I have a Nikon D800 with a 24-70 mm lens and a 70-200 lens. These are standard lenses for the camera. The filter GimpLensfun shows the camera (as well as the D800e) but doesn't have entries for either of my lenses. I've been trying to use the filter leaving the lens choice blank. Does that make any sense? Something happens, but I' m not sure the correction is accurate.

I usually shoot NEF and use darktable to process my images, and that has the same problem. It show the same choices of lenses but neither of the standard lenses. Presumably the problem is with the Lensfun database. I know that I can in principle produce correction tables myself, but it seems like a lot of work, and I haven't been able to figure out how to do it.

Leonard Evens len@math.northwestern.edu
Professor Emeritus, Department of Mathematics, Northwestern University

On Fri, 2013-09-27 at 22:17 -0500, Leonard Evens wrote:

I have a Nikon D800 with a 24-70 mm lens and a 70-200 lens. These are standard lenses for the camera. The filter GimpLensfun shows the camera (as well as the D800e) but doesn't have entries for either of my lenses. I've been trying to use the filter leaving the lens choice blank. Does that make any sense? Something happens, but I' m not sure the correction is accurate.

I usually shoot NEF and use darktable to process my images, and that has the same problem. It show the same choices of lenses but neither of the standard lenses. Presumably the problem is with the Lensfun database. I know that I can in principle produce correction tables myself, but it seems like a lot of work, and I haven't been able to figure out how to do it.

Let me add that I checked /usr/share/lensfun and while it doesn't have an entry for the 24-70 mm lens, it does have one for the 70-200 lens. So why doesn't GimpLensfun show that lens as a choice for the d800? Where is it getting its information about lenses if not from that file?

Leonard Evens len@math.northwestern.edu
Professor Emeritus, Department of Mathematics, Northwestern University

On Sat, 2013-09-28 at 07:58 -0400, Partha Bagchi wrote:

Lensfun has tutorials to add your own lens if it does not show up. Have you tried those yet?

Yes. There are several ways to do it, including using hugin, which I have some experience with.

On Sat, Sep 28, 2013 at 12:59 AM, Leonard Evens wrote:
On Fri, 2013-09-27 at 22:17 -0500, Leonard Evens wrote: > I have a Nikon D800 with a 24-70 mm lens and a 70-200 lens. These are
> standard lenses for the camera. The filter GimpLensfun shows the
> camera (as well as the D800e) but doesn't have entries for either of my
> lenses. I've been trying to use the filter leaving the lens choice
> blank. Does that make any sense? Something happens, but I' m not sure
> the correction is accurate. >
> I usually shoot NEF and use darktable to process my images, and that has
> the same problem. It show the same choices of lenses but neither of the
> standard lenses. Presumably the problem is with the Lensfun database.
> I know that I can in principle produce correction tables myself, but it
> seems like a lot of work, and I haven't been able to figure out how to
> do it.
>

Let me add that I checked /usr/share/lensfun and while it doesn't have
an entry for the 24-70 mm lens, it does have one for the 70-200 lens.
So why doesn't GimpLensfun show that lens as a choice for the d800?
Where is it getting its information about lenses if not from that file?


--
Leonard Evens len@math.northwestern.edu Professor Emeritus, Department of Mathematics, Northwestern University

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Leonard Evens len@math.northwestern.edu
Professor Emeritus, Department of Mathematics, Northwestern University

On Sat, 2013-09-28 at 17:57 -0400, Partha Bagchi wrote:

Here is something you can try. Copy the lens database from svn: http://svn.berlios.de/wsvn/lensfun/trunk/data/db/ and put it the appropriate location within lensfun-0.2.7. Rebuild lensfun and you should have the D800 with 24-70.

Thank you. I may try that. But I don't really understand why it should be that hard. Presumably, the program darktable and the gimp filter gimplensfun are looking somewhere to find correction information. If it is not in /usr/share/lensfun, where in the world is it?

Personally, I think you should fix lens distortion (if any) within your raw editor rather than in Gimp, but that's me. :)

I ordinarily work in darktable on NEF fiiles, but I somehow managed to nuke a whole bunch of NEF images and had to instead work with the jpeg images on my backup card.

BTW, curious where did you read that the 24-70 is the "standard" lens for the D800? I have never heard of the D800 being sold with the 24-70 as a kit lens (or any lens for that matter).

It is perhaps an exaggeration to call these "the" standard lenses for the d800. When I was contemplating laying out a fortune for my D800, I posted a query at Nikonians about which lenses I should consider given my needs. The 24-70 and 70-200 lenses were both strongly recommended by several people. Also, my Calumet salesman recommended those same lenses. I think these lenses are common choices for use with the D800. They should definitely be in the Lensfun database, and if my reference above makes any sense, they are, so I am perplexed about why I can't find them.

Fortunately, my lenses have very little distortions, so I may be able to avoid using corrections.

The 14-24 lens was also recommended, but I didn't think I needed it, and I had already spent enough money. Later I got a 24 mm tilt-shift Rokinon lens which was something of a bargain for under $1,000.

Perhaps I should explain that I have been doing view camera 4 x 5 photography with 75 mm, 90 mm, 150 mm and 300 mm lenses. I wanted the Nikon D800 to cover roughly that range. 24 mm is relatively short for 35 mm but not as short as 75 mm is for 4 x 5, so someday I may get a shorter lens for my D800. One of my interests is architectural photography, and my 75 mm lens wasn't even short enough to photograph a building facade from across the street. I had to stitch two images using hugin to capture that scene. I think I can do the same thing easily, if the need arises, using 24 mm on my D800,

If I feel a pressing need, I may get a shorter focal length lens for the D800, but given that I am 80 years old, that need may never arise.

On Sat, Sep 28, 2013 at 12:29 PM, Alexandre Prokoudine wrote:
The only update that article needs is that apparently Hugin is now
capable of outputting XML data for LensFun.
Alexandre

On Sat, Sep 28, 2013 at 6:53 PM, Pat David wrote:
> Alexandre had a neat write up on lgw about using Hugin to generate
> correction parameters:
>
>
http://libregraphicsworld.org/blog/entry/creating-lens-distorsion-models-with-hugin-lens-calibrator >
>
> --
> pat david
> http://blog.patdavid.net
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Leonard Evens len@math.northwestern.edu
Professor Emeritus, Department of Mathematics, Northwestern University