MFT 25mm f/1.4 fails to blur background like Full Frame 50mm lens @ f/2.8

Started Feb 16, 2014 | Discussions thread
Anders W Forum Pro • Posts: 21,468
Re: A different comparison Redux...E-M1 AF glitch (grrrr...)

amtberg wrote:

David Kieltyka wrote:

Anders W wrote:

Sounds weird that you'd have a misbehaving AF point on your E-M1. With DSLR PDAF such a diagnosis makes sense but how could one even hypothetically explain such a thing with mirrorless CDAF?

I'm baffled. But it's repeatable with different lenses and different focus distances. That one point just won't focus properly. Even choosing large vs. small AF point sizes makes no difference. I think I'll give the sensor a cleaning & see if that corrects it.

Many thanks at any rate for redoing the test. While the 25/1.4 at f/1.4 can be expected to be inferior to the 50/2 at f/2.8 for sharpness, its inferiority can hardly be expected to be quite as pronounced as it initially appeared.

I should've caught that before posting. The PanaLeica at f/1.4 is indeed very good, as the redo shows.


Does the E-M1 use a combination of CD/PDAF when native MFT lenses are used? If so that could have something do with it.

Reportedly, it doesn't use PDAF at all with native lenses and AF-S (which I presume is what David used here). PDAF is for FT lenses plus AF-C.

Even with PDAF, it's difficult to understand why a certain AF-point would misbehave when, as here, the PDAF sensors are integrated in the main sensor.

I understand David's idea about sensor cleaning. I admit that seems far-fetched too, but it's at least a hypothesis. I usually have no difficulties coming up with hypotheses about things like these. The problem is usually that there are too many reasonable ones rather than too few. But in this case, I am at a loss, at least this far.

 Anders W's gear list:Anders W's gear list
Panasonic Lumix DMC-G1 Olympus OM-D E-M5 Olympus E-M1 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS Panasonic Lumix G Vario 7-14mm F4 ASPH +28 more
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