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The distortion issue - A scientific approach and why you (likely) all have it

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By Illux, Senior Member on 17th June 2017, 03:12 AM
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Hey there,

I know, lots of threads out there and many argue they have more or less issues with distortion. Now, I happened to have had a few lectures - or a few more - in Physics (Optics) back in college and I'm still a passionate photographer.

Here is the basics: All lenses have distortion. The light is redirected, that causes distortion. So what do you do? Easy, you create a lense profile that exactly fits the distortion pattern and corrects the incoming information. That is possible if the lens has a regular distortion pattern, e.g. if the cut of the lense is accurate.

How do you check that? Now, you need a little time, a tripod and a checkerboard pattern. You then put the lens you want to test STRAIGHT in front of the pattern and make sure the orientation EXACTLY fits the one of the checkerboard (linear distortion).

You take a picture.

Now you talk half of the picture (like the right side of your picture), mirror it and see if the mirrored part fits the original (ofc the left part in this case).

This is what I did. Here are the results.

1

2

The Sony Xperia XZ Premium distortion issue is a lens issue. The mirrored pattern fits the original pattern exactly, the deviation is zero. Lenses are produced in ridiculously big batches, I doubt that there is even more than one producer. An unclean cut e.g. production waste causes non-linear distortions - but that is not the case here. I'd bet that non of you has distortion different from what I have found, it's about proper testing.

"But I can barely see it on normal pictures" - Yes, because that is how our human brain works. We understand optical patterns as logical and commonly don't see them. What we see is deviations. When tested empirically, 90% of all test participants cannot tell whether or not a picture has common lens distortion (e.g. differs from what you'd see in case u saw it with your own eyes).

So - Sony can handle this by patching an appropriate lense profile.
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17th June 2017, 07:27 AM |#2  
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My issue is the same. I am not a professional photographer but I know that this is a lenss issue. So you think Sony can patch this with software update?
17th June 2017, 09:36 AM |#3  
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Quote:
Originally Posted by tomo100brt

My issue is the same. I am not a professional photographer but I know that this is a lenss issue. So you think Sony can patch this with software update?

It can at least be corrected to a degree where one won't notice it anymore.
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17th June 2017, 02:20 PM |#4  
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So I hope Sony will admit this issue and release a software update? I think they're still not admitting this issue as an issue.
17th June 2017, 02:26 PM |#5  
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They still have a lot to improve with the camera. While it's pretty good imo, the low light quality could be better, the minor distortion could be fixed (even if not completely, better than how it is now), the camera app can be improved a lot with new settings, the quality of 960fps videos can really be improved (I understand it's 720p, but here I am talking about the artifacts it has in anything but perfect light), and they should make Timeshift (that feature where it takes 60 pictures in 1 second) available already (my old Z always had it).
17th June 2017, 03:44 PM |#6  
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Quote:
Originally Posted by chesterr

So I hope Sony will admit this issue and release a software update? I think they're still not admitting this issue as an issue.

yes, sony staff still remain silent on this ,so bad,
Xzs the same problem has been two months, still silent
17th June 2017, 04:49 PM |#7  
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Thanks for the super detailed professional explain here. And I agree with the above guys that Sony does not admit that there is a problem, has remained silent for a long time, that is weird.

and I used your photo to update the Sony Forum posts which they have deleted and restored,hope you don't mind.
https://talk.sonymobile.com/t5/Xperi.../1226731#M1880

photo
18th June 2017, 11:34 PM |#8  
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hi @Illux
any idea for below ?


A little progress here
(I don't know this is progress for camera mode or not,but I think it's helpful to understand ,there really is a serious distortion)

On camera video mode (FHD60fps,FHD 30FPS ,HD),the distortion will disappear only when you switch SteadyShot on. turn it off the distortion will be appear obviously. As we know electronic stabilization need "sacrifice" some pixels to processing stabilization data,This is why switch SteadyShot on will cause the composition different. But I compared the video pixel and clarity between on and off,the difference is not particularly noticeable.So I guess there really have a good one distortion correction parameter for 1080P and 720P Pixels proportion, like a professional camera have for different lens which you can free to switch on and off, even adjust the distortion correction level.
On 4k video mode still have distortion no matter you turn on or off the SteadyShot. I think cause 4K mode using full pixel sampling and then compressed merge pixels,recorded all the distortion just like the camera mode use full pixels.
So is there a good distortion correction parameter for full pixels shooting ?
or already have one but not working like 1080P and 720P?
or the full pixels correction it is already the best we can get ?





And when you video shoot three-dimensional objects turn off SteadyShot move angles around , you will see the distortion make perspective increase serious bad.
Try turn it on , it's much much better just like a normal camera does ,still a little bit of deformation but that is totally in acceptable range.
Try video the person you familiar with , easily move around shoot by different angles and distances,you will not see the SUPER body parts distortion which in the camera mode.
19th June 2017, 12:55 AM |#9  
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Quote:
Originally Posted by feskey

hi @Illux
any idea for below ?


[yadayadayada]

First of all, interesting findings. Didn't occur to me to try that out. Nice idea. It's not only some, it's important progress

Well, I did a very short research on SteadyShot, seems they crop the picture and use the sensor as multi-grid, meaning as long as one part of the sensor captures an equivalent image to the one before, you get a steady video.

That means there is countless(!) sub-lens profiles somewhere that manage to produce corrected images if only a part of the sensor is in use - but not a single one that works for the entire sensor. Wtf.

I'm puzzled.
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21st June 2017, 06:04 PM |#10  
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Quote:
Originally Posted by Illux

First of all, interesting findings. Didn't occur to me to try that out. Nice idea. It's not only some, it's important progress

Well, I did a very short research on SteadyShot, seems they crop the picture and use the sensor as multi-grid, meaning as long as one part of the sensor captures an equivalent image to the one before, you get a steady video.

That means there is countless(!) sub-lens profiles somewhere that manage to produce corrected images if only a part of the sensor is in use - but not a single one that works for the entire sensor. Wtf.

I'm puzzled.

OK ,Now sony developer said this is normal , and decided to respond for fix this issue, I am considering to return refund.
22nd June 2017, 03:59 AM |#11  
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Wow this is interesting. I just ordered this phone.. Starting to regret it now
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