Re: [Lensfun-users] Latest Database Files For Windows Users

[Torsten Bronger]

Hallöchen!

John J Bloomfield writes:

> [...]
>
> I did it a couple of months ago using the folder located at
> http://wilson.bronger.org/lensfun-db/version_1.tar.bz2 as
> mentioned in one of the project mailing list archives
>
> But I am now wondering is that folder/file being updated or was it
> just an idea that isn't being maintained?

It is maintained.  Unless my computer has serious trouble, at least.

> If it is being maintained perhaps it would be a good idea to make
> the link more obviously available?

It is meant to be used by a program only -- lensfun-update-data --
and therefore, I don't plan to advertise it specially.  Sometimes I
have to point people to
http://wilson.bronger.org/lensfun-db/version_0.tar.bz2 because that
is for Lensfun users with versions too old to be shipped with
lensfun-update-data.

Regards,
Torsten Bronger.

-- 
Torsten Bronger


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Re: [Lensfun-users] Latest Database Files For Windows Users

[John J Bloomfield]

Thanks for the feedback.

The submission I made us actually of an entirely different building that's
walking distance from my home that I suddenly thought about yesterday.

Sent from mobile I have big thumbs so sorry for for typos... I hope
they were amusing and not offensive. 

On 2 Jan 2018 7:39 a.m.,  wrote:

>
>
> On Sun, Dec 31, 2017, at 16:14, John J Bloomfield wrote:
> >
> > I'll shoot them all on FF (as I basic geometry makes me believe a FF
> > calibration should be able to be applied to APSC - but the opposite isn't
> > true) even though some are technically APSC lenses many do cover the
> whole
> > frame so are being commonly used.
>
> Yes, that's how it works.
>
>
> > Might not be the 100% accurate name as displayed in exif but I have;
> >
> >
> >- Pentax FA 77mm Ltd f1.8
> >- Pentax DFA 100mm f2.8 WR
> >- Pentax DA 50mm f1.8
> >- Pentax DA 35mm f2.4
> >- Pentax FA 28-70mm f4
> >- Pentax DAL 18-50mm RE WR
> >- Pentax DAL 50-200mm WR
> >- Sigma 17-50 f2.8
>
> I think there may be a Pentax lens or two in the backlog for calibration,
> unfortunately when I went to take a look today the server holding the files
> (including your recent upload) wasn't responding; I contacted Torsten
> Bronger, the owner, and hopefully it will be up and running soon.
>
> > I have spotted a couple of other buildings that should do for the job
> too.
> >
> > 1. - Is this Asda Store
> > 2. - University building
>
> The second one, assuming you can reasonably loiter there without
> attracting negative attention, looks ideal... a grid like that is always
> nice, even if not strictly needed.
>
> Otherwise, the important thing is at least one good, reliably straight
> line of sufficient length to allow you to stay at a reasonable distance
> even at wide angles. This line should be placed as close as possible to the
> edge of the frame, and fully span it. Many uploaded pictures don't get the
> line as close to the edge as they should, possibly due to differences
> between the viewfinder and what the RAW actually captures, so this is one
> issue to keep in mind.
>
> The importance of having a second line at 1/3 of the frame depends on the
> complexity of the distortion; if it displays any divergence towards
> "mustache" from simple barrel distortion, then this line is used for
> additional correction. Since this can make finding and using a suitable
> target more difficult, I've been thinking about the possibility of using
> two images with the camera simply tilted to position the line differently
> in each. I think this could be made to work, if need be. Also note that
> it's ok to change distance for different focal lengths on a zoom to get the
> best lines; the shots don't need to be taken from the same position.
>
> An additional consideration with crop lenses on full-frame bodies is to
> ensure that the frame-edge line is visible at both ends despite any corner
> shading the lens may produce. For TCA correction images, it would be good
> if the corners are fairly sharp and retain as much contrast as possible,
> even at the expense of the center of the frame being slightly less sharp
> and/or overexposed.
>
> Hopefully that clarifies some of the criteria for good calibration shots.
> It's also convenient if the uploader has a github account and can
> communicate directly within the numbered "issues" that each upload
> generates there, in the event that communication is needed.
>
> Oh, and for zooms, the ideal focal lengths (besides both ends of the
> range) are the point where distortion changes from barrel to pincushion
> (where applicable), and a few on either side of this, weighted towards the
> wider end. Often, once the distortion changes to pincushion, it doesn't
> change drastically over the rest of the range.
>
> I hope to have some time for working on profiles this week, knock on wood!
>
> --
> jys
>
> 
> --
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
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> Lensfun-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/lensfun-users
>
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Re: [Lensfun-users] Latest Database Files For Windows Users

