Yes, a lot of high end lenses suffer from this too; you don't see it
with jpegs, because they have software correction applied in-camera, and
if you process RAW ouput with a mainstream RAW processor, then it's not
a problem either. I have a Panasonic Leica four thirds Summilux 25
which has quite bad distortion unless you correct for it. We should
try to push to get dt users generating their own LensFun data
Is there any software that will take a jpeg and a RAW of the same image
(one with lots of straight lines, presumably) and work out LensFun data?
Graham
On 27/03/17 13:47, Lorenzo Bolzani wrote:
2017-03-27 11:19 GMT+02:00 Alex Delaforce <123.adelafo...@gmail.com
<mailto:123.adelafo...@gmail.com>>:
The image problem is more than distortion. The image circle doesn't
cover the sensor leaving black corners. If I use jpeg instead of RAW
I think the processor stretches the image to cover the rectangle
corners. Which I think is a bit bodgy!
I'm pretty sure I'm going to send the camera back. But I will try
the xml file sent via this list first.
Cheers
As said, this may be perfectly normal behaviour and you'll find the same
situation on any other comparable camera. To make the lenses so small
and so bright they have to make huge compromises and the first things to
go are the ones that can be corrected in post (distortion, CA,
vignetting). This is true, to a lesser degree, for many high-end lenses too.
An unprocessed RAW file in general is much worse than the default Jpeg.
If the jpeg is fine and the RAW is "bad" it's probably just distortion
correction. Usually this problems vary with focal length.
The image is not stretched, probably it is "corrected" and then cropped.
This is an example:
https://i.stack.imgur.com/1Zzxk.jpg
the original RAW image was bent inward so the correction pulled the
center forward. This bends the borders too so now you have to crop the
picture to make it squared again. The cropping may hide the black corners.
If you want to share a sample RAW file we may better understand the
situation.
Bye
Lorenzo
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Graham White
Electronic Engineering and Computer Science
Queen Mary, University of London
http://www.eecs.qmul.ac.uk/~graham
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