Size comparison of FE 4/2470 on A7 vs Olympus 12-40 f2.8 on GX7

Started 5 months ago | Discussions thread
Krich13
Regular MemberPosts: 381
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Re: Doesn't work like that
In reply to Erik Magnuson, 5 months ago

Erik Magnuson wrote:

Krich13 wrote:

Well, these x0.2 and x0.3 magnification factors are those of the lenses themselves. Sensor size makes a big difference though: Olympus magnification is like x0.6 in FF terms.

Doesn't work like that unless you are also using a 16MP FF sensor.

I prefer to look at the lens magnification with respect to the sensor size (unless it's an empty magnification, but that's another topic). Today Oly sensor is 16 MP, tomorrow it may issue a new sensor of higher pixel count -- but the lens will remain the same.

However, for the purpose of this discussion that is irrelevant. So let's go on with 16 MP m43 sensor vs 24 or 36 MP A7(r)s.

A 2-cm tall bug would fill the frame (height wise) of an m43 camera when used with Oly 12-40 lens,

I think you need to re-check your math: a 20mm bug * 0.3x would be only 6mm long on the sensor and so not cover even 1/2 of the height of an MFT camera. It would cover ~1600 pixels.

You are absolutely right: I made a mistake using factor 2 (the crop ratio) one time too many. Indeed, the bug would be almost half the sensor size in this case, not full size.

but only occupy 1/6 of a frame height if imaged by Sony A7(R) and Zeiss 24-70.]

Even the pixel count of A7R can't compensate the difference in magnification.

No, but it's a lot closer than you make out. To get the bug to cover 1600 pixels on the A7R, you only need a 0.4x magnification lens.

Yes it is closer than I mistakenly presented, but the difference is still huge. You need x0.4 magnification on A7, but this Zeiss only delivers x0.2. That's full two times difference in Linear resolution in favor of Olympus/m43 combo. Four times in aerial/pixel/detail resolution. 6 times advantage over A7 (not R)/Zeiss 24-70.

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