How is someone judged on generosity?

For example, say a multi-billionaire decides to give away £500,000 to a charity, so basically a lot, but not a huge amount for him, compared to a poor man giving away moderate amounts of money, but was a significant amount for him. Am I right in thinking that whilst both being seen as good, the poor man would be seen as better because he's being more generous, although technically helping less that the rich man?