Exiv2

The "Canon EF-S 55-250mm f/4-5.6 IS II" is lens #54:

[axa@enyo tmp]$ exiv2 -pa IMG_1758.jpg | grep Lens
Exif.CanonCs.LensType Short 1 (54)
Exif.CanonCs.Lens Short 3 55.0 - 250.0 mm
Exif.Canon.LensModel Ascii 70 EF-S55-250mm f/4-5.6 IS II
[axa@enyo tmp]$ ~/src/exiv2/bin/exiv2 -pa IMG_1758.jpg | grep Lens
Exif.CanonCs.LensType Short 1 Canon EF-S 55-250mm f/4-5.6 IS II
Exif.CanonCs.Lens Short 3 55.0 - 250.0 mm
Exif.Canon.LensModel Ascii 26 EF-S55-250mm f/4-5.6 IS II
[axa@enyo tmp]$ cd ~/src/exiv2/
[axa@enyo exiv2]$ svn diff
Index: src/canonmn.cpp ===================================================================
--- src/canonmn.cpp (revision 3035)
+++ src/canonmn.cpp (working copy)
@ -510,6 +510,7 @ { 51, "Canon EF-S 18-135mm f/3.5-5.6 IS" }, { 52, "Canon EF-S 18-55mm f/3.5-5.6 IS II" }, { 53, "Canon EF-S 18-55mm f/3.5-5.6 III" },
+ { 54, "Canon EF-S 55-250mm f/4-5.6 IS II" }, { 94, "Canon TS-E 17mm f/4L" }, { 95, "Canon TS-E 24.0mm f/3.5 L II" }, { 124, "Canon MP-E 65mm f/2.8 1-5x Macro Photo" },