Knowledge, Education and Experience
Creating a good portrait is more difficult because your photographer is hired to use the specialized knowledge of posing, lighting, and technical skill; a knowledgeable photographer applies this talent in multiple environments.
Your photographer provides many service hours in travel, communication, archiving and backing up and post-session processing of your images.
Your photographer also ensures delivery of a quality materials from a professional lab so that your finished so that your purchase will be a legacy preserved for years without degrading.
Your are hiring a professional, not a hobbyist. So your photographer is growing a business that includes all the business and the means of providing for himself and his family.