"It is wide angle lens" doesn't work.
I'm not convinced they are correct (note deliberate use of the ungrammatical but popular singular 'they'), because hyper-correctism seems to be increasing as well. The population seems to be splitting into those who can't use correct grammar, and sticklers, with a reduced middle ground of the relaxed.
It'll be OK.
So you don't say "it's" for the same reason you don't say "hi's".
Rules can change over time and you do not need a governing body for rules to exist as rules are just as easily defined by consensus as by imposition.
It is generally known that its and it's have different meanings. People may regularly confuse them and the confusion may eventually eliminate the rule, but that does not mean there is currently no rule.
Or to put it another way, if English has no rules, have understand problem no will sentence you this to.
I usually refer to this handy illustrated guide http://theoatmeal.com/comics/apostrophe :D
Sadly, no. "It's been like this for days."