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Strange output from DNG files, JPG are normal

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Offline Microfunguy

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Re: Strange output from DNG files, JPG are normal
« Reply #20 on: 17 / February / 2012, 12:19:13 »
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Quote from: Pier on 17 / February / 2012, 08:57:00
The link:
http://www.4shared.com/folder/Nk6ILUiN/_online.html

Thanks for that, but before I compare them, the out-of-camera JPG is not full resolution.
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Offline Pier

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Re: Strange output from DNG files, JPG are normal
« Reply #21 on: 17 / February / 2012, 12:22:36 »
@Lebeau

All right.
And the QUESTION is: Why they do not made the sensors bend , all surface to be in touch with the
Focal plane ?  ;)
I'm sure this linear distortion and vignetting absent, or is very small when the subject is not so close to the
Lens.In my case think the foreground was about 50 cm near the Lens.
But FW (or Post Proccesing) do they job and all is OK.
« Last Edit: 17 / February / 2012, 12:34:47 by Pier »
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Offline Lebeau

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Re: Strange output from DNG files, JPG are normal
« Reply #22 on: 18 / February / 2012, 08:26:12 »
The curvature of the lens focal plane depends on focal distance (wide-angle ... tele) :( that is different of the focus distance !

If you find a way to bend the sensor upon the lens focal distance, you are a winner :)

It is not "how far" the focus point is, it's the lens focal point inside the cam, therefore, when you choose wide-angle (5 mm) distortion is fish-eye like, when you choose tele (70 mm), distortion is quasi-null meaning the lens focal plane is near flat, as the sensor is.

Canon DSLR fisheye lens (on dpreview) offers 8 to 15 mm focal and SX230 has 5 mm wide-angle !
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Offline Pier

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Re: Strange output from DNG files, JPG are normal
« Reply #23 on: 18 / February / 2012, 09:26:42 »
@Lebeau
Quote
If you find a way to bend the sensor upon the lens focal distance, you are a winner  :)
Well, maybe some day it may occur - sensor to bend with Lens moving  ;)
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Yes, it's correct for old 35 format (8 mm and 10 mm FL), DSLR FF (15–16 mm FL) and todo realy fish-eye "distortion" on a small P & S Cams we need 1 to 2 mm FL... (wikipedia)
If we know that and our Cam features, all is O'Key - we know what to do.If shooting with 5 mm Focal lenght with my Cam close to the object, I can do something like Fishe-eye effect in post procesing, to do not touch the Lens correction-only Crop and little bit vignetting for the dark corners in the picture.On my SX130IS I notice that only two bottom left/right corners needs a little vignetting.


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Offline Microfunguy

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Re: Strange output from DNG files, JPG are normal
« Reply #24 on: 18 / February / 2012, 10:13:34 »
@Pier

The reason you need the full-resolution JPG before comparing them is because you can then load as layers into the editing programme and flick between each layer.
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Offline Pier

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Re: Strange output from DNG files, JPG are normal
« Reply #25 on: 18 / February / 2012, 13:06:35 »
@Microfunguy,
Thanks for that.
I'm not familiar with these layers as yet.And many other things, but learn and try to understand
post -processing and pictures editing in deep.
« Last Edit: 18 / February / 2012, 13:08:11 by Pier »
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Offline Microfunguy

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Re: Strange output from DNG files, JPG are normal
« Reply #26 on: 18 / February / 2012, 13:32:34 »
By loading the dng and full resolution JPG as layers, you can make the top one semi-transparent and align the middle of that image with the other image.

Set it to non transparent and click the top layer on/off.

Not only will you see the distortion changes, you will see colour, sharpness, noise etc for the same region on both images.
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Offline reyalp

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Re: Strange output from DNG files, JPG are normal
« Reply #27 on: 18 / February / 2012, 14:12:18 »
Quote from: lordhades on 15 / February / 2012, 14:02:46
This is how it looks like guys. Someone help!
As Microfunguy said, that looks like an incorrect cfa pattern. If you tell me which Canon firmware version of A3300 you have, I can make you a test build with the other pattern.
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Offline stalker78

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Re: Strange output from DNG files, JPG are normal
« Reply #28 on: 18 / February / 2012, 14:30:01 »
Quote from: Microfunguy on 16 / February / 2012, 14:22:18
It is unfortunate that so many people request a CHDK port for their camera simply, or mainly, for so-called raw support.

They seem to think they are getting DSLR quality for free.

I'm not such person. As I said I use Nikon DSLR also. I'm using CHDK just for curiosity and experimenting, not for "free RAW support". I'm realist and I'm not expecting DSLR quality in small P&S camera, really. I bought my SX230HS because of its quality, dimensions and ease of use (in such order). DSLRs are pain sometimes...

PS. Lebeau answered my question perfectly. Thanks!
« Last Edit: 18 / February / 2012, 14:37:18 by stalker78 »
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Offline stalker78

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Re: Strange output from DNG files, JPG are normal
« Reply #29 on: 18 / February / 2012, 14:35:20 »
Quote from: Lebeau on 17 / February / 2012, 10:10:19
Any lens produce a circle of luminosity (cylindric symmetry). That circle has a focal plane that is not flat. (...)

Thanks, man. That's an answer I'm really pleased of. Substantial and full of physics/mathematics/geometry.

I'm not kidding. I really like it.
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