Currently, the "shopping" close reason says
Questions seeking product or service recommendations are off-topic because they tend to become obsolete quickly. Instead, describe your situation and the specific problem you're trying to solve.
This is true (especially for camera bodies!) there are other reasons, too. Could we modify this to something like?
Questions seeking product or service recommendations are off-topic because answers are highly dependent on individual preference and tend to become obsolete quickly. Instead, describe your situation and the specific problem you're trying to solve.
Or if we have space:
Questions seeking product or service recommendations are off-topic because answers are highly dependent on specific needs and individual preference. There are so many different camera lenses on the market because they all fit different needs and compromises. Also, camera recommendations tend to become obsolete quickly as new models replace older ones continuously. Instead, describe your situation and the specific problem you're trying to solve.
(Note that I've also changed the target for embedded link to a meta post from the "QA is hard!" blog post, because while that covers a lot of the issues, I think its tone could be interpreted badly by new users.