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

Started Feb 6, 2014 | Discussions thread
viking79 Forum Pro • Posts: 14,151
Re: Here is a real comparison

viking79 wrote:

12-35/40 mm f/2.8 is 12-35/40 mm with 4.3 to 12.5-14.3 mm entrance pupil and 24-70mm f/4 is 6 to 17.5 mm entrance pupil.

In terms of aperture stop area the 12-35/40 is 57 mm^2 to 490-641 mm^2, and the 24-70mm f/4 is from 114 mm^2 to 962 mm^2.

No one bothered to check my math.  I calculated the areas wrong, using the diameter squared instead of the radius squared, so trying that again:

12-40mm is 14 mm^2 to 160 mm^2 and 24-70mm f/4 is 28 to 241 mm^2.  The ratios would be the same which is what my point was, thought 962 mm^2 seemed a bit large


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