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

Started Jun 15, 2014 | Discussions thread
TransientEye Forum Member • Posts: 70
Re: Crop Factor, Low Light and Aperture with m4/3 lenses?

As others have pointed out, you need to scale the focal length and aperture by the crop factor in other to maintain the same field-of-view and depth of field. The main limitation of u4/3 lenses is the small number of really really fast lenses - the best options being the new 42.5mm f1.2 or the excellent Voigtlander manual focus lenses.

Something else that is usually ignored is that the ISO noise also increases with the square of the crop factor. So notionally, a 16MP full-frame at ISO 800 has the same image noise as a 16MP u4/3 camera at ISO200 (assuming similar sensor tech - true if you are used to Nikon, less true if you are used to Canon...).

If you are interested as to why, I have a blog post (with diagrams...)  that tries to show how equivalence works.

Of course, real cameras have many more attributes that may matter more (like ergonomics, or Olympus' excellent image stabilisation).

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Mark

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