Exif -- lens reporting incorrect data

GrahamB wrote: My Tamron 90mm f/2.8 macro is reported as a 100mm f/2.8...

PaintShopPro in all its versions has always reported it correctly. I suggest you change your PP program.

It also distinguished between the two Sigma macros I have owned.

I don't know about the other editing software, but Adobe do have downloadable profiles for a number of cameras / lenses. They also have a program for creating lens profiles with provision to supplement their own list. Just Google Adobe Lens Profile Creator. That list isn't very comprehensive - yet!

I have a large number of A mount lenses from various makers, some are quite old lenses for Minolta film cameras which are mostly missing from the Adobe list. So far, I haven't found any that are not correctly identified by ExifTool although I haven't checked all of them yet.

Bob Maddison wrote: I don't know about the other editing software, but Adobe do have downloadable profiles for a number of cameras / lenses. They also have a program for creating lens profiles with provision to supplement their own list. Just Google Adobe Lens Profile Creator. That list isn't very comprehensive - yet! I have a large number of A mount lenses from various makers, some are quite old lenses for Minolta film cameras which are mostly missing from the Adobe list. So far, I haven't found any that are not correctly identified by ExifTool although I haven't checked all of them yet.

The miss-identification of 3rd party lenses is only in the database function of Lightroom. Say I want to see all the images I've shot with the Tamron 90mm macro on the a77. The database identifies all the images as having been shot with the 100mm macro.

Once I select the file for development, it returns the correct focal length (also the correct focal length for the appropriate zoom setting on my Tamron 28-75mm f/2.8). Adobe also correctly chooses the appropriate lens correction profile and applies it, although I'm sure that's only because I set the default profile for that identified lens. I could choose to associate a Minolta 20mm profile for my Sigma 20mm (or a Nikon 300mm for the Sigma 20mm), and Lightroom would apply that profile automatically.

It's really a minor point, but as other software programs correctly identify 3rd party lenses, I don't know why Adobe can't. It's a niggle I'm always likely to have, as I have 4 M645 Mamiya lenses I use with a Mirex T/S adapter, along with a Contax 28mm CZ on an un-chipped Leitax mount. I try to record the lens used in my shoot notebook, but I'm not always able to do so at the time. Later is often a guessing game.

What I'd like to see, is a plug-in that makes editing the metadata, or Adobe database a simple task. Allow me to save it as a preset, to apply to multiple images on the LR library light table.

Graham

Edited by GrahamB - 04 July 2012 at 00:18

robertsmx wrote: Lens Type Value translation (EXIF Tool): 25     = Minolta AF 100-300mm F4.5-5.6 APO (D) or Sigma Lens 25.1     = Sigma 100-300mm F4 EX (APO (D) or D IF) 25.2     = Sigma 70mm F2.8 EX DG Macro 25.3     = Sigma 20mm F1.8 EX DG Aspherical RF 25.4     = Sigma 30mm F1.4 EX DC 25.5     = Sigma 24mm F1.8 EX DG ASP Macro

The .X is added to the list as a shorthand for exiftool, but the lenses themselves all report just 25 with no decimal.

Lens type tag has been around for decades. It's a makernotes tag rather than exif, so different tag address for other brand bodies, but basically the same approach, except Nikon which uses a different system with more detail.

Sony cameras except A100 write more metadata "tags" in addition to lens type. One additional tag, lensspec, in Sony makernotes starting 2007, two more in exif tags in 2010 after exif 2.3 was released. Sony lenses started supplying more info to camera in 2007 also. Older lenses don't supply this info, but some recent Sony bodies (starting A77?) have an internal lookup table for lens type to be able to write the new exif tags. Lookup only contains Sony and Minolta lenses.

Some photo editing programs look for the newer tags and some don't. Some editing programs transfer only exif to saved copies, so the makernotes tags in the original raw or jpg are dropped. Editing programs that look only for the original lens type tag will make more mistakes. Some edit programs allow you to set preference for resolving ambiguous lens type and/or to override automatic selection.

If your editor will read them, You can add the new exif tags to images that don't have them with exiftool or other metadata editors.

The Dyxum digital darkroom forum has more detail, as do the

exiftool forums

edited to add links and correct typos


Edited by analytical - 04 July 2012 at 00:10

Readers here might be interested to cross reference a related thread that I placed in the Lens Talk forum (which is probably where this should more properly be?) referring to EXIF errors coming up in post production software when using third party lenses.
It covers much the same ground but there are quite a few additional very technical and detailed contributions from members sitting there.
Maybe the Mods/Admins should consolidate this data into one thread under Lens Talk?
Here's the link http://www.dyxum.com/DFORUM/exif-errors-with-sigma-lenses_topic85008.html?KW=
Joe

The three threads are now merged.

Took about a hour and drove me cross-eyed.

I think we need to jazz up the heading!

@ Joe -- new title and see the OP here.