https://blog.gongquiz.com/2022/08/05/%ec%a7%80%eb%a6%84-50mm%ec%9d%b8-%ec%b6%95%ec%97%90-%eb%b3%b4%ec%8a%a4%ec%9d%98-%ea%b8%b8%ec%9d%b4-50mm%ec%9d%b8-%ea%b8%b0%ec%96%b4%eb%a5%bc-%eb%b6%99%ec%9d%b4%eb%a0%a4%ea%b3%a0-%ed%95%a0-%eb%95%8c-25/