LensFun XML guide?

**BigMackCam** · 07-12-2018, 10:02 AM

I've just started producing lens calibration data for some of my lenses using Hugin's Calibrate Lens tool, and I'd now like to patch the relevant XML files locally to include the new lenses. Although I can sort of figure out what's required by looking at the existing XML, I'd like to be sure I'm doing it correctly. I understand that there used to be a manual written by Andrew Zabolotny at http://lensfun.sourceforge.net/manual/database.html, but it seems that's no longer available (I'm getting a 404 error). Does anyone have a copy of the manual, or alternatively, could someone explain to me exactly what's required?

Any help would, as always, be very much appreciated. Thanks in advance

Last edited by BigMackCam; 07-12-2018 at 10:36 AM.

aaacb · 07-12-2018, 01:54 PM - **1 Like**

Is this the XML doc you're looking for? It's linked from the API doc on the lens fun sourceforge page. Just guessing, haven't worked with lensfun before.

lensfun: Database file format

**BigMackCam** · 07-12-2018, 03:13 PM - **1 Like**

Originally posted by aaacb

Is this the XML doc you're looking for? It's linked from the API doc on the lens fun sourceforge page. Just guessing, haven't worked with lensfun before.

lensfun: Database file format

That's a big help - thank you!

I can figure out most of what I need to do from that... the only thing (I think) that I'm missing is how to map and/or calculate a, b, c values in Hugin to the k1, k2 etc. values in the XML... I'm guessing that a=k1, b=k2, etc... but something tells me that's too simple and logical to be correct

**jbinpg** · 07-12-2018, 03:49 PM - **1 Like**

Hi, Mike. If I remember my uni math courses right, k is a universal shorthand for a coefficient. So your assumption is likely correct. I read recently where one of the lens correction developers is throwing in the towel re. trying to stay on top of including new lenses in the hardcoded lookup tables. Instead they have allowed users to define their own lenses locally that will be scanned and loaded during instantiation. Can't remember if this was lensfun or exiv2 but I can certainly see their point given the plethora of lenses out there with similar and confusing definitions. I assume there will be a way to also pull in matching lens corrections. - Jack

aaacb · 07-12-2018, 04:42 PM - **1 Like**

Found this other page too after my first post, seems to be closer to what you wanted (guide on using hugin and lensfun), it mentions how to fill in values for different corrections.

Adding new lenses to the database

**bwgv001** · 12-18-2022, 10:40 PM

Would you be willing to share your lensfun entries with other forum members?

07-12-2018, 10:02 AM	#1
BigMackCam Digitiser of Film Join Date: Mar 2010 Location: North East of England Posts: 20,661	LensFun XML guide? I've just started producing lens calibration data for some of my lenses using Hugin's Calibrate Lens tool, and I'd now like to patch the relevant XML files locally to include the new lenses. Although I can sort of figure out what's required by looking at the existing XML, I'd like to be sure I'm doing it correctly. I understand that there used to be a manual written by Andrew Zabolotny at http://lensfun.sourceforge.net/manual/database.html, but it seems that's no longer available (I'm getting a 404 error). Does anyone have a copy of the manual, or alternatively, could someone explain to me exactly what's required? Any help would, as always, be very much appreciated. Thanks in advance Last edited by BigMackCam; 07-12-2018 at 10:36 AM.

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07-12-2018, 01:54 PM - 1 Like	#2
aaacb Pentaxian Join Date: May 2016 Photos: Gallery Posts: 3,724	Is this the XML doc you're looking for? It's linked from the API doc on the lens fun sourceforge page. Just guessing, haven't worked with lensfun before. lensfun: Database file format

07-12-2018, 03:13 PM - 1 Like	#3
BigMackCam Digitiser of Film Join Date: Mar 2010 Location: North East of England Posts: 20,661 Original Poster	Originally posted by aaacb Is this the XML doc you're looking for? It's linked from the API doc on the lens fun sourceforge page. Just guessing, haven't worked with lensfun before. lensfun: Database file format That's a big help - thank you! I can figure out most of what I need to do from that... the only thing (I think) that I'm missing is how to map and/or calculate a, b, c values in Hugin to the k1, k2 etc. values in the XML... I'm guessing that a=k1, b=k2, etc... but something tells me that's too simple and logical to be correct

07-12-2018, 03:49 PM - 1 Like	#4
jbinpg Site Supporter Join Date: Mar 2008 Location: Prince George, BC Photos: Gallery \| Albums Posts: 3,546	Hi, Mike. If I remember my uni math courses right, k is a universal shorthand for a coefficient. So your assumption is likely correct. I read recently where one of the lens correction developers is throwing in the towel re. trying to stay on top of including new lenses in the hardcoded lookup tables. Instead they have allowed users to define their own lenses locally that will be scanned and loaded during instantiation. Can't remember if this was lensfun or exiv2 but I can certainly see their point given the plethora of lenses out there with similar and confusing definitions. I assume there will be a way to also pull in matching lens corrections. - Jack

07-12-2018, 04:42 PM - 1 Like	#5
aaacb Pentaxian Join Date: May 2016 Photos: Gallery Posts: 3,724	Found this other page too after my first post, seems to be closer to what you wanted (guide on using hugin and lensfun), it mentions how to fill in values for different corrections. Adding new lenses to the database

12-18-2022, 10:40 PM	#6
bwgv001 Site Supporter Join Date: Aug 2015 Location: Alabama Photos: Gallery Posts: 697	Would you be willing to share your lensfun entries with other forum members?

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