[junkyardsparkle]

On Sun, Dec 31, 2017, at 16:14, John J Bloomfield wrote:
> 
> I'll shoot them all on FF (as I basic geometry makes me believe a FF
> calibration should be able to be applied to APSC - but the opposite isn't
> true) even though some are technically APSC lenses many do cover the whole
> frame so are being commonly used.

Yes, that's how it works.


> Might not be the 100% accurate name as displayed in exif but I have;
> 
> 
>- Pentax FA 77mm Ltd f1.8
>- Pentax DFA 100mm f2.8 WR
>- Pentax DA 50mm f1.8
>- Pentax DA 35mm f2.4
>- Pentax FA 28-70mm f4
>- Pentax DAL 18-50mm RE WR
>- Pentax DAL 50-200mm WR
>- Sigma 17-50 f2.8

I think there may be a Pentax lens or two in the backlog for calibration, 
unfortunately when I went to take a look today the server holding the files 
(including your recent upload) wasn't responding; I contacted Torsten Bronger, 
the owner, and hopefully it will be up and running soon.

> I have spotted a couple of other buildings that should do for the job too.
> 
> 1. - Is this Asda Store
> 2. - University building

The second one, assuming you can reasonably loiter there without attracting 
negative attention, looks ideal... a grid like that is always nice, even if not 
strictly needed.

Otherwise, the important thing is at least one good, reliably straight line of 
sufficient length to allow you to stay at a reasonable distance even at wide 
angles. This line should be placed as close as possible to the edge of the 
frame, and fully span it. Many uploaded pictures don't get the line as close to 
the edge as they should, possibly due to differences between the viewfinder and 
what the RAW actually captures, so this is one issue to keep in mind.

The importance of having a second line at 1/3 of the frame depends on the 
complexity of the distortion; if it displays any divergence towards "mustache" 
from simple barrel distortion, then this line is used for additional 
correction. Since this can make finding and using a suitable target more 
difficult, I've been thinking about the possibility of using two images with 
the camera simply tilted to position the line differently in each. I think this 
could be made to work, if need be. Also note that it's ok to change distance 
for different focal lengths on a zoom to get the best lines; the shots don't 
need to be taken from the same position.

An additional consideration with crop lenses on full-frame bodies is to ensure 
that the frame-edge line is visible at both ends despite any corner shading the 
lens may produce. For TCA correction images, it would be good if the corners 
are fairly sharp and retain as much contrast as possible, even at the expense 
of the center of the frame being slightly less sharp and/or overexposed.

Hopefully that clarifies some of the criteria for good calibration shots. It's 
also convenient if the uploader has a github account and can communicate 
directly within the numbered "issues" that each upload generates there, in the 
event that communication is needed.

Oh, and for zooms, the ideal focal lengths (besides both ends of the range) are 
the point where distortion changes from barrel to pincushion (where 
applicable), and a few on either side of this, weighted towards the wider end. 
Often, once the distortion changes to pincushion, it doesn't change drastically 
over the rest of the range.

I hope to have some time for working on profiles this week, knock on wood!

-- 
jys

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Re: [Lensfun-users] Latest Database Files For Windows Users

[John J Bloomfield]

Hi Jys,

Thanks for the response - are you part of the dev team?

I can see that the files are available but I am a working photographer
rather than a techie so I hesitate to use those files.

