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

Started 4 months ago | Discussions thread
knickerhawk
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Re: Crop Factor, Low Light and Aperture with m4/3 lenses? Part 2
In reply to Truthiness, 4 months ago

Truthiness wrote:

Although we don't have any perfect physical speedboosters, we have some pretty good ones, and I think it's clear that the difference in resolution between two 20cm X 30cm prints generated with the same FF lens on an FF camera and on an m43 camera (with a sensor having the same resolution as the FF camera) using a good speedbooster will be much smaller than the difference suggested by the 69 and 267 times required enlargement factors you mentioned, or do you disagree?

You're right for most cases of course - I never claimed anything else.

However the problem is that this thought experiment has no relevancy for this issue: when you use the booster you downsize the image from 43mm diagonal to 21.6mm, thus you use the original lens as intended, all of it's lens area including all of the original image circle. The situation is quite different when you only use the center part of the image circle and enlarge that.

So, in other words, all we need to do is design all m4/3 lenses with FF image circles and speedboosters built in and your "inherent" advantage for FF magnification disappears. Hmmmm...

Since magnification is the root of an inherent and unavoidable evil according to your original posting in the other thread, what do you make of the greater magnification required to project the larger image circle onto a FF sensor compared to the lesser magnification required to project an image circle on a m4/3 sensor? Seems to me that the FF sensor is "inherently" disadvantaged due to the "stress" of having a larger image circle.  Hmmmm...

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