I'd have to know a little more about the men other than the photographer.
Does your wife know them or are they co-workers?
How well does the host know these men? Has he 'socialized' with any of them in the past?
If the host has taken photos of your wife before, it 'sounds' like he has set a session up for her to model for all of these men. I would assume he would have informed your wife of this at the time of invitation, and perhaps suggested a wardrobe...or none at all!
If it is indeed "safe" for your wife to attend, that could be quite thrilling and stimulating! We all generally want our wives to fuck, of course, but the thought of her ******** the most private parts of her body to that many men and letting them take dozens of photos is very erotic in itself.