Crop Factor, Low Light and Aperture with m4/3 lenses? Part 2

Started Jun 16, 2014 | Discussions thread
Just another Canon shooter
Just another Canon shooter Veteran Member • Posts: 4,691
Re: Crop Factor, Low Light and Aperture with m4/3 lenses? Part 2

Anders W wrote:

Just another Canon shooter wrote:

Anders W wrote:

"What is known based on the laws of optics is that if we take a lens design for a certain format, say a 50/1.8 for FF, and scale it down in all relevant dimensions so as to make 25/1.8 for MFT, the two lenses will deliver the same resolution if we measure per image diagonal (and the MFT lens twice as much as the FF lens if we measure per mm) at the same f-stop as long as resolution is limited by lens aberrations only."

There is no such thing as limited by lens aberrations only.

In optical theory there is.

No, there is not. You cited a formula yesterday that you do not understand, that proves you wrong.

Diffraction is always a factor.

Of negligible importance at wide apertures.

On 80mp and m43? Did you just scratch you head again?

When we talk about 80mp sensors, it becomes a significant one even at f/1.8.

No, it doesn't.

I take your word for that. Wait, I can actually compute the diameter of the Airy disk (well, I am too lazy for that, so I trusted Cambridge-in-color on that). It is 2.4 microns. An 80mp m43 sensor would have a pixel pitch of about 1.6 microns. Oops!

And you know that 16mp is enough to tell the difference - how? You just scratched your head?

I know it because the lenses on sale today perform noticeably differently on 16 MP sensors.

And you extrapolate that to MF lens on a hypothetical 16mp MF sensor, and then to m43 lens to a hypothetical 80mp m43 sensor?

Am I right to assume that your most serious science effort was to post here?

 Just another Canon shooter's gear list:Just another Canon shooter's gear list
Canon EOS 5D Mark II Canon EF 15mm f/2.8 Fisheye Canon EF 35mm F1.4L USM Canon EF 50mm f/1.2L USM Canon EF 135mm F2L USM +4 more
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