Numbers - Re: "F Number" vs. "Aperture Value"
Johannes Zarl-Zierl <[email protected]> Mon, 02 Dec 2019 23:47:35 +0100
| Newsgroups | gmane.comp.kde.kimdaba |
|---|---|
| Message-ID | <2121795.GZGaBX18tE@mani> |
As an addendum, here is a rough translation table based on my exif database. Taking a closer look at the invalid values reveals that not all cameras store the APEX value at all: sqlite> select count(*) from exif; 30492 sqlite> select count(*) from exif where Exif_Photo_ApertureValue < 0.1; 24395 sqlite> select count(*) from exif where Exif_Photo_FNumber < 0.1; 4135 sqlite> select Exif_Photo_ApertureValue, Exif_Photo_FNumber from exif group by Exif_Photo_ApertureValue order by Exif_Photo_ApertureValue; -2147483648.0|0.0 -1.0|-1.0 0.970854|1.4 1.0|1.4 1.356144|1.6 1.53|1.7 1.531069|1.7 1.695994|1.8 1.85|1.9 1.851998|1.8999 2.0|2.0 2.2|-1.0 2.27|2.2 2.275007|2.2 2.27500704754745|2.2 2.27500712453691|2.2 2.27500720668781|2.2 2.28|2.2 2.375|2.2 2.52|2.4 2.52606882168926|2.4 2.625|2.5 2.643856|2.5 2.64385628700256|2.5 2.663|2.663 2.75|2.6 2.76|2.6 2.8|-1.0 2.81|2.65 2.86|2.7 2.96875|2.8 2.97|2.8 2.97085357390701|2.8 2.97085380554199|2.79999995231628 2.970854|2.8 3.0|2.8 3.3|3.2 3.34375|3.2 3.35614371299744|3.20000004768372 3.356144|3.2 3.375|3.2 3.4|3.3 3.5|3.4 3.53125|3.4 3.6|3.6 3.6147096157074|3.5 3.61471|3.5 3.61471557617187|3.5 3.625|3.5 3.7|3.6 3.8|3.7 3.9|3.8 4.0|4.0 4.1|4.2 4.3|4.5 4.33984375|4.5 4.339844|4.5 4.33984994888306|4.5 4.33985|4.5 4.34375|4.5 4.375|4.5 4.4|4.6 4.5|4.8 4.52|4.8 4.53125|4.8 4.6|5.0 4.625|5.0 4.643856|5.0 4.64385604858398|5.0 4.64385986328125|5.0 4.65625|5.0 4.9|5.5 4.90625|5.5 4.96875|5.6 4.97085380554199|5.59999990463257 4.970854|5.6 4.97085571289062|5.6 5.0|5.6 5.3|6.2 5.31069946289062|6.3 5.310704|6.3 5.3125|6.3 5.375|6.3 5.4|6.4 5.5|6.8 5.6|7.1 5.625|7.1 5.655638|7.1 5.6556396484375|7.1 5.7|7.1 5.8|7.4 5.9|8.0 6.0|8.0 6.2|8.6 6.33984375|9.0 6.33985|9.0 6.375|9.0 6.4|9.1 6.5|9.6 6.625|10.0 6.64385986328125|10.0 6.91886901855469|11.0 7.0|11.0 7.375|13.0 7.40087890625|13.0 7.400879|13.0 7.61471557617187|14.0 7.625|14.0 8.0|16.0 8.33984375|18.0 8.375|18.0 8.625|20.0 8.64385986328125|20.0 8.918863|22.0 9.0|22.0 Am Montag, 2. Dezember 2019, 23:32:30 CET schrieb Johannes Zarl-Zierl: > Hi, > > Forgive me my technical illiteracy - I didn't realize that there are two > almost identical measures at play here. > > The value called "Aperture Value" in the UI corresponds to > Exif.Photo.ApertureValue, which is the APEX[1] value. > The value called "F Number" is Exif.Photo.FNumber, which is the focal ratio > as commonly used. > > For better clarity, I propose we relabel the first entry to "Aperture Value > (APEX)" and the second one to "Aperture Value (F Number)". > > >From what I've read about APEX though, I conclude that the APEX aperture > >value > should have different values, i.e. the range is probably incorrect. > > Cheers, > Johannes > > > > [1] https://de.wikipedia.org/wiki/Additive_System_of_Photographic_Exposure > > Am Sonntag, 1. Dezember 2019, 02:49:26 CET schrieb Johannes Zarl-Zierl: > > Hi Robert, > > > > Am Samstag, 30. November 2019, 03:41:28 CET schrieb Robert Krawitz: > > > Why are there two separate controls in the search dialog? They mean > > > the same thing (but don't have the same effect -- one finds zero > > > matches while the other finds the correct matches). > > > > That's an interesting question. A casual glance at the source code doesn't > > help, unfortunately: apparently both the aperture and the f-number were > > added within a short amount of time (33cfb31cf vs 803e77395). > > > > My best guess is that fnumber was first renamed to aperture, and then a > > mistake was made when applying some patch, reintroducing fnumber... > > > > Johannes > > > > _______________________________________________ > > KPhotoAlbum mailing list > > [email protected] > > https://mail.kdab.com/mailman/listinfo/kphotoalbum > > _______________________________________________ > KPhotoAlbum mailing list > [email protected] > https://mail.kdab.com/mailman/listinfo/kphotoalbum