I use ACDsee and Affinity photo both of which rely on lensfun so I've only
recently become aware of the database when a lens profile I needed wasn't
available - but it was listed on lesnfun - it was actually really simple
using that tarball to update the software. I have now though just upgraded
to a Pentax K-1 and there are very few lens profiles available. I have a
load of lenses so I was going to just drive down to a local retail park and
shoot a set of calibration images for each - then hopefully they'll filter
through to the tarball and I can update my software but from the thread
where the tarball was first mentioned it is unclear if it was just an idea
or if it is being maintained (and indeed how to tell when it is updated)

I would really like to help strengthen the database with profiles for
Pentax as it seems all the real competition for Adobe products rely on it
and I don't really want to switch to Adobe - I like the stuff I use. (I do
hope that they've donated to the project as they so clearly rely on it)

Regards

John

www.deemo.co.uk
www.adviser-websites.co.uk

*When replying to us it would be great if you could 'reply all' that
strange long email address you see in the cc field copies your email in to
our customer jobs system so you will get faster service and your job notes
can be seen by anyone working on it. (The email address is different for
each job so don't bother saving it in your address book)*

On 29 December 2017 at 23:31,  wrote:

> The files in that tarball seem to have been last updated almost two months
> ago; I don't know what determines the schedule for that. The bleeding edge
> database is available at the git repository:
>
>  https://github.com/lensfun/lensfun/tree/master/data/db
>
> but there are a couple of caveats. The files are in "version 2" format,
> which needs to be backported for versions of lensfun < 0.3 due to
> restructuring. You would need to determine what version of lensfun your
> software is using. The repository is also subject to possible errors and
> subsequent corrections, so any use of it should probably include watching
> the repository for commits.
>
> --
> jys
>
>
> On Thu, Dec 28, 2017, at 06:22, John J Bloomfield wrote:
> > Hi
> >
> > I use several windows programs that use the lensfun database and it is a
> > simple job to manually update them.
> >
> > I did it a couple of months ago using the folder located at
> > http://wilson.bronger.org/lensfun-db/version_1.tar.bz2 as mentioned in
> one
> > of the project mailing list archives
> >
> > But I am now wondering is that folder/file being updated or was it just
> an
> > idea that isn't being maintained? If it is being maintained perhaps it
> > would be a good idea to make the link more obviously available? If it is
> > not being maintained then how does one obtain the most up to date
> database
> > files for the purposes of updateing a windows program?
> >
> > Many Thanks for all your hard work.
> >
> > John
> > 
> --
> > Check out the vibrant tech community on one of the world's most
> > engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> > ___
> > Lensfun-users mailing list
> > Lensfun-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/lensfun-users
>
> 
> --
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> ___
> Lensfun-users mailing list
> Lensfun-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/lensfun-users
>
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Re: [Lensfun-users] Latest Database Files For Windows Users

[junkyardsparkle]

The files in that tarball seem to have been last updated almost two months ago; 
I don't know what determines the schedule for that. The bleeding edge database 
is available at the git repository:

 https://github.com/lensfun/lensfun/tree/master/data/db

but there are a couple of caveats. The files are in "version 2" format, which 
needs to be backported for versions of lensfun < 0.3 due to restructuring. You 
would need to determine what version of lensfun your software is using. The 
repository is also subject to possible errors and subsequent corrections, so 
any use of it should probably include watching the repository for commits.

-- 
jys


On Thu, Dec 28, 2017, at 06:22, John J Bloomfield wrote:
> Hi
> 
> I use several windows programs that use the lensfun database and it is a
> simple job to manually update them.
> 
> I did it a couple of months ago using the folder located at
> http://wilson.bronger.org/lensfun-db/version_1.tar.bz2 as mentioned in one
> of the project mailing list archives
> 
> But I am now wondering is that folder/file being updated or was it just an
> idea that isn't being maintained? If it is being maintained perhaps it
> would be a good idea to make the link more obviously available? If it is
> not being maintained then how does one obtain the most up to date database
> files for the purposes of updateing a windows program?
> 
> Many Thanks for all your hard work.
> 
> John
> --
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> ___
> Lensfun-users mailing list
> Lensfun-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/lensfun-users

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