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Why does Autopano darken my photos?

PostPosted: Sun Mar 31, 2013 5:50 pm
by Photonicwand
Hi there,

I am struggling getting the output from autopano that I am looking for. Specifically, the panoramas usually come out too dark. I believe I must be missing a trick.

Before I use autopano, I convert my photos from raw into 16-bit tiff files using a tool called darktable. I then use those 16-bit tiff files in autopano to generate the panorama. As I shoot my photos fully manual and adjust lighting and color in darktable, I would like autopano not to leave the color and brightness as much as possible as it is in the 16-bit tiff input pictures.Even when f I set the "color correction" to non and do not tocuh the levels, autopano still darkens the output. When I lighten the panorama using the levels tool, the result seems "washed out" compared to the original.

Is there any way to avoid autopano changing the lighting apart from what it needs to do to blend the images together?

Thanks for any tips!

Johan

PostPosted: Sun Mar 31, 2013 5:56 pm
by DrSlony
Screenshots would help understand how much of a difference youre talking about. "Do not touch the levels" but AP sets them automatically, try resetting them.

PostPosted: Sun Mar 31, 2013 6:21 pm
by klausesser
Photonicwand wrote:Hi there,

I am struggling getting the output from autopano that I am looking for. Specifically, the panoramas usually come out too dark. I believe I must be missing a trick.

Before I use autopano, I convert my photos from raw into 16-bit tiff files using a tool called darktable. I then use those 16-bit tiff files in autopano to generate the panorama. As I shoot my photos fully manual and adjust lighting and color in darktable, I would like autopano not to leave the color and brightness as much as possible as it is in the 16-bit tiff input pictures.Even when f I set the "color correction" to non and do not tocuh the levels, autopano still darkens the output. When I lighten the panorama using the levels tool, the result seems "washed out" compared to the original.

Is there any way to avoid autopano changing the lighting apart from what it needs to do to blend the images together?

Thanks for any tips!

Johan

Hi!

Does darktable include a profile?

best, Klaus

PostPosted: Sun Mar 31, 2013 8:27 pm
by Photonicwand
DrSloney - I will try to upload some screenshots although it may be hard to show the difference without uploading the original files. What do you mean by "try to reset them"?

Klaus, darktable does deal with profiles - I use the profile my calibrated monitor profile for displaying the photos and export it in sRGB format. I do not believe that autopano can manage profiles, can it?

PostPosted: Tue Apr 02, 2013 5:35 am
by Photonicwand
As promised, please find below a s screenshot comparing similar sections of the resulting panorama (on the left) with one of the original photos (on the right). The difference is most visible on the tree bark and the entrance door to the church. Note that the original panorama was taken slanted and therefore the photos are not completely in the same direction.

Both photos are 16-bit tiff files shown with the same image viewer.

PostPosted: Tue Apr 02, 2013 9:28 am
by lumelix
Hi
There is also a "automated color correction" in the "main settings - detection".
Have you unchecked this before importing the images ?

The difference looks like some gamma correction for me.

PostPosted: Tue Apr 02, 2013 4:01 pm
by ThomasV
Hello,

Could you please upload some of the source pictures to the ftp server so that we can give a deeper look at this issue? (http://www.kolor.com/forum/t766-ftp-server)

Regards,
Thomas

PostPosted: Tue Apr 02, 2013 7:37 pm
by Photonicwand
lumelix wrote:There is also a "automated color correction" in the "main settings - detection".
Have you unchecked this before importing the images ?

Thanks for that hint - I just verified this setting and it is unchecked (as are the other "auto" settings)

lumelix wrote:The difference looks like some gamma correction for me.

You may be right, but how do I avoid this from happening?

PostPosted: Tue Apr 02, 2013 7:45 pm
by Photonicwand
ThomasV wrote:Could you please upload some of the source pictures to the ftp server so that we can give a deeper look at this issue? (http://www.kolor.com/forum/t766-ftp-server)

Thanks, Thomas. As I was preparing to upload my images and the .pano file I noticed something interesting: when I re-opened the .pano file after having saved the project last time, the color and brightness is correct and I could render the output correctly. I want to experiment with this a bit more to see if I can reproduce my original results by starting from scratch and whether saving and re-opening the .pano file fixes the problem. If so, autopano still should not behave this way, but it would be a workable workaround.

PostPosted: Wed Apr 03, 2013 12:10 am
by lumelix
Hi Johan

Well!
Have you used different versions of APG for stitching and rendering ?

PostPosted: Wed Apr 03, 2013 7:48 pm
by Photonicwand
Odd - I cannot replicate the problem anymore even when I start the same panorama from scratch. Something I did while I was following your suggestions appears to have cleared or set something that fixed the problem for now.

I will pay attention to future panoramas I work on and see if the problem re-occurs, but for now the problem appears to be solved. The only challenge is, I don't know what changed and why the problem does not occur anymore!

Thank you everyone for your help - I appreciate it.