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galenapass wrote
I like to understand the strengths and weaknesses of the tools that I am using.
+1
Whenever I get a new lens ... particularly the alts ... I "torture test" my glass.
MFD wide open is not where many shots are ever taken, but it can reveal things.
Shooting directly / obliquely into the light to check its flare handling.
Of course a series of test shots stepping through @ f-stop intervals will reveal where your diffraction starts to kick in and where it becomes objectionable. Case in point, my 24L TS-E (not alt to some, just stuck in my memory) testing revealed that f/11 in soft light is where it starts to barely show up @ pixel peeping. f/13 it is showing up in slight lowering of contrast ... f/16 and beyond I really don't want to go there unless for some odd reason it is paramount.
Same can be said for essentially any / all attributes of concern.
If I know that my torture testing ... whatever I may concoct / conduct ... that I won't use shows me the "limits" of the lens, then that all else will be better than that.
On the other side of things from finding my "limits" is finding my "sweet spot". In the cast of my 24L TS-E, I know that WO is just a touch softer than if I stop down from WO @ 3.5 to 5.6 or 8. 5.6 is probably the "sweet spot" because there is no real gain in sharpness doing from 5.6 to 8 ( a bit more dof of course), particularly if using a tilt function ... AND ... 5.6 is one stop FARTHER (vs. f/8) away from f/11 where my diffraction starts to reveal.
So, my sweet spot is sandwiched between sharpness and diffraction. Rinse & repeat for other glass. Some are already sharp @ WO and really don't need much stopping down (i.e. the advice of 2 stops from WO). Kinda depends on how the mfr designed the lens. Subject distance can make a diff also. Portrait lenses and macro lenses can be optimized for diff subject distances. Some glass makes better infinity distance, others make better street distance.
With so many attributes in play, testing is a good thing for those who are attentive to it. Some folks, just grab glass and go with whatever is, is. Nothing wrong there either, but if you are inclined to want to know ... I can relate. I'll shoot with anything and nothing will really prevent me from using any camera / glass, but it is nice to know how they differ, so you can work to their strengths ... or sometimes exploit their weaknesses.
Granted, the "pixel peeping" doesn't make a lens good / bad ... but, imo ... learning where it's strengths and limits are, affords one a confidence in their chosen tools.
As to the Oly's ... they tend to have very even sharpness across the frame, where Nikon's or others have a stronger central sharpness in Zone A at the expense of Zone C. For Oly's their issue of concern can be the vignetting that accompanies them, regarding how far you might want to stop down.
On a crop body, though the advice needed for stopping down on FF will be different as you are only capturing a more centralized portion of the image circle projection. I shoot my Oly's on FF, so I chose them for their even sharpness across the frame. Some Voigts and Nikons can tend to have sharper centers (optical compromises). If I were shooting crop, I may not be as interested in the Oly's for their overall more even frame sharpness.
The nuance of alts is a study unto itself. Optics are almost always some form of a trade-off / compromise. Diff mfr's approach those differently. So, depending on one's taste / needs ... there is a bevy of different glass to choose from ... which is not necessarily the same thing as one lens being better than another (unless you qualify "better" @ what).
HTH
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