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Interesting ...
#1
The mighty Sony 85mm f/1.4 GM shows ... RSAs.
Chief Editor - opticallimits.com

Doing all things Canon, MFT, Sony and Fuji
#2
Sony focuses with aperture closed, it's not a big problem for them
#3
If you focus wide open and stopped down you get a image OOF.... That means that the focus wide open mostly is a bit different from focussing closed down.
The Sony then will show the opposite: you focus closed down, and then take the image wide open, giving an OOF wide open image.
Or don't Sony FF cameras nowadays close down the aperture somewhat when taking wide open images, like they used to?
#4
Sony keeps same aperture used when focusing and when shooting so RSA isn't an issue, here it makes sense, however when you use f22 and the lens starts hunting to focus even in bright sunlight, you ask yourself what is Sony thinking ?
#5
I'm not totally sure whether this is generally true. Yes, Sony cameras do stopped-down AF.
However, do they really stop down at all costs (e.g. in the dark)? Haven't tested this.
If you have marginal light, you will stick to f/1.4 anyway (unless on a tripod).
As far as f/22 is concerned ... other than for macro, I'm a little wondering why you'd use that regarding the associated softness.
I never had issues with stopped down focusing on the A7R I/II at least.
Chief Editor - opticallimits.com

Doing all things Canon, MFT, Sony and Fuji
#6
It used to be that Sony stops down for AF a few stops with big aperture lenses with mirrorless and the live view DSLTs., even if you shoot wide open and even if your shoot in the dark. Since I have no Sony mirrorless camera I can not check into if they still do that.

As far as I understand, Sony does not focus a f1.4 lens wide open, but "relatively" wide open with Live View Display Setting Effect OFF, so not really wide open, the same as it was in the DSLT days? And not Af really at f1.4 but that rather illustrious "relatively wide open" when shooting at f1.4 with Live View Display Setting Effect OFF. So, when shooting at f1.4, but the lens not being at f1.4 during Af, you can see the reverse issue with a lens with real RSA issues that you'd see with the Canon EF 50mm f1.2 L USM in limited circumstances.
#7
(07-20-2019, 09:58 PM)Klaus Wrote: I'm a little wondering why you'd use that regarding the associated softness.
Sunstar effect, with my 16-50 you need f16 ot f22 to have it, with this setting A6000 starts to hunt for focus.
#8
Shooting stopped down to F16, how much AF really matters? Use of MF based on DOF comes to mind as no fuss workaround. Or single point AF on nearby, more suitable target.

Putting aside that sunstar effect scenario could imply high contrast scene with which most AF systems fail at some point anyway.
#9
(07-21-2019, 08:47 AM)Brightcolours Wrote: It used to be that Sony stops down for AF a few stops with big aperture lenses with mirrorless and the live view DSLTs., even if you shoot wide open and even if your shoot in the dark. Since I have no Sony mirrorless camera I can not check into if they still do that.

As far as I understand, Sony does not focus a f1.4 lens wide open, but "relatively" wide open with Live View Display Setting Effect OFF, so not really wide open, the same as it was in the DSLT days? And not Af really at f1.4 but that rather illustrious "relatively wide open" when shooting at f1.4 with Live View Display Setting Effect OFF. So, when shooting at f1.4, but the lens not being at f1.4 during Af, you can see the reverse issue with a lens with real RSA issues that you'd see with the Canon EF 50mm f1.2 L USM in limited circumstances.

You can clearly see that the DoF changes in the viewfinder when stopping down.
In the bokeh highlight test the discs are at maximum size at f/1.4.
However, I haven't checked all this systematically. So far I haven't seen any negatives as far as Sony's AF accuracy is concerned - thus if the results are good enough, it's good enough for me.

The RSAs may be more relevant for macro but that's out of scope for the Sony 85mm GM. The min focus distance is pretty long.
Chief Editor - opticallimits.com

Doing all things Canon, MFT, Sony and Fuji
#10
(07-22-2019, 11:44 PM)Klaus Wrote:
(07-21-2019, 08:47 AM)Brightcolours Wrote: It used to be that Sony stops down for AF a few stops with big aperture lenses with mirrorless and the live view DSLTs., even if you shoot wide open and even if your shoot in the dark. Since I have no Sony mirrorless camera I can not check into if they still do that.

As far as I understand, Sony does not focus a f1.4 lens wide open, but "relatively" wide open with Live View Display Setting Effect OFF, so not really wide open, the same as it was in the DSLT days? And not Af really at f1.4 but that rather illustrious "relatively wide open" when shooting at f1.4 with Live View Display Setting Effect OFF. So, when shooting at f1.4, but the lens not being at f1.4 during Af, you can see the reverse issue with a lens with real RSA issues that you'd see with the Canon EF 50mm f1.2 L USM in limited circumstances.

You can clearly see that the DoF changes in the viewfinder when stopping down.
In the bokeh highlight test the discs are at maximum size at f/1.4.
However, I haven't checked all this systematically. So far I haven't seen any negatives as far as Sony's AF accuracy is concerned - thus if the results are good enough, it's good enough for me.

The RSAs may be more relevant for macro but that's out of scope for the Sony 85mm GM. The min focus distance is pretty long.

Can you see the aperture closing a bit when focussing when "shooting wide open"?
  


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