Quote - I have a lovely trap I've been wanting to set for a while. Maybe now is the time to do it.

I believe I can prove (prove!) that one of the two following statements is true to you (not at the same time, but one of them is true)

• There is no such thing as copyrightable material of any kind.

• There is such a thing as copyrightable material, but every image ever made is a copyright violation of ever other image ever made.

Nice try but no cigar.
Copyright is to protect original expression in tangible form, there can't be a violation even if two expressions are exactly the same provided they were created independantly.

====

Onto the lens number case :-
Whether or not the number is copyright (seems very unlikely), if the number for any particular lens is available from his website, then I'd imagine that pretty much everybody would link to the information rather than quoting the number directly purely out of respect for the effort taken to obtain it and a desire that he'll continue to collect and provide future information.

If the method of obtaining the number was patented (i.e. you'd need a license to get the number from first principles yourself) the number generated wouldn't have any special protection.

Even if the method was truely a trade secret, the number would only also be a trade secret if there was some agreement (explicit or implicit) that you would treat it as such.
Copyright is the wrong branch of IP for this.

The place where copyright may be applicable (in some juristrictions) is for the whole collection.
An analogous situation would be that no single phone number is copyrightable, but phone books are.