~30mm f/1.8 on APS-C which is equivalent to 25mm f/1.4 on mFT. By "equivalent to" I mean:

  • The same diagonal angle of view.
  • The same DOF for a given perspective (subject-camera distance) and same diffraction.
  • The same total amount of light falling on the sensor for a given shutter speed.

Any differences in noise will be due to differences in sensor efficiency (as opposed to differences in the ISO setting that is used to get the same brightness for a given shutter speed).

Keep in mind that the lower noise of larger formats (since, for a given exposure, as opposed to same DOF and shutter speed, more light falls on the larger sensor) necessarily results in a more shallow DOF, for better or worse. So, unless low noise matters more to you than a deeper DOF, mFT will be a better choice than larger formats for handheld photography in low light.

Very well layed out. I would also like to add, no larger format has stabilization like Oly 5 axis, meaning at the times when subject motion (in low light) is slow enough to reduce SS, those larger sensors lose that noise advantage that is tied to their thinner DOF (and perhaps then some). This IBIS advantage can't be factored all the time as subjects may be moving, but sometimes is better than never.

In all fairness, larger formats offer IBIS too. Sony has it in FF (A-mount) and Pentax as well as Sony (A-mount) in APS-C.

Oh i know, i was just saying that even their OIS/IBIS isn't as good as the Oly 5 axis. I've used SLT IBIS and Pentax as well, it helps but it's in a different league. If subjects are slow enough, IBIS can allow lower ISO, which effectively lowers noise.

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"Run to the light, Carol Anne. Run as fast as you can!"

 Ontario Gone's gear list:Ontario Gone's gear list
Nikon D7000 Canon EOS 70D Nikon AF-S DX Nikkor 35mm F1.8G Nikon AF-S Nikkor 50mm f/1.8G Canon EF 40mm f/2.8 STM
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