Facebook open graph meta tags maximum content length

Does anyone know the maximum valid length for each of Facebook's open graph meta tags?

The description of the meta tags on http://ogp.me/ does not list maximum lengths, only general descriptions such as "A one to two sentence description of your object" for the og:description meta tag.

From what I understand, there is no maximum content length for meta tags in general, just recommendations to keep them under certain lengths for SEO reasons.

I'd be curious to know if there is a hard limit and what the limits are for what is visible on a link posted to Facebook.