DavidBM wrote:
I ordered direct from Techart, which - oddly - appears to be the only way you get a guarantee! It’s shipped and arrives in the next couple of days.
Interesting. I ordered mine from B+H several days ago, still says pre-order. Maybe I should cancel and order from Techart as they are already shipping.
It’s interesting what it works well on and doesn’t.
It’s great on my Zuiko 1.2/55, not so great on my Zuiko 1.2/50 (hats the difference), great on 2/28 but terrible on 2.8/28 - which is sharper than the f2 version.
why is that and what do you think is causing this?
DavidBM wrote:
Mine arrived from TechArt
It’s interesting what it works well on and doesn’t.
It’s great on my Zuiko 1.2/55, not so great on my Zuiko 1.2/50 (hats the difference), great on 2/28 but terrible on 2.8/28 - which is sharper than the f2 version.
Aug 29, 2022 at 09:05 AM
Steve Spencer Offline • • • • • • • Upload & Sell: On
It’s interesting what it works well on and doesn’t.
It’s great on my Zuiko 1.2/55, not so great on my Zuiko 1.2/50 (hats the difference), great on 2/28 but terrible on 2.8/28 - which is sharper than the f2 version.
Well that is baffling. I can't think of any reason for different performance from such similar lenses.
Fred Miranda wrote:
Hi David,
Did you upgrade to the latest version? They keep tweaking it.
Yep!
Gotta say I’m pretty happy with it. It works just fine in the central box of a ROT grid on every lens I’ve tried, and variability in the outer field is to be expected. I’m more surprised how good it is in the outer field on some lenses, than disappointed that it doesn’t work so well there on others!
Gotta say I’m pretty happy with it. It works just fine in the central box of a ROT grid on every lens I’ve tried, and variability in the outer field is to be expected. I’m more surprised how good it is in the outer field on some lenses, than disappointed that it doesn’t work so well there on others!
My guess is that the lens with lower performance has a mid-field dip wide open?
Fred Miranda wrote:
My guess is that the lens with lower performance has a mid-field dip wide open?
By my experience it has nothing to do with that.
I tried it with very high resolving lenses and it doesn't work at all outside the central area whereas it "magically" works with actually pretty bad lenses (resolution/contrast wise) right into the corners.
My guess is still that the AF algorithm needs information on the lateral CA of the lens to make proper use of the phase detect pixels.
I don't have enough (or any) knowledge about the AF algorithms and if lateral CA correction is already applied before the focus operation though, which would be a clear indicator of my theory.
BastianK wrote:
By my experience it has nothing to do with that.
I tried it with very high resolving lenses and it doesn't work at all outside the central area whereas it "magically" works with actually pretty bad lenses (resolution/contrast wise) right into the corners.
My guess is still that the AF algorithm needs information on the lateral CA of the lens to make proper use of the phase detect pixels.
I don't have enough (or any) knowledge about the AF algorithms and if lateral CA correction is already applied before the focus operation though, which would be a clear indicator of my theory.
I've asked Techart about this. Let's see what they say.
Fred Miranda wrote:
I've asked Techart about this. Let's see what they say.
I even sent them videos of the good working and (similar) not well working lenses.
Conclusion: they don't have a clue why some lenses work well and others don't.
BastianK wrote:
I even sent them videos of the good working and (similar) not well working lenses.
Conclusion: they don't have a clue why some lenses work well and others don't.
Fred Miranda wrote:
I've asked Techart about this. Let's see what they say.
I'm still waiting for my adapter (ordered on the 10th). A question: Those lenses that work or don't work in the corners, is there any difference between focusing them on "dead" objects or on people with the Face Detect/Eye-AF? If I remember correctly, the Face Detect/Eye-AF uses the CDAF more, than the PDAF, that is why I ask. Thanks!
lattesweden wrote:
I'm still waiting for my adapter (ordered on the 10th). A question: Those lenses that work or don't work in the corners, is there any difference between focusing them on "dead" objects or on people with the Face Detect/Eye-AF? If I remember correctly, the Face Detect/Eye-AF uses the CDAF more, than the PDAF, that is why I ask. Thanks!
I saw absolutely zero difference. Either it works or it doesn't.
bemei wrote:
Does stopping down the 'problem' lenses cure the problem?
Not to the slightest, no. Either it works in the corners or it doesn't.
At least for the ~15 lenses I tried so far.
