Yohan Pamudji wrote in post #14474541
Slow AF is its only downside for me.
Gotta disagree. If a 17-18mm f/1.7 with the same size and quality were available I would own it instead. I prefer the 35mm angle of view, so cropping the 20mm (40mm equivalent) gets me further
from ideal instead of closer. The 20mm is a fantastic lens, but for those who prefer a wider angle of view it's a stopgap measure until hopefully Olympus get around to updating the 17mm f/2.8 or making a larger aperture version with better image quality as well.
Let me put my point another way, as I think I came off a little strong before....
Basis (arguably all factual):
1.) There is a reason why the term "Normal lens" exists, and it is a psychological reason. For many people a photo shot at or around "normal" for the given format and then viewed at typical viewing distance just feels more "natural". It is a subtle effect, much like the rule of thirds or the golden mean often is, and like those rules it is also meant to be broken. But also like those rules it does work, and works well, to make photos just seem to be "right".
2.) 50mm lenses are called "normal" on 35mm, but they are not. Normal is defined as the focal length equivalent to the diagonal size of the sensor, or about 43mm in the case of 35mm. Shooting slightly wider than this works better than shooting slightly narrower, as you can crop, but not anti-crop, so 40mm on 35mm or 20mm on MFT is a good choice for getting "normal" results from a camera.
3.) Long ago, despite all other formats making and using "normal" lenses that were actually very very close to true normal, 35mm format lens manufacturers decided to go ahead and call 50mm "normal" and make tons of 50mm lenses and almost no 40-45mm lenses. The reason for this was likely that a 50mm is 1x magnification and (relatively) simple to make, as well as it being vaguely close to "normal". Once this became the standard there was little point to making a true normal lens because it was too close to the 50mm lenses everyone already had. So the next logical step down in prime lenses was 35mm. So 35mm lenses became very popular as the closest lens to Normal while 40mm-43mm lenses virtually don't exist.
So with all that as my basis, my belief is that it has now become a psychological effect for many photographers to see 35mm shots and have them just feel "right".... But in reality if we all had been using 40mm lenses all along those would feel "right" now instead. I can't prove this, and it is never going to change to where people as a whole do prefer 40mm on DSLRs, so it is kind of irrelevant, but I still think it is the case.
I think that if you give the 20 f/1.7 a chance, that for the above reasons, it will grow on you very quickly and you won't miss those other 2.5mm at all. Especially if you don't also use a 35mm lens on your DSLR at the same time..... But I did word that part a bit to strongly on my last post. I can't be certain you will, I just think you will for the above reasons.