Strange Exposure/Vignetting with new EPL3 and 20mm 1.7

Started Oct 9, 2011 | Discussions thread
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Junior MemberPosts: 29
Strange Exposure/Vignetting with new EPL3 and 20mm 1.7
Oct 9, 2011

Hi, I'm having some unexpected results with a new
EPL3 with 20mm 1.7, and wondering if anyone
has any ideas on what's going on.

In bright daylight and large aperatures (say
between F1.7 and F2.5) I get significant
under-exposure, and also a vignetting pattern
where the bottom third or so of the image is
less exposured than the top. (As opposed
to the usual vignetting pattern where
corners can be darker at large aperatures.)

Here are 2 example shots (resized JPG from camera)
1st: P mode F5.0 1/640s ISO 200
2nd: A mode F1.7 1/4000s ISO 200

I've played with the shadow adjustment
ON/OFF - and it had no effect on this.
The raw files show the exact same behavior.
I've tried all the different metering modes
and get the same problem.

Interestingly, I only get this problem
in bright daylight. Indoors, I can
use F1.7 with what I'd call normal
vignetting (slightly darker corners).

I've also enclosed some test shots of the same
part of blue sky. These were
taken with S priority, and should be roughly
equivalent exposure, but as you
can see the resulting exposure is not
equivalent at all. In order:
F2.8 1/1000s ISO 200 20mm
F1.8 1/2500s ISO 200 20mm

Appreciate any thoughts on this.


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