Interesting... He calls it exifixer, but the download is exifer1_5.zip. Confusing.
I did basically what you are talking about, Thinkdreams, only using exif(ix)er. Was scoping out the size of trying to do it using PJMT so I could also get access to XMP data. Frankly, the PJMT toolkit seems exhaustive--it will act on a variety of different files and decode a huge amount of metadata, whether EXIF or XMP or whatever else. After reviewing what metadata is attached to a simple jpg, I can actually understand why Adobe Photoshop's "save for web" function strips it all out... The data payload has to be pretty big and 99.9% of any web apps aren't going to make use of it.
That said, it would have been nice of them to leave stuff like the copyright in place...
I took another look at PJMT, and hacking that one is going to be rough. Exif(ix)er certainly has the benefit of compactness and an awful lot of bang for the buck. Its nicely commented, too. And, it seems compatible with a lot of cameras; while I shoot a variety of Nikons, I had it decode some stuff shot with point-and-shoots, and it did a good job.
Perhaps I'm feeling lazy right now, but I'm thinking the marginal benefit of a robust PJMT implementation is probably not worth it just to get lens data. Frankly, I'm wondering if there is some persistent EXIF field I can simply copy the data into--I typically fill in the "Artist" and "Copyright" fields, so one more is no big deal (esp. since its a cut-n-paste from another metadata field I can get to in Adobe Bridge, and since I probably shoot with one lens 80% of the time).
Tristan, if you are going to pick up exif(ix)er, I'll look back at what I did. I think I ran into some oddities with the way he did certain things, like long exposures--"300/10s" and stuff like that. If I can figure out what I changed, I'll try to post the modifications. He also uses PHP short codes in a couple of includes that my host barfs on.