johnvanr wrote: Jonas B wrote: johnvanr wrote:
Of course the one thing no one mentions is the price difference.
The OP is shooting with lenses in the focal length range between 24 and 90mm.
Comparing the Sony 40/2.5 with the eqiuvalent OM System 40/1.4 shows the Sony lens is smaller, faster and cheaper.
Comparing the Sony 35/2.8 wih the Olympus 17/1.7 (eq. approx. 35/3.4) shows the Sony lens is smaller, clearly faster and somewhat more expensive.
I'm no longer that familiar with the micro 4/3 system but i think there are zoom lenses in the range that are smaller and cheaper han he FF equivalents (but not really equivalents as there are no that slow FF lenses).
On the 40mm, the Sony isn’t faster. The OM System one is faster. Also, the OM System lens has full weather sealing. Not sure about the Sony one, B&H listing doesn’t mention it.
The 35mm isn’t faster either, they’re close in size with the OM being a bit lighter. And again, the OM has full weather sealing while the Sony is dust and splash proof.
On speed, the aperture remains no matter the sensor size the same thus the MFT lenses are faster. It’s the depth of field that doubles.
I’ve played this game before, including to find a FF system that would work for me like MFT works for me. Only when you run apples to apples comparisons will you get the real picture. Otherwise there are always trade offs.
On the 40mm it depends what you mean by faster. Do you mean a wider aperture or a smaller f number? The Oly obviously has a smaller f number, the aperture of the size of the opening at the entrance pupil is actually bigger on the Sony lens. The difference is small, however. The formula for f number is focal length divided by diameter of the lens opening at the entrance pupil. So we can solve for the diameter at the entrance pupil for the Sony as 40 divided by 2.5 which equals 16mm. We can solve for size of the entrance pupil for the Olympus OM 20 f/1.4 in the same way by dividing 20 by 1.4 and we get 14.29mm, so if we think of the size of the actual hole created by the lens at the entrance pupil as the aperture, which is a useful way to think about aperture, then the Sony lens has a wider aperture by just a little--16mm vs. 14.29mm.
Aug 03, 2025 at 09:42 PM
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