Based on the level of respect or formality, you can say "My hobby is camping" in Korean in 3 ways:

• Informal: nae chwimi-neun kaemping-iya (내 취미는 캠핑이야)
• Formal: nae chwimi-neun kaemping-iyeyo (내 취미는 킴핑이예요)
• Very formal: je chwimi-neun kaemping-imnida (제 취미는 킴핑입니다)