Calibration upload 7575b4 about lensfun HOT 11 CLOSED

I am the uploader.

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The original uploader has uploaded the very same files again. It should be discussed with the uploader why this was done.

from lensfun.

Hi, I'm trying to upload this file:

❯ sha1sum Sigma_24_70_Art_Calibration.tgz
6dd7871c81ca6c466af8caf827fd7129368255e8 Sigma_24_70_Art_Calibration.tgz

If that is not the file I sent you, then I apologize because I indeed sent the incorrect files, and I will need to send you the correct files.

If that is the file I sent you, then it has better photos than the original calibration upload from about a week ago. Particularly it has Vignetting photos.

If I tried to send the exact same file twice (that is, the one with the SHA1 Sum I listed), then that's just user error. The upload takes a very long time for me, and perhaps I clicked the upload button a second time after returning to my computer. And if so, I apologize, I realize that you all have limited disk space and time.

from lensfun.

This is the original calibration upload that was already processed
#2195
The sha1sum for those photos is this:
❯ sha1sum Sigma_24_70.tar.gz
b29fe6f8cef9dc75173f673096088b25f09508f6 Sigma_24_70.tar.gz

I'm hoping that you can use the Vignetting and the TCA photos from this upload.
That is:
❯ sha1sum Sigma_24_70_Art_Calibration.tgz
6dd7871c81ca6c466af8caf827fd7129368255e8 Sigma_24_70_Art_Calibration.tgz

I also think that my Distortion photos are better in this upload, I was very careful with the ISO and focus, and used a different location that seems to have better lines.

A long time ago, I also submitted these other photos, but they weren't good enough for processing:
#1975

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@rickprice
... a nightmare in pictures!

Uploaders could make our work a lot easier if they carefully read and follow the information provided here and here and only upload the images that best match the information given. So the uploaders should:

• View all images before uploading and sort out the unusable ones
• limit the number of images to the correct and necessary focal length, aperture and distance sequences
• provide the file names of the images with aperture and focal length
• put the images in folders (distortion, tca and vignetting with any necessary subfolders for the focal distances)

Unfortunately, your pictures for vignetting are not suitable for calibration.
To test it, I created a profile with the pictures taken at focus infinity. When using the profile, there were strong overcorrections at the edges and corners of the image.
For taking the vignetting pictures, it is very important that the image field is illuminated really evenly. Especially when artificially lighting on a ceiling is used, it often happens that the center of the ceiling spot is illuminated a little brighter than the edges of the taken image field. This then leads to over correction of the vignetting and this is especially true for wide-angle shots.

Your vignetting images from #1975 seem much better. I created a profile (see attached file) with them that at least corrects the images available to me well. Unfortunately, I don't have any images with wider apertures (2.8 - 5.6) available for further tests.
It would be helpful if you could upload a few images like this (blue sky or another even, not too white area) in a new upload.

from lensfun.

Okay, I will redo the vignetting photos and be careful to follow the instructions. And will sort them by focal distance.
I will also do it outside with an even sky.
Is there any straightforward way to double check the images before I send them to you? I am able to run the Python scripts that do some of the work for instance, maybe I can check things before I upload them?

from lensfun.

I forgot to attach the profile to my last message. If you want, you can test it with some of your normal shots.
If you have a Linux OS available, the best solution would be to create the profile yourself with the script calibrate.py and make it available via PR. This way you could test everything yourself beforehand.
Sigmar__24-70mm_f--2.8_DG_OS_HSM.zip

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Generated new data from the last upload (see here)

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Thanks for doing that :)

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How do I get you the vignetting photos? I can run the calculations and do a PR, but in the interest of recording the RAWs for posterity, do I just do a new photos upload and reference this issue?

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If you create a PR, we don't need all your vignetting pictures. More important are some "normal" pictures, on which we can test the data.
Generate the vignetting data and test this data on different pictures. Pictures of evenly lit, colored surfaces with little structure (e.g. walls, blue sky, garage doors, etc.) are best suited for this. The photos should have been taken with different focal lengths and apertures. Photos taken with open apertures are particularly important. If you are happy with the results (note: slightly under-correction is more acceptable than over-correction), then create the PR and reference to this issue and the upload of some of the pictures mentioned above (4–5 images with low f-numbers at different focal lengths is enough) with which we can briefly test whether your vignetting profile is correct. If you want, you can also add 2-3 of your vignetting photos.

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